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Thread: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the 645D

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    Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the 645D

    Pentax FA 645 Lenses

    For the last 12+ months, I have been working intensely with multiple samples of Pentaxís single focal length FA autofocus lenses designed primarily and initially for their 645 film system, by employing their use on their new Pentax 645D Digital MF body. A wide variety of lens samples was primarily obtained courtesy of long time associations with MF 645 and 67 Pentax photographers, who kindly lent samples of their lenses for this project as well as my own purchases of lenses.
    Iíve also had the opportunity to work with and test a small sample of their FA zooms.

    Much has been written about the new Pentax 645D and by accounts it is extremely competent performer, a superb value and has shown to consistently deliver professional quality MF files. It is also an excellent handling camera with a great feature set. If there are limiting factors in this first offering by Pentax in the Digital MF marketing place, it was initially thought their film era developed line of medium format lenses might not be up to the task. Even by Pentaxís own accounts, only certain samples of some of their 645 lenses would perform well enough for use on the 645D at a high level. Prior to investing time and money into the system, I set out to determine just how extensive these concerns were. Employing both methodical testing of multiple samples of each lens as well as paying careful attention to shooting techniques, I wondered if I would be able to come up with a set of suitable excellent performing lenses in a variety of focal lengths necessary for my own particular shooting needs and whether it would be a too much of a daunting task or not. Happily I can report itís not, although very careful consideration to certain factors is necessary to achieve this goal. I limited myself primarily to FA autofocus 645 lenses for this first round of testing and although the numbers of samples of each focal length certainly doesnít qualify for statistical significance, hopefully it does show that with certain lenses, careful selection, testing and setting of AF fine tune in the 645D body, can be very important. I suspect unlike most MF users, especially landscape photographers, I often have the need and desire to use lenses at more open apertures, therefore necessitating my testing of these lenses and to first determine the best AF fine tune adjustment for each individual sample before additional testing and consideration was performed.

    Determining the optimum AF fine tune setting did not always follow the convention of AF fine tune setting at minimum focusing distance and then allowing the increased depth of field as subject distance increased, to cover for any slight offset. Often times a subject distance at mid range or even infinity proved to be the best AF fine tune setting for a wide variety of applications. This was one of the most time consuming first steps when testing any lens and often a compromise subject distance was picked to determine the AF fine tuning setting, especially if the lens was to be used for a variety of camera to subject distances. If a lens was strictly going to be used for landscapes at infinity, then sharpness across the frame might be enhanced if AF fine tune setting was determined by testing at infinity. Spherical curvature observed in some lenses made this a necessity.

    Iíll also mention that all test files were examined at actual pixels (100%), so that many of the observations or issues presented in this report may not be evident if one is only concerned with looking at screen resolutions or slight magnification. Output to large format print was the primary goal, so observing at 100% became a necessity.

    Each lens was tested two ways:


    1. Camera/lens squared up to a frame filling brick wall and tested at minimum focus distance, mid-distance and the longest possible subject distance that allowed the frame to be filled with this test target. Lens was tested at all f-stops.

    2. Camera/lens was tested in real world shooting with a wide variety of subjects (at a variety of angles to the subject). Three camera to subject distances were employedÖminimum focus, mid-distance and infinity and at all f-stops. The one exception was the FA 120mm f4 macro, which was tested in a wider variety of subject to camera distances, due to its increased focusing range.

    The following observations are not a definitive statement of the optical potential of each focal length lens, as there are far too many samples of each lens produced over the years. What is apparent is often a moderately wide variability between samples when used at apertures wider than normally associated for landscape. One possible explanation of this performance variability is that these lenses were all produced (except for the new WR 55 f2.8) during the film era and although most might have passed quality control for optical performance on Pentax 645 film bodies, some samples fall short when confronted with the demands of a digital sensor. Lenses passing QC might have done so on either side (+/-) of a theoretical perfect ďnullĒ and therefore the further they are removed from perfect adjustment, the more issues they might present to the sensor. This imperfection is not only is restricted to front/back focus, which the 645D body can often compensate for (with AF fine tuning), but optical alignment of elements/grouping which determine lens performance when properly focused. This often encompasses skewing of elements, which may lead to asymmetry, which is often observed as a blurring of one or more sides or corners. Rough handling of used lenses was often thrown out as a possible cause of poor performance as most lenses I tested were originally purchased new lenses by the respective photographers and were handled with great care during the course of their use. The equivalent 35mm focal length of each lens when used with the 645D is noted in parenthesis ď( )Ē next to the actual focal length of each lens.

    Observations

    1. FA 35mm f3.5 (28mm) . This very popular lens is an excellent performer under most but not all shooting conditions. Itís performance varies greatly depending on subject distance, f-stop employed and whether the subject is greatly affected by the extensive spherical curvature this lens exhibits primarily at long camera to subject distances. I tested out more samples of this lens (greater than 10), than any other FA lens. The spherical curvature appears small at relatively short distances but quickly grows as the focusing distance increases. At typical landscape distances, many samples display enough spherical curvature so that edges/corners are softer than the central portion of the frame. If one though looks though at the edges/corners (such as the lower right and left ones) that are in the foreground of an infinity focused landscape, these corners are often sharp compared to the upper right and left corners at infinity. This is a result of this spherical curvature. Camera/lens angle and distance to the subject can also greatly influence this. Some barrel distortion is evident with this lens, but nothing thatís not easily correctable in post processing.

    ** One sometime strange observation Iíve observed with this lens is what Iíll refer to as a ďblur zoneĒ. Iíve noticed it in almost all samples (although not in all images with a well defined consistency) an area of the image where all detail in the subject is slightly blurred. Everything above/below and around that zone is sharp and itís certainly not due to movement of subject (unless a small area of an entire brick wall moved!). Iíve seen this at a wide variety of focus distances. Itís more prevalent at the wider apertures and decreases to an extent when stopped down. It comes and goes and I yet donít have a handle on a well defined set of parameters to ensure 100% of its appearance. Recently some other FA 35mm f3.5 lens shooters also independently noted this strange anomaly as well as one individual with their MF 35mm A 645 lens. If I had to describe it, it looks like a small group of tree leaves in an entire image of trees together with their leaves, had moved in the wind during exposure....while the rest of the entire mass of trees with their leaves contained in the rest of the image are perfectly sharp. Could it be due to the slightly uneven pouring of the resin used to make the aspherical containing lens element? Purely conjecture at this point and its rarely observed.

    Conclusion: A very fine lens, sharp but with somewhat better performance at close and mid-range. Still good for landscapes but depending on sample, edges/sides may be ďmore or less sharpĒ at infinity. Sweet spot on the 645D is between f11/f13. The lens really picks up in resolution at around f6.7, for those who desire to shoot at a wider apertures. CA is evident in brightly lit reflective situations, but itís fairly well controlled and doesnít present an issue when the lens is well stopped down. Sample to sample consistency is fair at best and there were notable differences. Getting the 645D AF fine tuning right with this lens is critical and makes a big difference in performance. AF fine tune settings varied greatly between different samples of this lens, with some of the widest variation in settings among FA lenses. Lens AF fine tune settings covered the range of +10 to -8. The AF fine tune setting also has a great effect on the presentation of spherical curvature with this lens and exactly how close or far back it presents itself in an image. A lengthy article would be required to describe the why and how the 645D AF fine tuning affects this, relative to keeping infinity sharpness respectable at a chosen setting. The MF 35mm f3.5 645 lens is mentioned by some to have slightly improved edge/corner performance than the FA version but with a notable increase of CA.

    2. FA 45mm f2.8 lens (35mm). Although a fast lens with a moderately respectful reputation with film users, I was previously made aware of itís less than stellar performance on the 645D. I only tested two samples and both performed similarly. The lens I suspect would not be favored by most critical users. Its central sharpness becomes respectable by f11/13 but the sides and corners are fairly soft.

    Conclusion: Itís not one of the group of lenses I would personally recommend when shooting with the 645D. . I didnít specifically test for CA and the AF fine tune setting between these two lenses appeared similar.

    3. FA WR 55 f2./8 (43mm) This newly released lens (at the same time as the 645D) has been much maligned, and in my opinion, often by word of mouth from those that havenít even shot with it or compared with lenses of similar focal length. Like the FA 35mm f3.5, Iíd recommend its use more for close and mid-distance or at landscape infinity distances, where ultimate edge/corner sharpness that matches central resolution isnít required. Contrast, possibly by design seems to be lower than the average FA lenses made in the film era. This too contributes to images that donít instantly pop out at the viewer. Lens can be used even wide open (with some edge/corner softness and small loss of central resolution) and of course is weather resistant like the 645D body, making an ideal pair, when the weather turns bad. Stopping down to its sweet spot of around f11 still presents edge/corner softness with some subjects in long distance shots. Whether this is important is up to how the lens is used or the particular subject matter. I tested 3 samples of this lens, and all were consistent with one another, including AF fine tune settings that only varied slightly and not far from a neutral ď0Ē setting.

    Conclusion: Overall itís a good-to very good lens as opposed to a maybe a great one but when considering itís WR (which does instill confidence when using it along with the 645D in the rain/snow), results in a ďplusĒ. It is also a quiet focusing lens for those situations where the whirling sound of a screw driven AF lens would be obtrusive. CA was evident but in very measure amounts and stopping down reduced what was evident. By stopping down the lens with each f-stop by starting at f2.8, presents an image that picks up resolution across the frame in a very even and predictable way.

    4. FA 75mm f2.8 (60mm) This is the ďLittle Engine That CouldĒ. Very small and light and feels cheaply made, this lens surprises all who try it on their 645D. Unlike most FA lenses which have a simple push-pull focus clutch mechanism to engage and disengage AF, this one has a little switch on the side which isnít as convenient. The lens was often the kit lens supplied with the Pentax 645 FA film bodies. At f2.8 image often are jittery and soft and in most cases not ideal. At f4 in some tested samples, things pick up and it can be used at this aperture in a pinch. Itís at f5.6 where this lens starts to shine. Lovely sharp images with good edge/corner performance at this f-stop and beyond with nice OOF rendition. Sweet spot at f11/13.

    Conclusion: Often found at remarkably good prices, this lens is what I would often suggest to a 645D users, especially at its price point and its convenient small size. One thing that does sometimes present an issue is its very high levels of CA under certain lighting situations. Some of the highest amounts of CA Iíve seen in a FA 645 lens and observed it in all 4 samples I tested. It can be dealt with in post processing to a good degree, or by stopping down to f8/11 where little evidence is seen. AF fine tune settings were all biased towards the ď-ď directions, just slightly off from ď0Ē. A gem of a lens for its price/performance although there is some performance variation from sample to sample.

    5. FA 120 f4 macro (96mm) If ever there was a lens to begin an adventure with for a 645D users, this is it! To start with, less variability in sample to sample performance in extensive testing, than any other lens in the FA line-up. Not only that, but itís the only FA lens where each one required no 645D AF fine tuning. This might be due to the precision and adjustment a macro lens requires prior to leaving the factory, even in the film days, since performance on both the close focusing range as well as infinity is desired. Lens is heavy and its weight surprises some. Itís well built and has a focus limiter switch which truly helps in focus hunting. Sharp images with good contrast are obtained edge to edge from macro range to infinity. A very consistent performer (I tested 4 samples) and although there may be a lens or two that might better it in one parameter or another, itís hard to beat its overall performance. Although f4 is good, it gets even better upon stopping down. It also able to get down to 1:1 macro. One glaring area where it falls short is its OOF bokeh in normal focusing range. Itís not terrible, but depending on background subject and lighting itís not the most attractive and for portrait work would not be my 1st choice in FA lenses.

    Conclusion: Most everyone agrees, this lens can always be counted on to be a superb consistent performer in almost all areas except possibly portrait work due to its somewhat unattractive bokeh at normal focusing distances. Even there one can make due. I am just beginning a project in using this lens in its macro range and so far performance is impressive. Shooting at f4 for general (non macro) subjects is very good but the lens like the WR 55 f2.8 lens gets progressively better when stopped down. Sweet spot seems to be around f11/13 although for general hand held use, f8 does well. CA is fairly well controlled at f4. A great lens with almost no reservations.

    6. FA 150mm f2.8 (120mm) The very first time I picked up one of these lenses, I though someone was playing a joke and removed some of the internal glass elements. After physically picking up the FA 120mm f4 macro, this lens seemed light, too light! A very pleasant surprise and knowing it was a f2.8 lens (as opposed to the 120mm f4 macroís f4), I was not prepared for this weight reduction. Unfortunately all was not good initially. The 1st sample was mediocre at best until f5.6 as was the 2nd sample. The 3rd sample was decent in the center from f2.8 but the edges/corners were terrible until f8. The 4th and 5th samples were better with the better of the two what I was hoping for. The best sample was reasonably sharp at f2.8 centrally, just about perfect for portrait work which its f2.8 aperture is ideal. At f4 it picks up some resolution, and was useful for most general hand held purposes. Edges and corners at f2.8 and f4 are respectable but do lag behind the center. At f5.6 the lens is in its element, good all around and this continues at f8/f11. Itís OOF attractive bokeh is far superior with this lens than the FA120mm f4 macro and along with its performance at the more open apertures, is an ideal portrait lens which one presumes it was intended for. Yet it does well as a nice relatively fast all around lens which due to speed, can be used hand held. Whether testing more samples will yield this wild variability, I cannot say, but it was worth testing these samples to find one that did not disappoint. My impression is its contrast is lower than the FA 120mm f4 macroÖwith a more gentle and delicate presentation. Again possibly due to itís roots as a portrait lens.

    Conclusion: Light for its focal length and speed, a lovely portrait lens and all around performer. It does benefit from stopping down somewhat. Good OOF bokeh and sharpness across most of the frame is achieved by f8 although may fall slightly short of the best of them. Itís a lens that a bit more delicate in itís image presentation and may not wow those looking for a higher contrast, slightly sharper lens. Each type of lens has its place and will greatly depend on subject and lighting. The main issue is finding a sample that performed as described. AF fine tuning required a +6 on the best sample with most others also on the + side of the scale. CA is evident with bright contrasty lighting but well within controllable amounts, especially after stopping down a stop or two.

    7. FA 200 f4 (160mm) Red flags were raised when I tested my first 4 samples. First three were simply horrible and fourth wasnít too much better and yet others that I asked, demonstrated fine performance with theirs (on their 645D). Images were jittery, blurred, and soft up to f7.1 Even the screen resolution shots didnít look particularly sharp as I figured this was just one of those lenses (the FA 200 f4) that doesnít interface well with the 645D. These samples were barely acceptable at f8 and decent by f11. If someone had one of these lenses in their possession and only shot at f11/13, they might or might not noticed decreased performance when pitted against a ďgoodĒ sample which I eventually came across. I even went back and tried one of these poor performing lenses on a 645 film body and the small prints looked good. I then used a scan and printed a little larger. Images were still fairly sharp and acceptable. After some time I was lucky enough to have the opportunity to test out two more samples. Both of these to my relief performed well by f5.6 and decently at f4. The lens was also of lower contrast, similar to that of the FA 150mm f2.8. At f8 the lens looked sharp but lacked bite compared with the best of them. The sweet spot was closer to f13 than f11. Edge corner performance by f9.5 was very good, but still fell short of the center. The FA 200 lens is relatively compact and is the longest focal length FA 645 telephoto thatís compact enough to take in a small bag. Next longer lens in line is the FA 300 f4, which makes a giant leap in size and weight as compared to the FA 200 f4.

    Conclusion: A good sharp lens, especially when stopped down, but the images it produces lacked excitement, for lack of a better description. Possibly ďneutralĒ is a better word to describe how it draws an imageÖcompetent but not exceptional with lower micro contrast than some other FA lenses. Itís relatively compact size and weight, make for a good travel telephoto, when more reach is required. CA is a better than average and so far hasnít been evident in any meaningful way.

    8. FA 300 f4 (240mm) A quite renowned lens thatís often mentioned as having excellent performance characteristics for a long MF telephoto. Size and weight is considerable if compared to most other FA telephotos. It has a built in rotatable tripod mount, but some flex and camera/lens vibration is quite evident and often spoils the shot. Optical performance is exceptionally good, even at f4 but improvement can be readily seen by stopping down a stop or more. Lens has excellent contrast and micro contrast and more than excellent sharpness by f5.6. Even with mirror lock-up, a stable tripod set-up and carefully selection of shutter speed, image robbing vibration was often evident. Various techniques were employed to reduce this with a degree of success. Although the lens is sharp, one should not expect the extreme sharpness and acuity of a Nikon 300mm f4 or 300 f2.8 SLR lens when itís shot wide open at f4. Itís just different yet never less impressive in its own way.

    Conclusion: If long range shooting is in ones plans, then this often expensive optic might just be the ticket to achieving ones goals. I didnít specifically test for CA and AF fine tuning on the three samples I tested two were slightly offset from ď0Ē and a third was +8/+9. This last sample though proved to be the best optically and most impressive. Other than size and weight and sometimes cost, this relatively fast telephoto can be a valuable assets if one desires a longer range telephoto that quite capable in the field. I have just begun testing the Pentax 1.4x converter with this lens and hopefully will report back my findings.

    9. FA 300 f5.6 (240mm) Based on the testing a single sample, this lens is lighter and more compact than its bigger brother, the FA 300 f4 with somewhat similar performance to the FA 300 f4 when stopped down. Contrast though is somewhat lower than the FA 300 f4 giving the impression of decreased sharpness when comparing the two. This lens comes into its own at just beyond f8. Sharpness is good, but I honestly canít say whether it matches the FA 300 f4, until further testing in comparing the two. Conclusion: More reasonably priced than the FA 300 f4 and lighter in weight, this lens may be a more sensible approach for those than donít use a long focal length lens in this range very often, especially when shooting MF. I didnít test for CA and AF fine tune setting was +1.

    10. FA 400 f5.6 (320mm). This lens by appearance looks like the big brother to the FA 300 f4. Larger, longer and heavier, this lens needs to have a specific purpose in order to find its way into many MF shooters bags. With all the attention given to the ďgold ringedĒ Pentax FA 300 f4 EDIF lens, I initially didnít have high expectations for the FA 400, especially that Pentaxís FA 400 f5.6 lens in 35mm format, was a disappointment from my extensive use of that lens. To much surprise, this lens optical performance was acceptably good at f5.6 but stopping down to f8 and beyond put this lensís performance close to the FA 300 f4. The look of this lensís images closely resembled the FA 300 f4 with somewhat lower micro contrast. It has fairly good resolution on axis and very good contrast at all apertures. Although it too has a built in rotatable tripod mount, it also suffers from the same image robbing properties due to vibration, much like the FA 300 f4 . Both these lenses benefit from some type of long lens support. Mirror slap in the 645D is well dampened and doesnít seem to be the primary contributor to these issues. Iím currently looking into what steps and techniques will help.

    Conclusion: A very fine relatively long telephoto although fairly big and heavy. Sharpness by f8 and especially by f9.5, should give those trying to extend the reach of their MF shooting, something good to work withÖ.especially if they keep in mind the requirement of employing exceptionally good long lens techniques. Both samples I tested also required slight offset from zero in selecting best AF fine tune settings. I didnít specifically test for CA. I plan some additional tests employing the 1.4x converter.

    11. FA 45-85 f4.5 zoom (36-68mm) . Although zoom lenses are often compromises when compared to their single focal length bretheran, this particular lens will certainly exceed the expectations of most. Sharp throughout most of its focal length range, itís good handling and design, although somewhat heavy, makes it a joy to work with. Its range is sufficient to cover general purpose shooting or for those times when only a single walk around lens is desired. At its wide end of 45mm sharpness is very evident, even wide open and improves upon stopping down. The same holds true for a zoom setting of 65mm. At both these focal lengths, sharpness extends well into the edges/corners and performance can be considered exceptional for a MF zoom. At 85mm things begin to change. Some spherical curvature sets in although in both samples, with optical alignment of elements (or group of elements) seemed to be slightly off, relegating one side/corner or the other to some blur within the focusing plane on one of the tested samples. Central sharpness is good, especially upon stopping down to f6.7 and beyond, but edge/corner sharpness lags behind, especially on the side where asymmetry is noticed. It doesnít quite ever catch up with center sharpness in the three samples I tested. The sweet spot for this lens, especially at 85mm would be f11/13, although I wouldnít hesitate opening up if necessary when shooting at 45-65mm. Some barrel distortion was evident, but relatively small and easy to deal with.

    Conclusion: Another very fine FA lens and one in which has grown on me, simply for itís acuity at 45-65mm and use of its focal length range. Itís not a complete substitute for single focal length lenses in its range, but can often compete for the job in many situations. All samples tested required significant AF fine tuning adjustment of +5 and +6 respectively. I havenít completed testing of these lenses nor have noticed any serious issues with CA while shooting.

    12. FA 80-160 f4.5 (64-128mm) . Iíve only worked with a single sample of this lens, so I hesitate to make any sort of pronouncement of its performance, especially related to other samplesÖ.although I have conferred with a few others who use this lens, when I noticed a slight bit of disappointing performance at its longer end. Whereas the FA 45-85 zoom at itís 85mm end shows its relative weakness, the FA 80-160mm seems to compensate for it (at 80mm) when these lenses are used as a sort of matching pair. It almost seems thatís what Pentax intended. Approaching 160mm, the lens sample I tested grew quite soft and only upon stopping down to f11/f13, did I feel it had sufficient resolution necessary for my own expectations.

    Conclusion: A handy focal length that may or may not be somewhat disappointing in optical performance. I simply need to test additional samples of this lens to make any definitive conclusion but have spoken to others who have used this lens on the 645D and although opinions varied, the majority felt it was simply good at its wider end but not the best of lenses. A few felt otherwise.

    13. A* 600 f5.6 (480mm). Recently Iíve started to put the Manual Focus (only) Pentax A* 600 f5.6 lens through its paces. It has no auto focus counterpart. A lens of modern design with a superb reputation among Pentax 645 users, Iím eager to see how it performs in a wide variety of situations, with and without the high quality Pentax 1.4x 645 teleconverter, which is often used with this lens. I hope to report on my findings at a later date.

    Just to note: I hope to eventually test out the new Pentax D FA 25mm f4 645 lens with the 645D sometime in the future (depending on availability). The few preliminary reports and images posted so far seem to indicate an exceptionally good lens, especially when stopped down. Center resolution appears somewhat ahead of corners. Unfortunately evidence of moderately high CA at the more open apertures appears to be clearly evident. Again this assessment was made by the few who were able to test out this lens on a 645D.

    Dave (D&A)
    Last edited by D&A; 16th March 2012 at 12:48.
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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Dave I am going to give this some time in this forum but with your permission I would love to move this in the review section for a more permanent home. This is awesome thanks for posting
    Photography is all about experimentation and without it you will never learn art.

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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by Guy Mancuso View Post
    Dave I am going to give this some time in this forum but with your permission I would love to move this in the review section for a more permanent home. This is awesome thanks for posting
    I was most definitely going to contact you first prior to posting to determine where you felt it would be most pertinant to post. Please, move it to whatever location you think would be best. Thanks!

    Dave (D&A)

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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Thanks Dave we will give it some time here than we can move it to the review section. Now for some reading. LOL
    Photography is all about experimentation and without it you will never learn art.

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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Dave, you have been threatening us with this for a long time. Excellent and thoughtful look at the Pentax optics. I also think the D FA 55mm has not quite had a fair shake and have found it to be a very good lens.

    I would be interested to see what you say about the 1.4X converter. I picked up the 300mm f/5.6 because of its weight and size and I am thinking about that converter.

    Thanks.

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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Thank you Shashin. The delay in posting was primarily due to the situation that unlike Leica S2 lenses for example, where there appears to be amazing consistancy between various sample of the same lenses (and rarely does there appear any need to determine how good a sample is).....this is unfortunately far from being the case with Pentax 645 lenses for obvious reasons, since not only were the vast majority designed and adjusted during the film era, but many are simply well used and old.

    I too think the new 55mm hadn't been given a fair shake but I think expectations were that each sample (since its newly designed in the digital era), would have particulary good edge to edge sharpness, even by f4.5-f5.6. It was also designed as the showcase lens for the 645D. Unfortunately that wasn't quite the case but on the other hand, the new Pentax 55mm lenses are consistant performers and even when used at wider apertures, the central part of the frame is exceptionally good. It all depends on ones own use and application. For myself personally, I too like the lens a lot and combined with it's WR, I find is an invaluable tool for outdoor work, especially if one finds themselves in less than ideal weather.

    Lastly regarding the 1.4x converter, I don't know what to expect....simply because medium format telephotos by themselves pose vibration/stability problems and the inclusion of the 1.4x in the optical path not only will possibly compound this problem, but the resulting increase in focal length is that much harder to work with on a 40MP cropped sensor. Again I might prove myself wrong, so we'll have to see.

    Knowing the sample of the FA 300 f5.6 I used, I'm not certain the 1.4x would be a good match unless you are well stopped down to f13 at a minimum and even then not confident (at this point). A quick and fast 20 min test quite some time ago with the FA 300 f4 lens, which the 1.4x was designed for (or actually was designed for it's manual focus counterpart), I found it took exacting technique and stopping down the lens as well, to achieve an image I was satisfied with but often it could be "hit or miss". The use of the 1.4x (testing) on the A*600mm f5.6, due to the mass of the lens, might help provide some additional success.


    *** Lastly I should mention that I inserted some corrections and added some additional info into the text of the orignal lengthy post above.

    Dave (D&A)

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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Nice to see this Dave. Where did you find a 600mm A*? I look forward to your report on that lens.
    I tested a couple 1.4x converters with my 400. Vibration from the shutter is already an issue with the 400 and 1.4x makes it a major problem; it works quite well if you can avoid slow shutter speeds or really stablize the camera.

    I think the old 55mm is a better lens than commonly believed as well. I've compared mine to my 67 55mm, which regarded as one of the best in the 67 line and the 645 lens is better on the 645D, at least with my copies of those lenses.

    Tom

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    Re: Comprehensive Testing, Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by tsjanik View Post
    Nice to see this Dave. Where did you find a 600mm A*? I look forward to your report on that lens.
    I tested a couple 1.4x converters with my 400. Vibration from the shutter is already an issue with the 400 and 1.4x makes it a major problem; it works quite well if you can avoid slow shutter speeds or really stablize the camera.

    I think the old 55mm is a better lens than commonly believed as well. I've compared mine to my 67 55mm, which regarded as one of the best in the 67 line and the 645 lens is better on the 645D, at least with my copies of those lenses.

    Tom
    Thanks very much Tom. This particular A* 600 f5.6 is from an aquantence who lived overseas but just recently moved back here to the States. It may eventually be available, but its too soon to know (and whether I even have a need for such a lens at the present may be questionable). I'm in the preliminary process of testing it with and without the 1.4x. A few have been known to set up somewhat elaborate rigs to stabize the lens to extract max. potential, but I would first like to see what it can do by using what most would likely use as a supported tripod set-up. I'd also like to see how it does on a Wimberely, regardless how unconventional it might be for such a camers/lens combo. I'd be more than happy to share my findings regarding use of this lens.

    Thanks for your comments regarding use of the 1.4x with your 400 f5.6. Interesting! Your observations confirm my initial concerns regarding both stability and reliably being able to capture images with appropriate sharpness. From the sound of it, you have a good handle on it. Those slow shutter speeds as you mentioned, can be truly problematic and I've encounted them numerous times.

    Correct me if I'm wrong, but I think many have commented that it is only the late production (SMCP) 55mm 67 lenses that are excellent performers, even on the 645D, whereas the earlier 55mm Takumar's were not. I'm not certain which vintage yours is.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Dave, I have the latest 67 55mm, but, of course I am comparing only my copies of those lenses. I tested the 645 55mm last February shooting a bookcase at 10 ft and was not very impressed, since then I retested at longer distances vs the 67 55mm and have been surprised by the lens. I'll let you draw your own conclusions, but I see less purple fringing and a little more crispness with the 645 lens (more CA as well), but the 645 lens is much smaller and a stop faster. Actual pixel crops.

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Hi Tom,

    Simply commenting on your two posted crops (above)....obviously there is considerable CA in the left hand crop while it may have the ever so slightest advanatge of higher contrast. The image on the right is of course warmer. In terms of detail/sharpness, it's a wash. All in all of course I'd pick the lens on the right side. Thanks for posting this comparsion.


    Dave (D&A)
    Last edited by D&A; 16th March 2012 at 20:20.

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Thanks for posting this in-depth info Dave. Did you have any opportunities to test Pentax 67 lenses on the 645D? If so, any observations you could share?

    Gary

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    You're most welcome Gary! I initially started to test a few 67 lenses on the 645D, but at the present found too few samples of most of the focal lenghts to make any sort of definitive conclusion. I think there is good potential fro my initial observations and know some 645D shooters that have made good use of certain 67 lenses, especially the more exotic ones where there is no 645 counterpart. Apparently, in some cases, whether a given 67 lens is an older SMCT or a newer SMCP, can often make a difference. On other cases not so much.

    Of course with your nice collection of 67 lenses, if you provide a RT ticket to your beautiful area of the country (and a hot cup of coffee to keep me warm), I'd love to bring my 645D body up there so we can both test out your 67 lenses

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    We could give them a pretty good workout, for sure. All of my P67 lenses are the latest SMCP models and I have the Pentax 67 to 645 lens adapter.

    Bought my 645NII a year ago and pulled together a small collection of 645-A manual focus lenses with the thought/hope of someday getting a 645D. That hasn't happened yet, but one never knows (I just noticed Roy's 645D for sale).

    I also have a Hasselblad V to Pentax 645 lens adapter, so we might as well put my collection of Hasselblad Zeiss glass to the test too.

    There are espresso stands and good coffee shops all over this part of Alaska.....so keeping you topped off with hot coffee won't be a problem.

    Maybe we could get Jack and Guy to schedule a GetDPI workshop in Alaska next year (Prince William Sound, Denali National Park, etc?)....which would provide an added excuse/opportunity for you to come up to Alaska.

    By the way.....I'm glad to hear that the P645 120 macro performs so well on the 645D. It is my favorite lens for use on the 645NII.

    Gary

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by bensonga View Post
    We could give them a pretty good workout, for sure. All of my P67 lenses are the latest SMCP models and I have the Pentax 67 to 645 lens adapter.

    Bought my 645NII a year ago and pulled together a small collection of 645-A manual focus lenses with the thought/hope of someday getting a 645D. That hasn't happened yet, but one never knows (I just noticed Roy's 645D for sale).

    I also have a Hasselblad V to Pentax 645 lens adapter, so we might as well put my collection of Hasselblad Zeiss glass to the test too.

    There are espresso stands and good coffee shops all over this part of Alaska.....so keeping you topped off with hot coffee won't be a problem.

    Maybe we could get Jack and Guy to schedule a GetDPI workshop in Alaska next year (Prince William Sound, Denali National Park, etc?)....which would provide an added excuse/opportunity for you to come up to Alaska.

    Gary
    Wow, is all I can say to all your posted possibilities. I knew you had quite a few 67 lenses, but didn't know they were all the newer SMCP! Combine that with your adapters, especially the Hassy one to go along along with your Hassy lenses, and yes, we'd definitely have something to talk about (and a heck of a lot of test files to go through). Interesting about those A 645 lenses. Some are of the same optical design as their FA (AF) counterparts, some not and it's already been demonstarted that a few to say the least have certain advanatges over their AF counterparts.

    Lastly, scheduling a workshop there would be a temptation that would be hard to resist. Now all I need to do is win the lottery! Please don't tell me though that I can pick up the winning ticket at any nearby Alaskan convienience store...LOL!

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Sad to admit, but I have too much gear and not enough time or skill to use it properly. Someday, I hope to rectify both of those problems.

    There is one question re using the Pentax 67 lenses on a P645D which I've often wondered about. Perhaps you can clear this up for me. I risk showing my ignorance of basic principles of optics or whatever here, but so be it.

    If we mounted a Pentax 67 55mm lens on a 645D, would it give the same FOV etc as a native Pentax 645D 55mm lens? The widest P645 lens I have is the 75mm f2.8. But for the P67, I have the 45mm and 55mm lenses also, so rather than buying some of the wider P645 lenses, I've just been using my P67 45 and 55mm lenses on my 645NII for now....but I wasn't sure if they were in fact equivalent to the P645 lenses. Like I said....it may be obvious, but I'm just not sure.

    To tempt you further....I have the P67 75mm shift lens we can try on the 645D too. That might be fun.

    Gary

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Hi Gary,

    Unless I'm mistaken (and no doubt I am more times than I care to admit), the 55mm Pentax 67 lens will give the same FOV when mounted onto the 645D as if you mounted a 55mm Pentax 645 lens on the 645D. Same thing would apply if you mounted your 55mm Penatx 67 lens onto your 645NII. It would give the same FOV as a 55mm Pentax 645 lens mounted to that same 645NII.

    Well now that you mentioned you have the P67 75mm shift lens, I've already started packing my bags and on my way. Start charging those batteries....oh wait, it's me that has to do that (for the 645D)....LOL!

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Thanks Dave! Not sure why I couldn't get that clear in my head, but for some reason, I just wasn't sure.....always second guessing myself on it.

    I figured that 75mm shift lens would be the decisive factor.

    Maybe by the time you get here....I'll finally have a 645D too, so we can really put those lenses thru the ringer. If I could just bring myself to sell off some of the gear I may never use again, I might be half way there.

    Gary

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by bensonga View Post
    Thanks Dave! Not sure why I couldn't get that clear in my head, but for some reason, I just wasn't sure.....always second guessing myself on it.

    I figured that 75mm shift lens would be the decisive factor.

    Maybe by the time you get here....I'll finally have a 645D too, so we can really put those lenses thru the ringer. If I could just bring myself to sell off some of the gear I may never use again, I might be half way there.

    Gary
    Hi gary,

    Thats the hard part....selling off gear that we loved using or have a strong attachment to. The Pentax 645D was a excellent and competitve 1st time entry into medium format digital for Pentax and obviously with all the delays and constant update to the body prior to it's release, most definitely worked in it's favor.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by tsjanik View Post
    Dave, I have the latest 67 55mm, but, of course I am comparing only my copies of those lenses. I tested the 645 55mm last February shooting a bookcase at 10 ft and was not very impressed, since then I retested at longer distances vs the 67 55mm and have been surprised by the lens. I'll let you draw your own conclusions, but I see less purple fringing and a little more crispness with the 645 lens (more CA as well), but the 645 lens is much smaller and a stop faster. Actual pixel crops.
    Tsjanik, in my experience the SMC 67 55 is an extraordinary lens. It is not possible to see any difference with any other lens because it out resolves (at least my copy) the 645d center to corner full open.
    This image is a 100% crop and there is revealing moire all over the roofs. The shot is taken from a distance of approx. 3 km.
    By the way, focusing is a problem. I use the lens to infinity, so determined correct focus with a series of trials and than blocked the position with adhesive
    paper.


    _IGP0023crop by sergio lovisolo, on Flickr

    Sergio
    Likes 1 Member(s) liked this post

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Dave: Thank you so much for the tremendous amount of work obviously put in to this. I have printed this out, and it will become my "Bible" for 645D lenses!
    Again....thanks
    Dave in NJ

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by sergio lovisolo View Post
    Tsjanik, in my experience the SMC 67 55 is an extraordinary lens. It is not possible to see any difference with any other lens because it out resolves (at least my copy) the 645d center to corner full open.
    Sergio
    Serigo, yes the 67 55mm has an outstanding reputation, and I am not saying that is undeserved but rather that the 645 55mm is underrated and that at least for my copies of these lenses, the 645 lens has less purple fringing and maybe a little more contrast.

    Tom

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by gurtch View Post
    Dave: Thank you so much for the tremendous amount of work obviously put in to this. I have printed this out, and it will become my "Bible" for 645D lenses!
    Again....thanks
    Dave in NJ
    Dave, thank you ever so much for your kind words...they're greatly appreciated! Your contributions in providing both your experiences with the 645D and especially your posted images, have always been an inspiration. Thanks again!

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by tsjanik View Post
    Serigo, yes the 67 55mm has an outstanding reputation, and I am not saying that is undeserved but rather that the 645 55mm is underrated and that at least for my copies of these lenses, the 645 lens has less purple fringing and maybe a little more contrast.

    Tom
    Hi Sergio and Tom,

    Both of your personal experiences and images with Pentax 67 lenses on the 645D illustrate the similarities of issues encountered, are much akin to those I posted with regards to Pentax 645 lenses. Namely these were film era lenses and the presumption is that adjument and acceptable tolerance in lens performance prior toleaving the factory, had considerable acceptable variation for their intended use with cameras at the time of manufacture.

    Some lenses like the Pentax 120 f4 645 macro were extremely consistent, while others not so much. When a "good" lens sample is found for many of these Pentax lenses, we all have been impressed with their performance on the 645D.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    You are quite welcome, Dave. You always seem to go out of your way to say something positive to other people's posts. I am 75 years old, in my day that was referred to as being a gentleman, which you are.
    Best regards from cool, foggy, Rainey NJ
    Dave in NJ

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by gurtch View Post
    You are quite welcome, Dave. You always seem to go out of your way to say something positive to other people's posts. I am 75 years old, in my day that was referred to as being a gentleman, which you are.
    Best regards from cool, foggy, Rainey NJ
    Dave in NJ
    I feel we have a great bunch of people here, always willing to both praise and provide constructive criticism. Both are important for making evaluations and learning. Thanks!

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Dave, thanks for such an incredible resource. My 645 experience is limited but some day that might change. When it does, this will be especially useful!
    Listen to my new album "The Drones" free on BandCamp. Visit my Flickr images, website, or blog. Cheers!

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by D&A View Post
    I feel we have a great bunch of people here, always willing to both praise and provide constructive criticism. Both are important for making evaluations and learning. Thanks!

    Dave (D&A)
    Right you are Dave, this is a great forum. In contrast, I noticed your post on another forum where the replies are not just unappreciative but boderline hostile.

    Tom
    Last edited by tsjanik; 19th March 2012 at 14:46.

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by tsjanik View Post
    Right you are Dave, this is a great forum. In conrast, I noticed your post on another forum where the replies are not just unappreciative but boderline hostile.

    Tom
    Yes Tom, I saw them also. I think some people lose their manners as soon as they go on-line. There was another contributor over there that did a ton of early work and evaluations when the 645D first came out (he imported one from Japan). He posted his findings, and to say the least, the responces were unappreciated, and rude. "No good deed goes unpunished"
    Dave G

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Great review and massive amounts of hard work - thank you!

    I also have a 645D, and the following lenses:
    67 lenses (all latest versions): 55f4, 75f2.8AL, 90f2.8, 90f2.8LS, 105f2.4, 135f4macro, 150f2.8. 165f2.8, 200f4, 300f4EDIF.
    645 lenses: 35A (manual focus), 55f2.8DFA (latest digi version), 150FA and the 45-85FA

    I also have a Blad 6x6 adaptor (but no such lenses)!

    Please let me know if these can of any help to you in further tests (as long as you fly to Australia or tell me how I can do tests for you!).

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Dave (D&A): I also have a near mint 300mm A* lens and "New Old Stock" 1.4X extender. It really is new: box, papers, warranty card, etc. If you would like to borrow both for testing, it would be my pleasure.
    Dave in NJ

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    **(Reviosions made to the post below)

    Hi Everyone,

    I'll attempt to address some of the recent posts above in a single posting, in order to make things a bit more concise:

    1. Hi Robin...your kind words are appreciated. I too find when I come across some useful information regarding lenses or equipment...that I might not be shooting with what is being reviewed at the time, but never less, the information down the road often becomes a guide, so that I can make informative choices. Contributions by everyone, like here in GETdpi, truly facilitate this concept.

    2. Tom, if I am thinking of the same postings as you were regarding some of the thoughts others posted on a different forum, I'm not sure how hostile they were vs. simply having a different yet strong opinion about certain things. I'm refering to the questioning of aperture I selected for the sweet spot of some of the lenses. The term "sweet spot" as I explained is very subjective....some would say it's the earliest f-stop where max sharpness is generally obtained over most of the frame (ie: max sharpness in the central part of the frame is reached), even though the edges and sides might not be up to the level of the central art of the image. Others, like landscape shooters might say it's the earliest f-stop where optically the lens reaches max sharpness from edge to edge right into the corners. The sweet spot of a given lenses aperture for one type of shooting (or shooters) may differ from those who's objectives in image reproduction is different.

    The point is as you well know, differing opinions is both welcome and healthy. Its how we all learn and build up a base of information....but only as long as its done both constructively, with respect for others and of course without malice.

    3. Ed, you have some very interesting lenses I'd love to test. I was hoping to get around to the 67 lenses on the 645D, but have to obtain sufficient quantities in order to have a meaningful # of samples. Wow, I'd love to visit Australia and at the moment, don't have my glasses on...did you type you'll be sending me a R/T ticket to your local this week so we can shoot...LOL! I'll keep an eye on my mailbox and start packing (don't I wish)! I appreciate your offer and suggestion and maybe one day I'll get lucky enough to accept. In the meantime your observations with your lenses would be most interesting.

    4. Dave (in N.J.)...you have the one lens I've been dying to evaluate and compare to the Fa 300 f4. Namely that's the A* 300 f4. It seems some of the manual focus 645 lenses, whether they are the same optical formula as their Af counterparts or not, may have optical advantages over the same focal lengths in 645 Af lenses. Interestingly, this same thing occurred many years ago when Pentax started making Af 35mm lenses. Many of the older manual focus lenses were optically superior. As you know the MF 35mm f3.5 may have some advantages over the Fa 35mm f3.5...namely less spherical curvature (field curvature). This gives rise to a flatter optical field and therefore, distant landscapes seem to be somewhat sharper across the entire image when compared to the Fa version of the same lens.

    Instead of sending the lens, I am hoping that I might be spending a short time (vacation) sometimes this summer in the general vicinity of Cape May. If that happens, who knows, maybe we'll be able to meet up and can do a bit of shooting with both the A*300 f4 and the FA 300 f4 (with and without the 1.4x, which I also have). It would be an interesting comparison.

    What I am really after is to get caught in nice steady rainstorm where I can head over to that spot with the bird on the wooden pier which was near a dock....the exact location where you took your astonishing impressive 645D image of such a subject (which you posted not long ago on Getdpi)...and try to emulate the same shot. Of course nothing I photograph will come close to your original! We'll see what happens as simmer approaches.

    Thanks all!

    Dave (D&A)
    Last edited by D&A; 20th March 2012 at 16:15.

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Just a quick comment. After posting my comments above, I've added/deleated some comments, it case it was read shortly after initially posting. Thanks.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Dave (D&A): by all means!!!! We love Cape May, in fact we are going there end of this month for our "Cape May fix". Cape May is exit 0 on the Parkway, and we are exit 63, so we are close. I would also love to show you all our favorite photo spots on LBI. My web site has our home phone number.
    Best regards
    Dave
    Web site:
    MODERN PICTORIALS.
    Ps also have the following manual focus lenses:
    35 mm
    75mm
    120 macro
    150mm
    200mm
    45-85mm

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Wow Dave (in N.J.), that sounds wonderful and very much appreciated. Although I sometimes travel up to the Northeast (on I 95 of course), I only once got to see Cape May for an evening around holiday time years ago. Everything I hear about it and the surrounding areas always soud like a wonderful place to visit and "catch ones breath" for a nice stay. I assume LBI is for Long Beach Island (or something close to that?) That must be a very nice aea too in the summertime I would imagine. As summer approaches, I'll know more regarding travel plans, but all sounds really nice.

    What's interesting is you have the manual focus equivelents of many of the Af lenses I have and tested...some being the same optical arrangements, and others somewhat different. Hmmm, and lets, see besides similar lenses you the same camera (645D)...so I wonder then why your images are so often dramatic and spectacular while mine still often need that little something else.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Yes, Dave, LBI is Long Beach Island. The photo you referred to is Polly's Dock, about 4blocks from where we live. It is a real throw back. While bay and beach front mansions go up, Polly's is still unchanged. On my web site I devote an entire page to it (see Polly's Dock page), because I am afraid it will go away to make room for mansions, condos, etc. I have made it a point to photograph it in all kinds of weather.
    I also have AF lenses which in some cases duplicate the MF lenses. I have been meaning to shoot them side by side with their equivalent AF lenses, and compare. Alas, even though retired, there just is not enough time in the day for all my interests. Also, do not want to cut into our "Happy Hour " time every evening!
    Dave

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    LOL Dave, there "is" never enough hours in the day to really get what we want done....and now I'm finding it doesn't ever change no matter how old one gets! (speaking for myself of course).

    Yes, it was your photo I believe at Polly's dock during a rain strom that was one of my favorites of yours (although there were many that I found impressive). I'd love to see that area too (besides Cape May).

    When its not so late here, I'll have to go back to your website and read about Polly's dock and the surrounding area. Things change quickly in this world and there is a scene of a lone old storage barn for hay (is that what it's called?) on a rolling hillside...dotted with cattle of course (for this "orginally from NYC" guy to gaze at) while I mavel at the scene and the yearly changes it goes through. The Blue Ridge mountains sets the backdrop. It's a regular stop of mine on the side of the road, to capture it in all it's tranquil splender through all sorts of weather and the change of seasons. Besides an often used informal test image which I then can compare the same images captured, taken with different cameras. I feel at some point that certain changes are in the wind and before I know it, this lovely scene will give way to progress. Thats why so many fo us retrun to our favorite subject, over and over. It's like visting and taking a portrait of an old friend. I bet Polly's Dock has a 1000 different looks depending on the weather, time of day and of course the season and it's always comfortuing to know it's there.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Dave: Another Icon is "the Causeway Shack" It holds a special place in the hearts of those that used to come to LBI for vacation. It meant "We are almost there". It slowy has fallen down, and it is just about gone. Fortunately I started photographing it way back when, and continue to do so. If you visit my web site there is a special page dedicated to shack images of mine over the years, the page is called Causeway Shack Images. Several were shot a long time ago with my original Pentax 645 and Kodak color negative film. I made 16"x20" color darkroom prints from the negs. I scanned the negs and now have big digital prints.
    Sample Images here:
    Last edited by gurtch; 5th September 2013 at 08:18.
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  38. #38
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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    All four of the above shot with Pentax 645, don't remember which lenses. Back then I had 35mm, 55mm, 75mm and 150mm.
    Dave in NJ

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Hi Dave (in NJ),

    Its a bit uncanny...The shack you have been documenting for years in many ways reminds me of the hay barn I described in my post above. I name my files of it "Shed on a Hill". Try to imagine your shack on a hillside with small-moderate mountains in the distance. Almost like that visual image of the house on the hillside from the Sound of Music where the song "The Hills are Alive" starts playing . I've photographed my shed for years, though the changing seasons and ever changing landscape. I think most of us who photograph, get attached to some "subject" that represents the passing of "time" and we often stop to document it. I presume for you one of those items is your Shack...for me it's my Shed on the Hill.

    Love the last of the four shots with the sunset and birds....stunning Dave!

    Like my posting of the lens tests above, where I was delayed, so too am I delayed with posting some 645D images. I hope to address that soon with a few.

    There never is enough hours in the day so the first political candidate that promises to extends each day to 28 hours...gets my vote!

    Dave (D&A)
    Last edited by D&A; 22nd March 2012 at 08:17.

  40. #40
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    The FA 35mm lens "blur zone"

    Hi Dave, Yes I am another one independently found the regional "blur zone" problem and very very puzzled since. My feeling is the location of such selective blurring is rondom so I doubt it is related to the resin layer shape imperfections.

    What's your recent take on this issue, or have you heard from other people on the problem? Very interesting, and might be related to the way data are read out? If so why only the 35mm FA? Does the A version has the same issue? Could it has relations to what digLloyd just reported on Nikon D800/D800E, the regional "starcasing"?

    Anyway a topic needs some deep poking. Thanks again.

    Leping

    Leping Zha Landscape and Infrared Photography

    Quote Originally Posted by D&A View Post
    Pentax FA 645 Lenses

    1. FA 35mm f3.5 (28mm) . This very popular lens is an excellent performer under most but not all shooting conditions. Itís performance varies greatly depending on subject distance, f-stop employed and whether the subject is greatly affected by the extensive spherical curvature this lens exhibits primarily at long camera to subject distances. I tested out more samples of this lens (greater than 10), than any other FA lens. The spherical curvature appears small at relatively short distances but quickly grows as the focusing distance increases. At typical landscape distances, many samples display enough spherical curvature so that edges/corners are softer than the central portion of the frame. If one though looks though at the edges/corners (such as the lower right and left ones) that are in the foreground of an infinity focused landscape, these corners are often sharp compared to the upper right and left corners at infinity. This is a result of this spherical curvature. Camera/lens angle and distance to the subject can also greatly influence this. Some barrel distortion is evident with this lens, but nothing thatís not easily correctable in post processing.

    ** One sometime strange observation Iíve observed with this lens is what Iíll refer to as a ďblur zoneĒ. Iíve noticed it in almost all samples (although not in all images with a well defined consistency) an area of the image where all detail in the subject is slightly blurred. Everything above/below and around that zone is sharp and itís certainly not due to movement of subject (unless a small area of an entire brick wall moved!). Iíve seen this at a wide variety of focus distances. Itís more prevalent at the wider apertures and decreases to an extent when stopped down. It comes and goes and I yet donít have a handle on a well defined set of parameters to ensure 100% of its appearance. Recently some other FA 35mm f3.5 lens shooters also independently noted this strange anomaly as well as one individual with their MF 35mm A 645 lens. If I had to describe it, it looks like a small group of tree leaves in an entire image of trees together with their leaves, had moved in the wind during exposure....while the rest of the entire mass of trees with their leaves contained in the rest of the image are perfectly sharp. Could it be due to the slightly uneven pouring of the resin used to make the aspherical containing lens element? Purely conjecture at this point and its rarely observed.

  41. #41
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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Just to muddy the waters, I have seen something a little like this on my 55 f2.8 (latest version) but I am not sure this is not due to element alignment. It is being serviced right now, so I will know more over time.

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Hi Leping and Ed,

    I apologize for not seeing both your postings above. I haven't looked at this thread in a few weeks and wished I had seen your comments sooner. All very interesting! I haven't investigated the issue of the "blur zones" any further with regard to the FA 35mm 645 lens although a few other individuals did contact me and report they observed this too with their lenses. I suspect that some others have lenses with such optical anomalies but haven't looked for them specifically or don't even know about them. In fact I suspect most of the FA 35mm lenses have some degree of this.

    I don't think the location of a blur zone is that random in a given sample of lens but just appears that way since I did observe that the location(s) and even size of a blur zone can change depending on the focusing distance the lens is set to. In other words, camera to subject distance. At times, especially with landscapes, a blur zone may fall in a relatively smooth area like a sky or in the deep shadows and it is easily missed. I still hold onto the theory that it is related to the pouring of the resin that is responsible for making the aspherical element. Of course I could be totally wrong.

    As for reports of these blur zones in the A* 35mm 645 lens...I never noticed any in my short time with the lens but one person did tell me he thought he saw it in his lens...but that has yet to be confirmed.

    Ed, very interesting that you mentioned something like that observed in your Af 55mm f2.8 645 lens. When I tested the samples of that lens, I thought I saw one blur zone on a small scale but had trouble replicating and finding it again on subsequent shooting on a different day with that lens. The other sample didn't appear to have that issue. I'll be interested to hear what Pentax says. Please keep us posted.

    Thanks again for these interesting observations and thoughts!

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Having trawled through this, I'm eternally grateful to Dave for doing it, and GetDPI for being the place where someone would post such info.

    However, I'm still left wondering how I would put a kit together. I am coming from a Hasselblad H4D 40 with 35-90, 150 and 210 lenses. These are all excellent lenses, and it never occurred to me that there may be much in the way of inter-unit variation.

    My initial thought for a replacement was to buy a D800E with Zeiss glass, and a Nikon or two for AF. I then remembered the 645D. Having had a 645NII in the past, the attraction was very strong. I also loathe 3:2 ratio.

    When I read the reviews, the words 'stellar' or 'excellent' seem to be missing. Additionally, inter-unit variation seems to exist often. I really don't want to get into buying and selling until I get a good lense.

    Am I misreading this, or is that just the reality of Pentax today?
    Cheers,
    Jeff
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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Hi Jeff:

    Iíve used many 645 and 67 Pentax lenses on the 645D and have followed the development of the camera and later lens reports (I supplied Lloyd Chambers with two of the lenses he tested). I can say without hesitation, based on my experience and all the reports Iíve read, that the 35mm A, 45-85mm, 75mm, 120mm, 300mm (645or 67) and 400mm will not disappoint you. I would classify the 35mm, 75mm, 120mm and 400mm as stellar. Some examples from the 35mm and 120mm (full and crop)


    Tom
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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Thanks Tom, any chance of getting the RAW files for those?
    Cheers,
    Jeff
    www.jeff-grant.com

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Quote Originally Posted by Jeffg53 View Post
    Having trawled through this, I'm eternally grateful to Dave for doing it, and GetDPI for being the place where someone would post such info.

    However, I'm still left wondering how I would put a kit together. I am coming from a Hasselblad H4D 40 with 35-90, 150 and 210 lenses. These are all excellent lenses, and it never occurred to me that there may be much in the way of inter-unit variation.

    My initial thought for a replacement was to buy a D800E with Zeiss glass, and a Nikon or two for AF. I then remembered the 645D. Having had a 645NII in the past, the attraction was very strong. I also loathe 3:2 ratio.

    When I read the reviews, the words 'stellar' or 'excellent' seem to be missing. Additionally, inter-unit variation seems to exist often. I really don't want to get into buying and selling until I get a good lense.

    Am I misreading this, or is that just the reality of Pentax today?
    Hi Jeff,

    Am currently at work so I apologize if my response at the monment is brief. Tom mentioned some of the exceptional performing lenses in the 645 system that do well on the 645D body and I can certainly elbaorate my actual own personal experiences with them. As for sample to sample variability as posted in my comprehenisve lens testing, it's important to note a few things. Everyone's level of acceptability of a particular lens sample performance varies as to what is acceptable or not. Variations exisit and to what degree depends on which lens is being refered to. It not all that unlike some other medium format systems where sample differences could also be seen to varying degrees.

    Another factor to consider is intented use and output. If it's for large sized large format printing, then of course differences often seen in lens samples may and can often be quite noticable. There are some cases where it didn't take a 24x36 inch print to relaize these differences. How important they are to ones actual work is of course both subject dependent as well as how exacting a lens performance is to the individual.

    With all this said, I don't want you to get the impression that you have to go on a "looking for a needle in a haystack" approach to find good lenses for the 645D...on the contrary. Just keep in mind some of the findings I posted and for key focal length lenses that you will use primarily, take the usual precautions in purchasing a particualar sample lens. It's not very different than those who shoot Nikon and look for and expect a properly aligned and exceptional performaing sample of a high performance lens for that system. As you can see in the Nikon formums, even the best most expensive glass often has considerable variation and some look for a "good" sample. The recent Sigma 35mm f1.4 is a good example.

    Keep in mind that many of these Pentax 645 lensees were designed in the film era, so they didn't require the as precise tolerances that are required by high performance digital cameras of today. Even Pentax and other Medium format digital manufacturers noted this when their users would try and use legacy film era lenses.

    With all this said, maybe the key think to note with te 645D is AF fine tuning of each lens purchased. I found this was more important than anything else to exact the best possible performance from 645 lenses on the 645D. I am so thankful Pentax included this feature on the 645D.

    After having shot with both the D800e as well as the 645D, I personally feel there is a substatial difference in the look of the files, espcially when printed large and there is a strong case for shooting with MFD in the 40MP range. Each system has it's strengths and weaknesses and I would venture a guess that the very reasons you or someone else enjoyed shooting with the hassy system over 35mm DSLR's would again find the same advantages shooting with the 645D. The system is an exceptional value and is one of the reasons is still extremely popular. Again these are simply my own personal views.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Hi Dave,

    Many thanks for that. I guess that my background is confusing me in this discussion. I expect to be able to wander around at 100% and see the same across a frame. The HC lenses that I had all deliver that kind of performance. When I read this post, I started to wonder, and worry.

    I hear you loud and clear about MF vs D800E. That's why I'm looking before I leap. I don't want Phase. I'm really over big, heavy cameras. I'm just too old for it. I love my old 645NII and have started looking at it as a possible way of getting MF performance with less weight.

    When I started looking at lenses, I could only find three for sale at B&H, the 55, 45 and 90. Is that it. Do I have to buy anything else used?
    Cheers,
    Jeff
    www.jeff-grant.com

  48. #48
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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    HI Jeff,

    There are three "digital Specific" 645 lenses currently being produced by Pentax...the 25mm, the 55mm and the newest, which is the 90mm. Apparently the word is Pentax still has in production on a limited basis many of their legacy 645 lenses but generally when found new, can cost an arm and a leg (in some cases). Buying used with regards to Pentax 645 legacy lenses isn't such a bad thing. Many haven't been used very much and certainly no wheres near the extent that 35mm glass is...so some genuine "good buys" can be found.

    I should have mentioned in my previous response that all of my lens tests and comments reflect on examining each test file at actual pixels (100%), so I definitely pixel peep when it comes to lens evaluations.

    As for edge to edge sharpness with each lens, it can certainly vary and some focal lengths are noted to be stronger than others. Generally though an optimal sample of a given "good" lens will show more than adaquate sharpness across the frame with the emphasis on the highest resolution more towards the central part. In practical use this of course isn't an issue in most cases nor noticed in most types of imagery.

    One thing that might set apart some of the Pentax 645 lenses (both legacy as well as some of the digital specific ones), is they exhibit a very film like quality on the 645D as opposed to ultra biting digital sharp images. This may be a consequence of slightly less microcontrast and in my opinion lens a very nice quality to the files, especially when printed. This also sets apart the 645D from many traditional current 35mm DSLR's in my opinion.

    Dave (D&A)

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Thanks Dave, film like is most appealing. That's one of the very appealing things about the OM D. I still shudder when I read 'optimal sample' 'can certainly vary' but I'll go away now and do a bit more research. Thanks for all your hard work on the Pentax lenses. It's been enormously helpful.
    Cheers,
    Jeff
    www.jeff-grant.com

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    Re: Comprehensive Testing: Results & Observations with Pentax 645 Lenses used on the

    Thank you for the really useful thread for someone like me contemplating a move to the 645z. Just a question for Dave. Have you ever completed the test of the A-600mm with the 645D? What are the results? Thanks

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