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Thread: AFD MTFs?

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    AFD MTFs?

    Does anyone know if there are any MTF charts available for the new Hy6 AFD lenses? I'd love to see one for the AFD 180/2.8, for example.

    It's hard to get enough information to find out if they are worth the price premium, but I think a Rollei MTF (my understanding is these MTF charts are produced from real lenses, not the theoretical design) would tell me everything I need to know to figure out if the AFD's are worth the price premium over the previous-generation AF lenses.

    Thanks in advance,
    Brad

  2. #2
    thsinar
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    Re: AFD MTFs?

    hi Brad!

    I will try to get something for you. Not sure if I will succeed, but I'll try.
    Give me some time.

    Best regards,
    Thierry

    Quote Originally Posted by BradleyGibson View Post
    Does anyone know if there are any MTF charts available for the new Hy6 AFD lenses? I'd love to see one for the AFD 180/2.8, for example.

    It's hard to get enough information to find out if they are worth the price premium, but I think a Rollei MTF (my understanding is these MTF charts are produced from real lenses, not the theoretical design) would tell me everything I need to know to figure out if the AFD's are worth the price premium over the previous-generation AF lenses.

    Thanks in advance,
    Brad

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    Re: AFD MTFs?

    Thank you, Thierry! (again!)

    I'll check back with you in a couple of weeks or so.

    Much appreciated!
    -Brad

    Quote Originally Posted by thsinar View Post
    hi Brad!

    I will try to get something for you. Not sure if I will succeed, but I'll try.
    Give me some time.

    Best regards,
    Thierry

  4. #4
    thsinar
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    Re: AFD MTFs?

    Brad,

    I have just checked and found the little book that comes with each lens and which I have. I have found inside the Schneider AF 2.8/180 MTF chart.

    I have made a quick copy of it with my Lumix, so sorry if the quality is as it is, but at least you can read it.

    Best regards,
    Thierry

    Quote Originally Posted by thsinar View Post
    hi Brad!

    I will try to get something for you. Not sure if I will succeed, but I'll try.
    Give me some time.

    Best regards,
    Thierry

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    Re: AFD MTFs?

    Quote Originally Posted by thsinar View Post
    Brad,

    I have just checked and found the little book that comes with each lens and which I have. I have found inside the Schneider AF 2.8/180 MTF chart.

    I have made a quick copy of it with my Lumix, so sorry if the quality is as it is, but at least you can read it.

    Best regards,
    Thierry
    Thierry,
    I believe Brad was asking for the AFD MTF charts. The chart you presented is the AF 2.8/180 version. But technically you are correct they are the same. I just want to clarify for Brad sake.

    Brad,
    I had both the 2.8/80 AF and AFD and there seems to be no differences. There are differences in some of the focal length between the MF versus the AF for example the MTF chart Thierry showed here (AF) of the 180 mm has less distortion than the MF (manual focus) 2.8/180 lens; both are Schneider lens. The MTF chart on the AF 2.8/50 has better resolution than the MF 2.8/50 (I am selling this one in favor of the 55 PC). But don't let only this MTF factor alone daunt you from liking the MF lens. I find that the MF lens has such amazing mechanics especially the precision of the finest focus mechanism. When I shoot I choose manual focus on the big bright medium format focusing screen to focus for composition instead. Thus, almost all of my lens are now in MF version. Thus, the two lens that are worthy in my book to be in AF is the Schneider Super Angulon HFT 2.8/50 PQS and the Schneider Tele-Xenar HFT 2.8/180 PQ. In addition, I do not believe the AFD is any difference from the AF with the exception of quality control may be even tighter. However, Rollei optics quality control has always been one of the best manufactory along with Sinar. Thus, this is one of the many positives of going with the Rollei/Hy6 systems is that the optics are reliable and were ahead of their time. Remember that not all digital optics are the lens of choice. An example of this is how Jack Flesher and Guy Mancuso (I give full name here for those that are new and do not know Jack and Guy and thus they deserve the credit here and Theirry as well for his time and effort to educate folks about Sinar system) lead the way with using older Leica M optics and how that influence folks to join them similar to the latest medium format wave right here at Get DPI forums. You can read more into their reason for going with the older Leica M lens. I find that the Rollei lens on the Hy6/Rollei 6008 reminds me much of the Leica M system.

    Best Regards,
    -Son

    Best
    ALPA (MAX, STC, TC) | CAMBO (Actus DB2, WRS-AE) | CONTAX | HASSELBLAD | LEICA | DB (CFV-16, CFV-39, IQ180, IQ360, IQ3100, P45+) | Lens (Canon, Fujinon, Leica, Nikon, Pentax, Rodenstock, Schneider, Zeiss)

  6. #6
    thsinar
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    Re: AFD MTFs?

    Yes I know, Son: but those don't exist yet.

    And Brad said that he would take as well the "AF" ones.

    And yes, I expect them to be the same, since it is the same optical design.

    If somebody needs some other charts from the other existing Zeiss or Schneider AF, I can do the same, make a quick and dirty copy and post it.

    Thanks Son,
    Thierry

    Quote Originally Posted by Pham Minh Son View Post
    Thierry,
    I believe Brad was asking for the AFD MTF charts. The chart you presented is the AF 2.8/180 version. But technically you are correct they are the same. I just want to clarify for Brad sake.

    Brad,
    I had both the 2.8/80 AF and AFD and there seems to be no differences. There are differences in some of the focal length between the MF versus the AF for example the MTF chart Thierry show here (AF) of the 180 mm has less distortion than the MF (manual focus) 2.8/180 lens; both are Schneider lens. The MTF chart on the AF 2.8/50 has better resolution than the MF 2.8/50 (I am selling this one in favor of the 55 PC). But don't let only this MTF factor alone daunt you from liking the MF lens. I find that the MF lens has such amazing mechanics especially the precision of the focus mechanism. Almost all of my lens are now in MF version. Thus, the two lens that are worthy in my book to be in AF is the Schneider Super Angulon HFT 2.8/50 PQS and the Schneider Tele-Xenar HFT 2.8/180 PQ. In addition, I do not believe the AFD is any difference from the AF with the exception of quality control may be even tighter. However, Rollei optics quality control has always been one of the best manufactory along with Sinar. Thus, this is one of the many positives of going with the Rollei/Hy6 systems is that the optics are reliable and were ahead of their time. Remember that not all digital optics are the lens of choice. An example of this is how Jack Flesher and Guy Mancuso (I give full name here for those that are new and do not know Jack and Guy and thus they deserve the credit here and Theirry as well for his time and effort to educate folks about Sinar system) lead the way with using older Leica M optics and how that influence folks to join them similar to the latest medium format wave right here at Get DPI forums. You can read more into their reason for going with the older Leica M lens. I find that the Rollei lens on the Hy6/Rollei 6008 reminds me much of the Leica M system.

    Best Regards,
    -Son

    Best

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    Senior Member PSon's Avatar
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    Re: AFD MTFs?

    Thierry, if I have a company myself you would be the top priority on my list to hire; your professionalism is much appreciated not only myself but all the folks who decided to go with Sinar system.

    Best Regards,
    -Son
    ALPA (MAX, STC, TC) | CAMBO (Actus DB2, WRS-AE) | CONTAX | HASSELBLAD | LEICA | DB (CFV-16, CFV-39, IQ180, IQ360, IQ3100, P45+) | Lens (Canon, Fujinon, Leica, Nikon, Pentax, Rodenstock, Schneider, Zeiss)

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    Re: AFD MTFs?

    One final comment from me:
    For those that never had experienced with the Rollei lens but had great exposure and appreciation for the Leica M and some R lens, the manual focus (MF) mechanism of the Rollei lens is as great or even to a higher level.

    -Son
    ALPA (MAX, STC, TC) | CAMBO (Actus DB2, WRS-AE) | CONTAX | HASSELBLAD | LEICA | DB (CFV-16, CFV-39, IQ180, IQ360, IQ3100, P45+) | Lens (Canon, Fujinon, Leica, Nikon, Pentax, Rodenstock, Schneider, Zeiss)

  9. #9
    thsinar
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    Re: AFD MTFs?

    Thanks Son, much appreciated. I am a very demanding person, also with myself, that makes me sometimes spend so much time to get it right and perfect! But it's fun, and if it can help others the better.

    Best regards,
    Thierry

    Quote Originally Posted by Pham Minh Son View Post
    Thierry, if I have a company myself you would be the top priority on my list to hire; your professionalism is much appreciated not only myself but all the folks who decided to go with Sinar system.

    Best Regards,
    -Son

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    Re: AFD MTFs?

    Bradley -- when I was testing the Leaf AFI and Sinar Hy6, I compared my 80mm f/2.8 Tele-Xenar AF to the AFD version, and the results were absolutely identical at all apertures I tested (2.8, 5.6, 8, and 11). The only difference is that they left out the aperture ring, which I think was a very bad decision. For my money, I would prefer just to have the previous AF versions, rather than the AFD...why pay more for less? If there is any difference other than the lack of an aperture ring, I would be curious to hear it.

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    Re: AFD MTFs?

    Hi, guys,

    Thank you for the replies.

    Son, you are correct, this thread is a request for the AFD MTF's not the (AF MTF's).

    Sinar has informed me that manufacturing tolerances have improved to the point where AFD lenses are guaranteed to deliver 60lp/mm (location unspecified) as opposed to 40lp/mm of the previous generation AF versions.

    This is a minimum figure--typically these lenses would resolve much higher than this, so there may indeed be no practical difference in image quality. On the other hand, if the new tolerances do deliver markedly improved resolution, I would expect to be able to see a difference in the MTF curves.

    So for now, I think I will look at the AF lenses rather than the AFD's (AFD's are 30-50% more expensive), but if someone does come across an AFD MTF, I would love to see it.

    Thanks everyone, much appreciated.
    -Brad

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    Re: AFD MTFs?

    Hey Brad,

    Thanks for the information about Sinar's statement. If they indeed improve the tolerances, that is a good thing. That said, original AF lenses should be the same performance given that they are in spec. You might be better served by just testing a few AF lenses and seeing how they compare. I may just have gotten lucky, but comparing the AFD and the AF on 33mp backs, the results were identical. I don't know how many lp/mm that is, but it is a pretty good amount. Anyway, while I believe that they have made tolerances tighter, I am not so sure they weren't tight to begin with. And I know I said it already, but getting rid of the aperture ring and then charging more really gets me hot under the collar! The aperture ring allows you to see exactly what setting the lens is on all the time, and it makes it very quick and sure to place the lens on P or T priority. The trend of making cameras less and less tactile is really a bad one in my opinion, and just because you CAN set the aperture on the camera doesn't mean that you should have to. Sorry to harp on that, it is just one of my big pet peeves.

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    Senior Member Graham Mitchell's Avatar
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    Re: AFD MTFs?

    Quote Originally Posted by Stuart Richardson View Post
    and just because you CAN set the aperture on the camera doesn't mean that you should have to. Sorry to harp on that, it is just one of my big pet peeves.
    I can see the thinking behind it - you can't have both, or there would need to be a way for the aperture ring to move automatically when the camera is set, and that would be a bad design.

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    Re: AFD MTFs?

    Quote Originally Posted by Stuart Richardson View Post
    Hey Brad,

    ... comparing the AFD and the AF on 33mp backs, the results were identical. I don't know how many lp/mm that is, but it is a pretty good amount...
    Hi Stuart,

    Are you making a subjective judgement here, or did you actually measure this? I ask this because the amount of detail necessary to distinguish the performance of a 40 lp/mm lens from a 60 lp/mm lens is quite small.

    A lens with resolving power of 40 lp/mm can theoretically distinguish a feature no smaller than 0.0125mm, and a lens with resolving power of 60 lp/mm can theoretically distinguish a feature no smaller than 0.0083mm.

    So, to see a difference between two such lenses, you would have to be able test them with object features smaller than 0.0125mm but greater than 0.0083mm. Otherwise, if none of the image details were in this range, both lenses would appear to be identical.

    I am curious about the setup you used to actually distinguish these fine details in this range. Can you elaborate on how you did this? Thanks!

    If it is only a subjective judgement, the odds are that you did not have these range of fine details in your images.

    David

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    Re: AFD MTFs?

    Stuart, David, you have hit on exactly the problem I have with the lp/mm statement.

    We're being told the minimum performance guarantee. I suspect the "guarantee" holds true over the entire image circle, but to be clear that is my supposition--Sinar did not specify what region the lp/mm figure was for.

    That being said, if the typical lens resolves over 100lp/mm over most of its image circle (which would not be unreasonable for glass of this caliber), then a 50% improvement in the minimum might not be noticable--and indeed this is what Stuart is reporting.

    On the other hand, if the typical lens struggles to get much above the lp/mm guarantee, then the AFD lenses could represent as much as a 50% improvement in resolving power.

    In practice, I am aware that the former case is usually the norm. In fact, Zeiss (Kornelius Fleischer) reported 250lp/mm resolving power back in 2001:

    I get 250 lp/mm with the Zeiss Distagon on Agfaortho 25. It took me some years to develop the technique and eliminate all influence factors that usually prevent a tester from getting resolutions that high. By the way, I am not the only one who has mastered this technique. There are more Hasselblad users out there who reach 200 lp/mm and beyond.

    I believe that Schneider glass should be comparable in capability.

    That brings me to Stuart's suggestion of testing. Unfortunately testing these lenses is both difficult (none in my area) and potentially fruitless, since the digital back I have today (eMo 75LV) has a theoretical maximum resolution of 69lp/mm... Even the oldest glass should still be able to outresolve my sensor--so I need to move to 6x6 film, get a 6060 film back for the Hy6 (whoops, not available), and get my hands on a good Imacon FlexTight scanner, etc... There is also the time committment as well. Do the results hold true for the AFD lineup in general? Am I testing a good copy? A bad copy? You can see where this is going!

    Instead, I look at it this way: basically any significant increase in resolving power will show up in an MTF chart, provided the charts are created from measurements of real-world lenses (and I believe the Zeiss and Rollei charts are some of the few that do this). It doesn't really matter to me how they do it--by better manufacturing tolerances, new optical formulae, or with "lasers" , improved resolution is something the MTF is designed to reveal--it should show up in the results. The Sinar & F&H guys know what they're doing--I have more confidence in their ability to measure performance than I do in mine. Plus, I'd rather be...(insert beer/wine/biking/eating/dancing/mountaineering/and oh yeah, making art!)

    Stuart, your experience agrees with others I have spoken with in that no one seems to be able to tell the difference (at least on today's backs). Based on that, until I can get a good look at an AFD MTF, I think going with the standard AF lenses for the time being is the most pragmatic approach.

    As for the aperture ring, I don't think I'm as bothered about the loss of the as you might be, partly because I suspect I'll be leaving the ring on 'A' all the time anyway (the handle grip has controls for both the shutter speed and aperture.

    I had thought you were going to say the tactile feel of moving the ring was the bigger issue. I'm a bit puzzled because given that we're usually looking through the viewfinder when we take pictures, why look away to check the ring--the camera shows what aperture it's set to right in the finder. But I can understand everyone has their preferences, of course. I just ask in case I'm missing something obvious...

    Son, thank you for the writeup on the MF lenses. As you know, I now have several MF lenses and love the way they handle. But because I will also be using these in the field, I may not always have two hands available--I may be in the mountains, or in a tree scouting my quarry. It will be nice to have AF at least for those lenses that offer it--I can (and will) still use MF in many situations. I was also unaware of the difference in MTF between the MF 180/2.8 and the AF 180/2.8. Thank you!

    Kind regards,
    Brad
    Last edited by BradleyGibson; 9th June 2008 at 17:00.

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    Senior Member EH21's Avatar
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    Re: AFD MTFs?

    I think Brad's right, and if so then the lenses are going to out-resolve the sensors anyhow. Just roughly calculating here....If you're getting 100 lp/mm then you've got one line pair for every 10 microns or about 1 sensor well. But a sensor well isn't going to see a line pair, but only a line so won't be able to resolve this. I think this is still true with the p45 or e75 as their well to well spacing is what 7 microns?

    This is probably why Stuart you didn't see a difference, between the AFD and older 80mm lenses and why nearly all of my 12 rollei lenses appear to have approximately the same sharpness (well okay 11, shouldn't count the imagon in this one). Just seen what the sensor can do. But I guess if we eventually have smaller well sizes in future sensors it will be important.

    Having said all that, there are notable differences in Macro contrast and color and bokeh between the different lenses.

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    Re: AFD MTFs?

    re:aperture ring

    I like this - It's nice for example to know you can just count three clicks on either adjustment and get one stop. Say you look at the histogram and decide its underexposed - you can just count three clicks on the aperture (Rollei 6008 does 1/3 stop adjustments) or shutter and know you made the adjustment. You don't have to look - you know it.

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    Re: AFD MTFs?

    David -- the setup was not scientific, so I don't want to give the impression that my testing is definitive and rigorous. It was done at Calumet in New York. It was a setup with a color chart, various finely textured items and so on. It was lit by strobes, obviously with a tripod. I tested both AF and manual focus. I could not see any difference between the lenses on either the AFI or the Emotion 75...I am not saying there isn't a difference, just that I can't see it.

    As for the ring, I am sure some people won't care. Brad the tactile feel of the ring is the most important thing to me. I just like setting with a ring on the lens rather than with a wheel on the body. I am used to Leica M, Leica R, Canon FD, Hasselblad, 4x5 and so on. Old habits die hard.

    That said, I find the ability to look at the setting on the lens very helpful on the 6008AF because I use the waist-level finder. I am looking down that way anyway. The other thing is that the 6008AF turns off every 30 seconds or so to save battery life, so it takes a second to turn back on when you are using it. Having the aperture there immediately visibly confirmable makes it easier to just turn it on and fire. This is probably not an issue on the Hy6.

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    Re: AFD MTFs?

    Well, this now begs the question as to why Sinar (and Leaf) decided to build these new AFD lenses. If the higher lp/mm tolerances cannot realistically be seen, and the manual aperture rings are preferred (or at best, do not matter to most), then what seems to be the point of the new AFD lenses?

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    Re: AFD MTFs?

    I'm with Stuart (and others) in preferring the aperture ring, albeit for a different reason. On more than one occasion I have inadvertently changed the aperture with the dial below the shutter release button. And yes, I do know that you can program the soft key to lock this. Also, I'll underscore Son's comment above about the quality of the Rollei lenses. Typically when getting into a new system I buy more lenses than I intend to keep and then decide which to sell. I recently tested the 80, 90 and 110mm lenses and they are all so good that I simply can't make that decision based on image quality. Other things, yes, but image quality, nope.
    Last edited by David K; 9th June 2008 at 22:18.

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    Re: AFD MTFs?

    Well, not to be cynical, but probably to take advantage of the digital marketing revolution and sell new lenses. There are a lot of used lenses out there for the 6000 series, and it would be easier for Sinar and Leaf to change them a bit and "optimize" them for digital, leading most people to just buy them out of a perceived sense that the older lenses are inferior. Most people coming to the system who don't know about it might assume that since most of the designs are older and made for film, that they are somehow inadequate for digital. They were superb to begin with and they are surely still superb on digital. But the fact remains that they are a business and if they go out and ask someone to pay over 30,000 dollars for a camera, back and lens, it is an easier sell if every part of that kit is "new and optimized for digital", rather than, "here's your 30,000 camera and standard lens based on the Xenotar from a 50 year old Rollei TLR".

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    Re: AFD MTFs?

    I have a quick question too, perhaps someone can answer it. Another disadvantage I can see of not having an aperture ring would be that the lenses might not be fully compatible with the older cameras. Does anyone know the story on this? I imagine that it would still work in program or shutter priority mode on a 6008, but not in aperture priority or manual mode. If it does work in those modes, how does one set the aperture?

    This would be a disadvantage for anyone who has a Hy6 but also an older 6000 series body. It would mean that they couldn't really use a 6000 series camera for backup if all they had were AFD lenses...they would need to buy another Hy6 for backup if that was a concern to them....that's a hefty price for a backup.

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    Re: AFD MTFs?

    Looking at my Rollei lens collection I think some of these are a good 10-15 years old maybe more and still beautiful. I don't doubt that the newer ones will last as long so probably 15years from now there will be some crazy digital sensor that can take advantage of the quality. By then you'll be using your Hy6 as a backup for the Hy7 or whatever anyway. Probably not a bad investment if you plan to be in the game that long. Man I'd hate to see what the dollar to euro exchange rate will be then.

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    Re: AFD MTFs?

    I just got my 110/2 Zeiss from the US in MINT condition.
    I don't think a new one would be any different.
    In the box was a Lens booklet with the MTF info of all the Rollei lenses.
    If there is any interest I can scan each page.
    Regards,
    Willem.

    N.B The MTF's I have are only for the NON AFD Rollei lenses!

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    Re: AFD MTFs?

    Quote Originally Posted by Rethmeier View Post
    I just got my 110/2 Zeiss from the US in MINT condition.
    I don't think a new one would be any different.
    In the box was a Lens booklet with the MTF info of all the Rollei lenses.
    If there is any interest I can scan each page.
    Regards,
    Willem.

    N.B The MTF's I have are only for the NON AFD Rollei lenses!
    Glad to hear the lens was as represented. Always nice when that happens.

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    Re: AFD MTFs?


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    Re: AFD MTFs?

    Quote Originally Posted by Stuart Richardson View Post
    Well, not to be cynical, but probably to take advantage of the digital marketing revolution and sell new lenses. There are a lot of used lenses out there for the 6000 series, and it would be easier for Sinar and Leaf to change them a bit and "optimize" them for digital, leading most people to just buy them out of a perceived sense that the older lenses are inferior. Most people coming to the system who don't know about it might assume that since most of the designs are older and made for film, that they are somehow inadequate for digital. They were superb to begin with and they are surely still superb on digital. But the fact remains that they are a business and if they go out and ask someone to pay over 30,000 dollars for a camera, back and lens, it is an easier sell if every part of that kit is "new and optimized for digital", rather than, "here's your 30,000 camera and standard lens based on the Xenotar from a 50 year old Rollei TLR".
    So, if I understand you correctly, you think photographers are being baited with its new AFD lenses, without offering any real added value. Bradley also finds that there is no added value in the AFD lenses as well. For me, it is hard to believe that any business would invest in the "better fool" theory, especially Sinar.

    Maybe we should hear from Thierry on this issue.

    Thierry, please help us to understand what the value proposition is for these AFD lenses. Why should we be buying them? Thanks.

  28. #28
    thsinar
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    Re: AFD MTFs?

    Dear David,

    I have planed to inform on this subject. I did not yet, because I first want to have all the information and data from our people to give as correct an answer as possible.

    Thanks and best regards,
    Thierry

    Quote Originally Posted by David Klepacki View Post
    So, if I understand you correctly, you think photographers are being baited with its new AFD lenses, without offering any real added value. Bradley also finds that there is no added value in the AFD lenses as well. For me, it is hard to believe that any business would invest in the "better fool" theory, especially Sinar.

    Maybe we should hear from Thierry on this issue.

    Thierry, please help us to understand what the value proposition is for these AFD lenses. Why should we be buying them? Thanks.

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    Re: AFD MTFs?

    Those are not my words David. I don't think Sinar is trying to cheat anyone or saying they have done things that they haven't. I am looking at it as if they were a car company. Auto manufacturers often offer more or less the same car over the course of several model years. So while all they may have changed from 2007 to 2008 might be the shape of the taillights, they can still claim it is a new car.

    I think the Rollei/Sinar/Leaf group are doing the same thing -- taking the existing Rollei lenses and changing the cosmetics and incrementally improving the manufacturing process, but I don't think the "driver" is going to notice a difference because everything under the hood is the same. If the optical designs were at all different (I have been told they are not, but I would be happy to be proved wrong), then it might be a different story.

    Edit: I am interested to hear Thierry's remarks on the matter, because he is always a source of excellent information.
    Last edited by Stuart Richardson; 10th June 2008 at 08:12.

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    Re: AFD MTFs?

    Quote Originally Posted by Stuart Richardson View Post
    Those are not my words David. I don't think Sinar is trying to cheat anyone or saying they have done things that they haven't. I am looking at it as if they were a car company. Auto manufacturers often offer more or less the same car over the course of several model years. So while all they may have changed from 2007 to 2008 might be the shape of the taillights, they can still claim it is a new car.

    I think the Rollei/Sinar/Leaf group are doing the same thing -- taking the existing Rollei lenses and changing the cosmetics and incrementally improving the manufacturing process, but I don't think the "driver" is going to notice a difference because everything under the hood is the same. If the optical designs were at all different (I have been told they are not, but I would be happy to be proved wrong), then it might be a different story.

    Edit: I am interested to hear Thierry's remarks on the matter, because he is always a source of excellent information.
    Stuart, I did not mean to mis-state your remarks. I am only trying to clarify the significance of the AFD lenses, for everyone's benefits.

    The facts are that Bradley was already told by Sinar that the AFD lenses have improved resolution, but that there is actually no evidence of it, as you have discovered in your tests at Calumet. According to your car analogy, it would be like a car manufacturer who advertised that their latest model improved the gas mileage form 40 mpg to 60 mpg, and then later discovering that their new car did not really provide 60 mpg after all. It is not like a new yearly car model with cosmetic differences only. We are dealing here with a claim of markedly improved performance, without supporting evidence, especially from the customers (like yourself).

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    Re: AFD MTFs?

    Quote Originally Posted by thsinar View Post
    Dear David,

    I have planed to inform on this subject. I did not yet, because I first want to have all the information and data from our people to give as correct an answer as possible.

    Thanks and best regards,
    Thierry

    Thanks, Thierry.

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    Re: AFD MTFs?

    I don't doubt that the newer lenses are better than the old. The question is more whether we can benefit from them without newer sensor technology?

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    Re: AFD MTFs?

    I think you are missing a key semantic detail. Brad was told that the TOLERANCES were improved, not the actual lp/mm. So they will now toss back a lens that is between 40 and 59 lp/mm, whereas before they would toss it back if it was below 40. So you have a higher rate of quality control, but that does not mean the average lens out of the factory is any better, just that the worst ones out of the factory are better. I have a feeling that most of the rollei lenses more than met the tolerances.

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    Re: AFD MTFs?

    Quote Originally Posted by Stuart Richardson View Post
    ...I have a feeling that most of the rollei lenses more than met the tolerances.
    Exactly, and this feeling of yours is probably based on plenty of good experience. And, as someone already pointed out, the Rollei lenses are built to last a lifetime. So, the question still remains as to why Sinar decided on the need to produce these AFD lenses in the first place. I just don't think it is the "new car" business model that you propose. Rollei is still making their non-AFD lenses for its customers, who seem very satisfied.

    So far, no one has come forth, on any forum, to show the added value of the Sinar AFD lenses over the Rollei non-AFD versions. In fact, just the opposite has occurred. Not only your posts, but those from Son, DavidK, fotoz, and others are quite happy with and prefer the non-AFD versions of these lenses.

    So, whomever Sinar was targeting as their market for AFD lenses has yet to be heard. None of the experienced photographers like yourself seem to be adopting them, basically because the value proposition just doesn't seem to be there.

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    Re: AFD MTFs?

    There's a difference between "not finding added value" and "not having the information to know whether there is added value". I am definitely in the latter category, not the former.

    I'm content to wait until Thierry can report back if there is any more information to be had. I am in no rush. When I mentioned earlier that I would go with AF for now, I meant that if I did have to make a decision on an AF vs. an AFD tomorrow without any additional information, at a 30-50% price premium new, I would probably go for the AF--that is not to say I feel the AFD's have no added value, just that I don't have enough information to justify the additional cost.

    Hope that clarifies,
    Brad

    Quote Originally Posted by David Klepacki View Post
    So, if I understand you correctly, you think photographers are being baited with its new AFD lenses, without offering any real added value. Bradley also finds that there is no added value in the AFD lenses as well. For me, it is hard to believe that any business would invest in the "better fool" theory, especially Sinar.

    Maybe we should hear from Thierry on this issue.

    Thierry, please help us to understand what the value proposition is for these AFD lenses. Why should we be buying them? Thanks.

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    Re: AFD MTFs?

    Quote Originally Posted by Stuart Richardson View Post
    I think you are missing a key semantic detail. Brad was told that the TOLERANCES were improved, not the actual lp/mm. So they will now toss back a lens that is between 40 and 59 lp/mm, whereas before they would toss it back if it was below 40. So you have a higher rate of quality control, but that does not mean the average lens out of the factory is any better, just that the worst ones out of the factory are better. I have a feeling that most of the rollei lenses more than met the tolerances.
    Yes, Stuart--this is the point I was clumsily trying to make-you state it very clearly here, thank you!

    Based on this, the new lenses on average *might* be significantly better, or they might not. There is not enough information to tell.

    -Brad

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    Re: AFD MTFs?

    Quote Originally Posted by BradleyGibson View Post
    Yes, Stuart--this is the point I was clumsily trying to make-you state it very clearly here, thank you!

    Based on this, the new lenses on average *might* be significantly better, or they might not. There is not enough information to tell.

    -Brad
    Yes, I think we all agree on this. We will just have to wait to hear the actual value proposition from Thierry regarding Sinar's new AFD lenses, and why they felt it necessary to introduce new lenses that may or may not be improvements over the non-AFD versions.

  38. #38
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    Re: AFD MTFs?

    Alright, here I am with some details about the Hy6 new AFD lenses and the difference(s) with the older AF and non-AF lenses for the Rolleiflex 6008:

    - first of all yes, there are tighter tolerances set for the new AFD lenses, to be sure to match the digital resolution requirements. This does not mean that a AFD does necessarily outperform older existing AF and non-AF lenses used on the Hy6, but that it could happen that one particular sample of an older lens gives inferior results.

    But the MAIN differences between those new AFD and the previous AF and non-AF lenses are:

    - AFD lenses take in count the focus difference (longer path) due to the IR filter on top of the sensor. The glasses, though not newly designed, have been adapted for this.

    - The electronic of these AFD lenses is built in a way that the lens can be controlled correctly by the Hy6 camera. This is not always the case with older AF lenses, depending when the lens has been purchased. However, if this AF lens cannot be used in AF mode, it is always possible to use it manually on the Hy6. Or then this older AF lens can be sent to Franke & Heidecke (or their distributors) to undergo a modification of the electronic in order to enable a correct control and AF.

    This is all I can say for the time being. Sinar does in no way force people to buy new AFD lenses, nor do we say that the quality will be much better. One of the advantages of the Hy6 system is that it can take totally more than 45 different and existing (still available or discontinued) lenses (see table attached, and which I did already post in an earlier thread here and elsewhere).

    Best regards,
    Thierry

    Quote Originally Posted by David Klepacki View Post
    Yes, I think we all agree on this. We will just have to wait to hear the actual value proposition from Thierry regarding Sinar's new AFD lenses, and why they felt it necessary to introduce new lenses that may or may not be improvements over the non-AFD versions.

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    Re: AFD MTFs?

    Thanks for following up on this Thierry.

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    Re: AFD MTFs?

    Thierry, thank you for the information. It's great to have such support.

    I appreciate this approach to lenses where folks are not forced to upgrade to the latest and greatest, and yet have the option to do so.

    Much appreciated,
    -Brad

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    Re: AFD MTFs?

    Thanks for the information Thierry. This clears things up nicely. Now people can make an informed decision about whether they want to embrace the new lenses or make do with the old.

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    Re: AFD MTFs?

    Quote Originally Posted by thsinar View Post
    ...
    - AFD lenses take in count the focus difference (longer path) due to the IR filter on top of the sensor. The glasses, though not newly designed, have been adapted for this.
    ...

    Thanks Thierry. As always, excellent information.

    Can you tell us how this particular difference affects the actual image quality? Does it affect resolution, contrast or CA (or all three?) of the image at the sensor? It would be interesting to know why this had to be done in the optics, as opposed to compensation via the focusing electronics.

    Thanks again,

    David

  43. #43
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    Re: AFD MTFs?

    I don't think that this correction has any influence on IQ (negative or positive) other than making sure that the focus is exactly in the sensor plane.

    Why doing it in the optic itself is a good question: I believe that it is not an optical modification but a mechanical in the lens as well as in the AF system in it.

    Thierry

    Quote Originally Posted by David Klepacki View Post
    Thanks Thierry. As always, excellent information.

    Can you tell us how this particular difference affects the actual image quality? Does it affect resolution, contrast or CA (or all three?) of the image at the sensor? It would be interesting to know why this had to be done in the optics, as opposed to compensation via the focusing electronics.

    Thanks again,

    David

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    Re: AFD MTFs?

    Thanks Thierry.

    So, if I understand correctly, the Hy6 is able to tell whether there is a film back or a digital back attached, and is able to dynamically adjust the lens for more accurate focus in either case.

    Whereas, the older non-AFD lenses would not be able to be adjusted by the Hy6 to compensate for the IR plate of the digital back, since those lenses were designed when only film backs were in use. Is this correct?

    David

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    Re: AFD MTFs?

    If David is right, (what he says seems reasonable) I would hope that there would be some sort of manual adjustment so you can set the camera for a digital back or film. I'm thinking of getting an Hy6. I will rarely if ever use it with film. I don't want my two manual 6008 lenses to be at a focusing disadvantage.

    But, I'm confused. If you were to focus an AFD lens manually, I would think it would be subject to the same focusing error as pre-AFD lenses, i.e. that the distance to the viewing screen from the mirror, while the same as to the film plane, is different than the distance from the sensor to the mirror. So there would have to be an auto adjustment made when you pressed the shutter button or you couldn't manually focus accurately.

    I plan on using all manual lenses if I get a Hy6. I hope (and think) I'm not understanding this, but it would be good to hear the facts. But, Theirry is probably asleep now.

    Best,

    Mitchell

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    Re: AFD MTFs?

    Mitchell,

    According to the information above from Thierry, only the AFD lenses are able to compensate for the IR glass in front of the sensor. If this compensation could have been done in the camera or back, there would not be any need to modify the lens.

    However, I am not sure exactly what happens when you switch to a film back while still using an AFD lens. In this case, I would think the camera or back must somehow "ignore" the additional compensation that was introduced by the AFD lens for the digital sensor. Or, maybe the AFD lenses are really not recommended for use with film backs. I guess we need more information here.

    David

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    Re: AFD MTFs?

    I am guessing that manual focus will be unchanged, given that this camera has been setup with a normal viewfinder and that there are several manual focus lenses still sold with the camera. I doubt this compensation will make much of a difference for film. Digital sensors are perfectly flat and make extremely high demands on the plane of focus being absolutely spot on. Film has a natural curvature and depth to the emulsion that makes these focal issues not quite as critical. I would assume that Sinar, Rolleiflex and Leaf are wise enough not to ship a camera that can shoot film, but does not correctly focus with it. I think this is one of the cases where it is angels dancing on the head of a pin...that 1mm or less difference in focal plane will not likely make a difference unless you are looking at 100% pixels on a 33mp or above back.

  48. #48
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    Re: AFD MTFs?

    That's what I think as well. I believe the issue has been thought through to the last detail. With the exception that some older AF and non-AF are not communication properly with the Hy6 (and which can be sent for an update), there should be no issue.

    Best regards,
    Thierry

    Quote Originally Posted by Stuart Richardson View Post
    I am guessing that manual focus will be unchanged, given that this camera has been setup with a normal viewfinder and that there are several manual focus lenses still sold with the camera. I doubt this compensation will make much of a difference for film. Digital sensors are perfectly flat and make extremely high demands on the plane of focus being absolutely spot on. Film has a natural curvature and depth to the emulsion that makes these focal issues not quite as critical. I would assume that Sinar, Rolleiflex and Leaf are wise enough not to ship a camera that can shoot film, but does not correctly focus with it. I think this is one of the cases where it is angels dancing on the head of a pin...that 1mm or less difference in focal plane will not likely make a difference unless you are looking at 100% pixels on a 33mp or above back.

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    Re: AFD MTFs?

    OK, got it.

    So, what this all adds up to is that if you want the highest degree of focusing accuracy for use with a digital sensor (like the eMotion 75), the AFD lenses will have an edge over the non-AFD lenses, since the AFD lenses have been specifically modified to take these digital sensors into account.

    I think this explains why Sinar made these newer AFD lenses, so that every last bit of focusing precision could be extracted from their latest digital sensors with the Hy6. Apparently, there was room for improvement over the older non-AFD lenses in this regard.

    Thanks!

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    Re: AFD MTFs?

    I'm afraid I'm still a little lost.

    Given that one can focus at any distance within the range of a manual lens, it seems very unfortunate if only AFD lenses can focus with complete accuracy with a digital back because of some auto compensating mechanism. If we are just talking about the depth of the IR filter, there should be a way to compensate for that. It sounds as if with non-AFD lenses, you can focus with greater accuracy with film than with digital, just the opposite from what I would choose.

    I think for the price of the camera, manual lenses with focus compensation should focus as well as AFD.

    I know this is all speculation, and suspect I'm not understanding, but I'd like an explanation.

    Best,

    Mitchell

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