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Thread: Tilt and your tech cam - how often with short lenses?

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    Tilt and your tech cam - how often with short lenses?

    How often do you use tilt with short lenses? Or: Would you miss something if you could only tilt with lenses longer than 80mm? (I'm about to enter Dante's world, main subject is interior design in museums and architecture. Still trying to do my homework ...)

    Jack's review of the Cambo with the 40mm Rodenstock (http://forum.getdpi.com/forum/showthread.php?t=13238) shows how useful tilt/swing can be. I am wondering wether the lack of tilt with WA lenses in the Alpa family might turn out a problem.

    Thanks for you comments!

    Chris

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    Re: Tilt and your tech cam - how often with short lenses?

    I am new and learning to using tilt. That being said, I am definitely using tilt with my 35mm lens on a regular basis (I'm using the Arca Rm3D). I was looking at Alpa gear last week and the fact that tilt only starts at 80mm with the short barrel lenses is a bummer. I'm not expert enough at using tilt or using Alpa gear to give advice but what I can say is that it is very simple on the Arca and you need no additional gear (adapters).

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    Re: Tilt and your tech cam - how often with short lenses?

    My own experience with tilt seems to be primarily associated with short lenses both for landscape and architecture and with longer lenses for product photography.
    I would find an 80mm restriction far too long to be useful for most of what I shoot with my P65+.
    -bob

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    Re: Tilt and your tech cam - how often with short lenses?

    As an Alpa user I have to say that the lack of tilt capabilities with wide angle glass is inconvenient for landscape work. If I had it, I'd definitely use it. Instead when I need more DoF I have to resort to stopping down further than I'd like than f/8-f/11 and/or focus stacking & using Helicon Focus - both of which are a pain & extra steps for an image. (Although the same applies to shooting with DSLR too)
    Last edited by GrahamWelland; 15th February 2011 at 08:08.

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    Re: Tilt and your tech cam - how often with short lenses?


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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by cly View Post
    How often do you use tilt with short lenses? Or: Would you miss something if you could only tilt with lenses longer than 80mm? (I'm about to enter Dante's world, main subject is interior design in museums and architecture. Still trying to do my homework ...)

    Jack's review of the Cambo with the 40mm Rodenstock (http://forum.getdpi.com/forum/showthread.php?t=13238) shows how useful tilt/swing can be. I am wondering wether the lack of tilt with WA lenses in the Alpa family might turn out a problem.

    Thanks for you comments!

    Chris
    Chris,

    Bob's rule of thumb with WA and longer lenses usage is spot on.

    I have both my HR28/35 lenses with no T/S mount. But my HR40 is T/S mounted.

    Prior to HR40, I would us my HR28 permanently on the WRS and a lot of my shots were at infinity @ f8. Yes, I wish I had a 1* tilt to get a bit more DOF.

    I now use my HR40 more because of the movements. I look forward to mount my HR28 on T/S as well - but the amount of T/S for the HR28 would be very minimal to justify the cost at this stage - that's based on the minimal amount of movement with my HR40 ie rarely do I go beyond 1-2* @ f8 infinity. Although the IC of the HR40 is 90mm and HR28 is only 70mm, the sensor that I am using would allow me at least 3* more with the HR28. I just have not met a situation that I could say: "gosh, I wish I could get 3* more of my DOF" - that's because I avoided that scenario.

    I love to be able to have my HR90 T/S mounted for close up but NOT able to do so at the moment by Cambo people. Only the Digitar 90mm is capable of doing so at the moment. Here lies the adv of Alpa HR90 short barrel mount w/ T/S adapter.

    However, do try out Sinar arTec as it allow all 4 movements on the camera and NOT on the lens mount (ie Cambo) - and where you are, you have better access to Sinar. You can then mount most std Sinar mount lenses from HR23 (landscapes) to HR90 and greater (products) onto the arTec and have movements . However, with the arTec, unfortunately, you cannot do both T/S together at the same time like that of Cambo T/S lens mount.

    Hope that helps....

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    Re: Tilt and your tech cam - how often with short lenses?

    going by the book, if your lens is 5' above the ground and you are focused at infinity:

    43mm lens would need 1.5 degree tilt (the same net fl as the 28 in the hasselblad HTS)
    70mm lens: 2.5 degrees

    this would produce a plane of focus of the level ground

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    Re: Tilt and your tech cam - how often with short lenses?

    With the Artec you can combine tilt and swing,by rotating the lens standard.But it's less convenient than with a tec camera with separate gears for tilt and swing like the Monolith ,because the lens standard of the Artec is not geared and has marks each 10 degrees.
    And yes, one degree forward tilt helps bringing the foreground in sharp focus(I use the 40mm Rodenstock).
    Pedro.

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by jlm View Post
    going by the book, if your lens is 5' above the ground and you are focused at infinity:

    43mm lens would need 1.5 degree tilt (the same net fl as the 28 in the hasselblad HTS)
    70mm lens: 2.5 degrees

    this would produce a plane of focus of the level ground
    The Scheimpflug Rule
    The gloriously named Scheimpflug Rule says that if the subject plane, the plane of the lens panel and the image plane all meet at a common line, everything in the subject plane will be in focus in the image plane.

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    Re: Tilt and your tech cam - how often with short lenses?

    Chris,

    I am carefully considering getting a tech camera, as such perhaps my thoughts can be of some value.

    It is my belief that it is important to focus on the image and what we wish as far as rendering. When looking at the two train car photos in http://forum.getdpi.com/forum/showthread.php?t=13238 I actually prefer the first where the near of train car is sharp and far is not, because it add a sense of depth. Likewise I find similar interesting in landscape images because it add depth. However, I am also someone who prefer to have light fall off in images... because it likewise creates focus. When I say this, do consider that the sensor/film size of a digital back is significant smaller than 4x5, for which tilts are very mandatory for landscapes.

    My prime interest is in Alpa since they arguably offer tighter tolerances than any other system made today, including possibility to shimming back, strict fabrication tolerances, roller bearings etc, and the fact that tilts are not built into the camera itself. With cameras having tilts built in it appears to me as one factor that need to be zeroed to perfection for each shot and which is difficult if not impossible to make to same tolerances one can shim an Alpa. Why? Lets remember Alpa can be shimmed to 0.01mm tolerance. That is extremely small. All is a trade off though, thus depends on our preferences and intended use. Thus, what do you prefer, tilts or the preciseness of an Alpa?

    A thought of something to complement an Alpa system with is for me a Shen-Hao 6x9 non folding camera to add movements for select situations. If that one would be fitted with a rear mount to enable mounting Alpa groundglass and back mount to tight tolerance this would add what is most critical in chain when needing accurate focus for tilts for select situations (the tolerance in plane between groundlass and sensor of digital back). Rodenstock makes a 6x loupe that covers a reasonably large viewing area and which can be used to focus.

    I hope above help or at least share some different considerations.

    Regards
    Anders

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    Re: Tilt and your tech cam - how often with short lenses?

    I would postulate that the precision and shimming of the alpa is only useful to ensure that if your lens is on the infinity stop, on the stop, not just the pointer on the mark, you are in focus.

    at any other focus distance, the imprecision of the lens distance markings, coupled with however you measure distance to subject, completely override any high tolerance shimming. and if you are using the gg, shimming is not a factor.

    the shimming i am referring to is only for distance to film plane, not parallelism

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by Anders_HK View Post
    Chris,

    My prime interest is in Alpa since they arguably offer tighter tolerances than any other system made today, including possibility to shimming back, strict fabrication tolerances, roller bearings etc, and the fact that tilts are not built into the camera itself. With cameras having tilts built in it appears to me as one factor that need to be zeroed to perfection for each shot and which is difficult if not impossible to make to same tolerances one can shim an Alpa. Why? Lets remember Alpa can be shimmed to 0.01mm tolerance. That is extremely small. All is a trade off though, thus depends on our preferences and intended use. Thus, what do you prefer, tilts or the preciseness of an Alpa?



    Regards
    Anders
    Why do you say that only Alpa has the possibility of shimming backs? Technically couldn't you shim the back with any system?

    On the Arca system you can calibrate focus.


    .
    Last edited by Terry; 27th February 2011 at 07:54.

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    Re: Tilt and your tech cam - how often with short lenses?

    i should also add that the alpa concept shimming of the back does not carry over for multiple lenses. Wouldn't it have made more sense to shim each lens?

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by jlm View Post
    i should also add that the alpa concept shimming of the back does not carry over for multiple lenses. Wouldn't it have made more sense to shim each lens?
    That's what you pay the extra Alpa tax on the lenses for. They are supposed to be accurately calibrated to the mount and the precision of the lens mount/body/spacer/back plate is supposed to be set and consistent. The only part not set up by Alpa is the digital back so hence the shunning per application. (That said, I'm sure as an engineer you could argue that there's tolerance at every step in the chain ... Etc etc )
    Remember: adventure before dementia!

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    Re: Tilt and your tech cam - how often with short lenses?

    Hmm ... It seems people have already "forgotten" the lessons learned from Joe Holmes:

    http://www.josephholmes.com/news-med...precision.html

    According to Joe, the lenses for ALPA cameras are just as prone to inaccuracy as for any other camera, as he found large variation in image quality from both their Rodenstock and Schneider digital wides.

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    Re: Tilt and your tech cam - how often with short lenses?

    that was a lot to wade through!

    written in 2009...I'm hoping the Schneider and Rodenstock lens quality is improved, as he implies, but it looks like you have to personally calibrate each lens to your body/back to guarantee infinity focus can be achieved.

    the lesson to take home is that a 16 micron shift (about 1/6 the thickness of a sheet of paper) in lens to sensor distance constitutes a change in subject distance from infinity to 200' (for a 35mm lens at 5.6, if i recalled it correctly). makes the superfine helical focus ring on the arca seems sensible

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by David Klepacki View Post
    Hmm ... It seems people have already "forgotten" the lessons learned from Joe Holmes:

    http://www.josephholmes.com/news-med...precision.html

    According to Joe, the lenses for ALPA cameras are just as prone to inaccuracy as for any other camera, as he found large variation in image quality from both their Rodenstock and Schneider digital wides.
    If that's directed at my post then I'd also say that it seems that people have already "forgotten" to read the whole post too.

    Manufacturing tolerances are a fact of life. Sure, the arca approach of dialing in a calibration offset per lens (once you've determined what it is of course) whenever you use that lens, and using a chart/guide to map their focus dial to real distances, should provide a correct focus for that lens/back combo. However, when the sun is rising rapidly, you're freezing your butt off, you're trying to make sure that the scene is composed just as you want it, its dark as well just for good measure, now tell me that you'll dial in the correct offset, look up the focal point mapping and shoot the shot every time? I'm just saying ...

    Btw, I have a great deal of respect for Joseph Holmes and his tests, however, I recall that both Rodenstock & SK recommend pretty much any of the lenses he tested to be shot optimally between f/8 & f/11 with MFDBs. Pretty much the only glass I personally expect to perform optimally at their maximum aperture or +1 are Leica RF lenses. (and I'm not wishing to start a Leica lens war either btw).
    Last edited by GrahamWelland; 27th February 2011 at 20:49. Reason: Added Rodenstock/SK suggested optimum apertures for high res digital.
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    Re: Tilt and your tech cam - how often with short lenses?

    Graham - I think that is a little overly dramatic about how you use the Arca. Most people only have a couple of lenses and any adjustment factor is really quite small and simple to remember. In addition with the wider lenses for landscape you are working with a pretty short range of the focus helical.

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    Re: Tilt and your tech cam - how often with short lenses?

    Graham, I was just pointing out Joe's analysis and that Alpa has no tighter tolerances or precision than any other quality camera maker (e.g., Sinar, Arca, Linhof). In fact, I was careful not to advocate any one camera vendor over another in my post, so am not sure why you want to compare against Arca now. However, since you bring it up, I do agree with Terry here, and also that the Arca can still be shot in the same manner as any Alpa, and so it is not limited to the procedure that you describe.

    Also, Rodenstock does recommend F5.6 as an optimum aperture for their 28mm and 35mm lenses that Joe discusses.

    David

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    Re: Tilt and your tech cam - how often with short lenses?

    Following is my go relating to a number of the above recent posts. Comments are much appreciated and will assist in my own evaluation of deciding to go ahead with tech camera.

    Quote Originally Posted by David Klepacki View Post
    Graham, I was just pointing out Joe's analysis and that Alpa has no tighter tolerances or precision than any other quality camera maker (e.g., Sinar, Arca, Linhof).
    I missed that part. Appreciate if you would please paste a quote, thanks.


    Quote Originally Posted by GrahamWelland View Post
    That's what you pay the extra Alpa tax on the lenses for. They are supposed to be accurately calibrated to the mount and the precision of the lens mount/body/spacer/back plate is supposed to be set and consistent. The only part not set up by Alpa is the digital back so hence the shunning per application. (That said, I'm sure as an engineer you could argue that there's tolerance at every step in the chain ... Etc etc )
    I am an engineer, dont hit me! . What Joseph Holmes mentioned of the various parts, camera body, lens etc contributing to the whole is correct for basically anything that is fabricated. Not only that, each camera body, lens assembly etc is assembled of various components that each are made to specified fabrication tolerances, in order for the summation of all tolerances to result in a total of the component (e.g. camera body) being itself within a specified tolerance. Certain expensive high tech machinery is capable to fabricate individual parts to within 0.01mm tolerance. My guess is that is what is used to fabricate an Alpa system, and perhaps also Arca and Cambo components? However, the individual tolerances indeed add up to a total whole that is likely adjusted in fabrication in various ways at different stages. In this regards my guess is that Alpa makes their system as whole to tighter quality control, thus tighter tolerances.

    For a tech camera, it is also absolute important that the lenses be mounted and adjusted for the lens plane to be perfect parallel to the sensor plane (or back mount), and within tolerance to the acceptable tolerance to achieve focus. However, as Joseph Holmes mentioned, a loaner back was off by 175 micron, which is 0.175mm and which is huge in comparison (you will see that from what I type below). I would guess that back was a rare one…

    Back to Alpa...


    Quote Originally Posted by jlm View Post
    I would postulate that the precision and shimming of the alpa is only useful to ensure that if your lens is on the infinity stop, on the stop, not just the pointer on the mark, you are in focus.

    at any other focus distance, the imprecision of the lens distance markings, coupled with however you measure distance to subject, completely override any high tolerance shimming. and if you are using the gg, shimming is not a factor.
    Unlikely. The very nature of a lens being calibrated is that the infinity marking is calibrated since that is the reference mark for calibration. Thus, then consider that the turn of helical focus is large compared to the focus travel of the helical. This is why I believe what you state is not correct since you would be in control of focus point thanks to the calibrated tolerances of the system.

    As example, per what I was told by Schneider the critical tolerance of camera systems with adjusted flange focal distance at infinity is 0.02mm. Thus the infinity index of the helical mount has to be adjusted individually to the effective focus length of each lens to get a sharp image on infinity, or if this is failed by 0.02mm one cannot get a sharp image (per Schneider). Thus, obvious the loaner back that Joseph Holmes mentioned that was off by 0.175mm had a big problem. I am not sure if backs are always made to within 0.02mm (perhaps they are not), but obvious the shimming of Alpas (or “fudge” factors applied to tables for Arcas) do bring to within that tolerance, provided of course... that the sensor is perfect parallel to that camera system (and if not Alpa is the only one that offer a system of corner shims to compensate…).

    As we see, we are fighting for very precise tolerances…

    Now, 0.02mm is indeed very, very small and the turn on helical focus will need to be larger, or simply it will be very difficult to adjust focus for an image at any other setting than the infinity lock (if… at all that has been perfect calibrated to within 0.02mm tolerance).

    For the Schneider 24mm lens (which may be an exception with unusual small focus travel), the total focus travel from 1.5m to infinity is only 0.3mm. That is already very small. Thus it is perhaps not a wonder that Joseph Holmes found problem with this lens when focused at wide open. While the lens is recommended for use within f/5.6~11, what that means is that the lens is capable of being sharp within that aperture range. However that does not necessarily mean that the helical focus is capable to at all times reliable focus at those apertures, because a helical focus too has tolerances. Perhaps with use of a groundglass on an Alpa the chance of precise focus would improve, if assuming that the tolerances between groundglass and sensor are smaller than between sensor and helical and measurement to focus point??? Notably for the 24mm Alpa seem to offer their own helical focus... perhaps it is designed to be more precise??????

    Alpa enable the user to shim a back using shim plates as small as 0.01mm in order to ensure that it be shimmed to their system which is already within the critical 0.02mm tolerance. This is per my understanding (if I am correct) what really sets Alpa apart, including of course that all components also ensure of the total system (less back adapter plate) of being perfect parallel to lens plane. Thus all parts in Alpa system comes per my understanding already calibrated to very exact tolerances from the factory and which ensures to within 0.02mm critical tolerance. However please feel free to fill me in or correct me if I am wrong. I am keen to know and understand more.

    Thus with any body or lens of the Alpa system it should be possible to focus to high (acceptable) accuracy within the critical 0.02mm tolerance using any shimmed back. Other fabricators such as Arca and Cambo as example do not provide their systems with such readily precise tolerances from the factory but while perhaps fabricate components to 0.01mm tolerance do not carry tolerances through to ensure the system being as exact as Alpa, or is my understanding incorrect??? Thus the lenses of those systems may need to be calibrated individually, or "fudge" factors may need to be applied such as for Arca, and which may or may not be different for different lenses (note). Correct? Indeed please feel free to shoot or correct me if I am wrong in what I write. This said, it is possible that the helical focus of Arca enables more exact adjustment of a focal point at wide open and with tape measure or laser, if a correctly calibrated “fudge” factor is applied to the scales, if that helical focus is fabricated to exact precise tolerances to match its turns…. For some applications perhaps that is desirable system and preferred means to work, albeit seem tad tedious. For landscapes I am uncertain if it is necessary with such system, Alpa's appear more simple to use to myself, yet we speak of perhaps preferences...

    Back to tilts; with the critical 0.02mm tolerance it is my understanding that tilts cause complication, or??? 0.02mm is a very exact tolerance within which for each shot not requiring tilt that the lens will need to be zeroed to such tolerance. Perhaps the IQ backs with live view and focus confirmation a’la C1 “green mask” will assist in making that adjustment to point that it will not be much of an issue anymore, who knows??? However, there must also be risk that the tilt/zero adjustments get thrown out of tolerance between each shoot, or? Now, with this why would I speak of a Shen-Hao as a complement to an Alpa? Because the Alpa groundglass adhere to the within critical tolerance of the Alpa system and thus focus using the groundglass should result in acceptably sharp images using a shimmed back, if a custom mount with perfect flatness to fit the Alpa groundglass/back adapter is custom made for the Shen-Hao. The adjustments would be tedious and used for certain circumstances, but utilizing an aperture to yield a large DOF than wide open there will be some margin, perhaps even with a larger than required DOF the adjustment of tilt and shift will not be much issue???

    Comments are very welcome and much appreciated.

    Regards
    Anders

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    Re: Tilt and your tech cam - how often with short lenses?

    here is the way I see it:

    at all distances less than infinity, you are using something to judge focus: either the ground glass, the distance scale or best of all, your tethered laptop, and something to set the lens to sensor distance, usually a helical focus thread. All of these methods will have tolerance errors far in excess of .02mm. If you are satisfied with the tethered laptop as a judge of focus, none of those error tolerances will matter.

    Infinity is another story. On the one hand, you can evaluate focus at infinity using the laptop, but if your helical threads and the infinity stop won't let the lens travel far enough, you simply won't get focus. This travel limit is what Alpa is adjusting by back shimming and no more, and they assume that there is sufficient uniformity between lenses that if one lens works, they all will

    not sure what you are meaning here, in reference to my quote:

    "Unlikely. The very nature of a lens being calibrated is that the infinity marking is calibrated since that is the reference mark for calibration. Thus, then consider that the turn of helical focus is large compared to the focus travel of the helical and that is why I believe what you stated is not correct."

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    Re: Tilt and your tech cam - how often with short lenses?

    I see parts of what you mean now. Certainly tethering will be most precise to determine if acceptable focus since it is same as will be the capture. All others include tolerances, however if they are suffice small (summed up) and within what is critical to achieve focus, then the image should be reliably and consistently sharp.

    What I meant in what you quoted of me was that I thus believe the distance markings may well be within acceptable tolerance, since focus travel are along a much finer scale than the distance markings. However I do not see why the shimming would be overridden or why when using gg that shimming is not a factor. The gg should adhere to the tight tolerances of the Alpa system, and specifically the shimming is bringing the digital back to within those tolerances of the Alpa system per my understanding.

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    Re: Tilt and your tech cam - how often with short lenses?

    Thanks a lot for all your replies to my original question and for your comments, very much appreciated!

    It seems to me that the topic is moving away from tilt and towards the merits or problems of two different focusing systems. So I thought, it's time to explain why I started this thread - as the issue of focus is what I am still thinking about now.

    When I posted my tilt questions, I made a stupid mistake (which was pointed out to me in a personal conversation): I was wondering if would miss the possibility of tilt with short lenses and I was thinking about the floor/ground. I didn't think about the simple fact that there is also a ceiling which I want to have in focus, and that there is something between floor and ceiling ... So I have come to the conclusion that I won't miss anything, in my particular situation.

    Camera-wise the background of my question was Alpa. I had tested a Cambo WRS which, in a way, was a pleasant surprise. It seems to me that it is a remarkable camera but: it is plagued by serious flare problems. To me this is a show-stopper. At the same time I had an Arca RM3d for a brief test. It's an interesting camera but I am not convinced. Yes, focusing using a disto and a small table with the helicoid settings simply works. But I'm pretty sure that I would never be able to memorize the tables of three different lenses, so I would have to look up the correct value. Moreover, I had the impression that, at least for my way of working, the camera isn't optimal: for example, why on earth is it impossible to check the spirit levels if the camera is mounted at eye-level? In a way, this is a trivial problem but to me it is extremely important. It's definitely a nice camera but I wouldn't call it well thought-out. Enter Alpa. I don't like their marketing speech (and they should hire someone for proof reading before talking about all these things at the top …), I don't like the way they write about Arca on their web site, I don't believe in what they say about precision when it comes to a sliding back. But: So far I am really impressed by the Max. And that's the reason why I asked about tilt with short lenses.

    I have no doubt that, from a theoretical point of view, the Arca focusing approach is superior to everything else I know of. But I am not convinced that I won't be able to get the type of images I want using an Alpa with one of the new focusing rings. Obviously, this is something I have to make sure before making a decision. But at the time being I am gravitating towards Alpa. It seems to me that, for what I want to do with a tech cam, the Max is a better thought-out and more flexible tool.

    Chris

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    Re: Tilt and your tech cam - how often with short lenses?

    Chris, You started this thread by referencing Jack's image using tilt /swing. If this kind of focus control is needed, then there is really no other way to achieve this without such movements.

    For landscape and architectural shots, I often rely on tilt. For product shots, I rely more on swing. It is all about how you wish to "lead the eye" into your image.

    Maybe you should first consider which lenses are more attractive to you. If you prefer the Schneider Digitars, these lenses need to be stopped down a little more for their optimum aperture (around F11). However, the Rodenstock HR lenses are diffraction limited designs and will give you highest contrast at wider apertures, but possibly at the cost of more distortion than the Schneider equivalent lens. If you prefer the Rodenstock HR wide lenses, then I would recommend a camera that offers some tilt/swing (Sinar, Cambo, Arca, etc.) in order to manipulate the plane of focus with the idea of using their wider optimum apertures (F5.6 - F8). A benefit of being able to shoot at wider apertures is not only for lower light situations, but also to allow lower ISO with faster shutter speeds for less noise and less possible "movement" in the image that may cause blur (e.g., foliage in light wind).

    If these things are not an issue for you, and you typically work at/near F11, then the Rodenstock lenses may not be as good a choice as their rendering will soften (although still very good) due to diffraction when stopped down that much. In this case, tilt/swing is less of a necessity in terms of being able to work at the optimum lens aperture, but it may be desirable for compositional purposes (as in the example from Jack).

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    Senior Member dchew's Avatar
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    Re: Tilt and your tech cam - how often with short lenses?

    I think jlm makes a great point here. I recently rented a Cambo, P40+ with 35, 55 and 90mm lenses basically to see if I liked the overall tech-camera approach, which I did very much.

    However, I had a very difficult time focusing, so I did the usual flat-wall test with focus brackets. I was 15 feet away from the wall, and everything finally came in focus when the lens was at infinity! This was the case with all three lenses.

    By my rough measurements the back was about 10 thousandths of an inch off, which is huge. Furthermore, since all three lenses exhibited the same phenomenon, the tolerances were off somewhere between the camera, back adapter, back and sensor, not the lens mount forward.

    There was just no way to get anything in focus at much beyond 30 feet. I'm not slamming Cambo in any way. This was a rental; who knows what it had been through.

    I think every tech camera including Cambo has some method to adjust from the camera to the back. In the case of Cambo you need to send it back for calibration, where they remove the small painted-in bolts and presumably add or subtract shims (but do I have to send them my back??). Alpa and Arca give the user the ability to do it. Alpa's solution can handle out-of-plane adjustments (but what if I rotate the back?). Arca's can handle tolerance issues from the lens mount forward.

    Dave

    Quote Originally Posted by jlm View Post
    ...Infinity is another story. On the one hand, you can evaluate focus at infinity using the laptop, but if your helical threads and the infinity stop won't let the lens travel far enough, you simply won't get focus. This travel limit is what Alpa is adjusting by back shimming and no more, and they assume that there is sufficient uniformity between lenses that if one lens works, they all will

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by dchew View Post
    Alpa and Arca give the user the ability to do it. Alpa's solution can handle out-of-plane adjustments (but what if I rotate the back?).
    Assuming the Alpa system do have the required tight tolerances, then it should work fine. That seems as the very key point with that system compared to the others. The shimming merely shims the back to near perfect to their system and which already should have the tolerances required. Thus their system should be within acceptable tolerances no matter if back is rotated. Question is then how Leaf's rotating sensors will work in relation to the very tight tolerances, but I gather one could shim such back for sensor in one position and hope/try to see how well it works also in the other.

    For Arca if a sensor is too much out of tolerance then there seems there is no way to adjust parallelism, only longitudinal focus per say. For Cambo there was a post in LuLa of custom shimming a Cambo RS http://www.luminous-landscape.com/fo...?topic=49977.0. However, assuming no shims are in there from factory it appers that one can only add shims, and which will need to be balanced by adjusting helical focus (three screws I believe on Schneider).

    Assuming Alpa is within the alleged tolerances, it appears to me as a more simple system for a user in order to achieve optimum sharpness in images. The downside of Alpa is that they do not inform clear what applies to their system as far as how tolerances and more work. Indeed in marketing they appear somewhat arrogant, and by email tend to many times not give fact replies to queries. Those comments do not apply to Optechsdigital who gives truly excellent, credible and brilliant clear tech replies.

    Regards
    Anders

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    Senior Member Steve Hendrix's Avatar
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    Re: Tilt and your tech cam - how often with short lenses?

    Chris -

    I agree, for interiors, use of tilt may have some drawbacks (ceilings, for example, as you referenced). That said, recently we had a group testing the Arca Swiss RL3D with the 43mm Digitar (and P65+). Without remembering all the exact specifics, what we found was that just adding a few degrees of tilt produced a significant range of focus from just a few feet in front of the camera to infinity. We did notice that focus of an overhanging ledge roughly 20 - 30 feet away, and about 15 - 20 feet in the air was also achieved. So, for landscape, we can certainly see an application for tilt, even on wide lenses.

    As far as where this thread has veered in terms of cameras and what they can do with focus and tolerances and precision, etc, etc. I would say that first off, when it comes to the sensor, it is certainly possible to have a digital back adjusted at the factory if the tolerances don't seem to be met. It's great that Alpa also offers a solution for adjusting the image plane of the digital back. On the other hand, this does also assume that all lenses are at the same tolerances. In this case, the Arca Swiss R series offers a precise and easy to use method for adjusting focus for any lens or any back with any lens, regardless of whether all are in harmonic convergence or not.

    I don't know that there is a right or wrong way, a better or worse way. I believe this is a very subjective topic. I also believe that there is a lot of misinformation about both products. In any case, one's preferences may come down to very individualistic terms about the cameras completely isolated from how they handle the lack of tolerances from any of the components.

    The last car purchase I made came down to several tilting (pun intended) factors - my choice had a straight on, line of sight key entry to the ignition, the open trunk button was in an easy to access location right at my left elbow, I liked the color of the inside lights at night, and I loved the steering wheel, the way my hands fit it. I think it drove accurately, but that was kind of a given. Even if it didn't, I felt I had ample tools to adjust. I see these products very similarly. Incidentally, any manufacturer claims of superior this or that mostly fell on my deaf ears. My advice is to never buy into that, instead prove them yourself and focus on the features that matter to you.


    Steve Hendrix
    Steve Hendrix, Sales Manager, www.captureintegration.com (e-mail Me)
    Digital Cam: Phase One | Leaf | Leica | Sinar Authorized Reseller
    TechCam: Alpa | Cambo | Arca Swiss | Sinar Authorized Reseller

  28. #28
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    Re: Tilt and your tech cam - how often with short lenses?

    I don't mean to get off the "tilt" subject but---
    I own a Cambo with the Schneider 47xl.
    I have not owned any other tech cams so I can't compare the quality with other cameras. I am a machinist by trade. I own an aviation machine shop and I think I know a little about precision.

    The Cambo in my opinion is a very well made and precision piece of equipment. It has an adjustment method that I think works better than shims. I don't think they want non technical people
    to fool with it. I adjusted my Cambo/P45 using the Alpa video instructions, only using the Cambo adjustment screw instead of shims. It worked great.

    I think they would do well to teach people to use their adjustments.
    They are taking an undeserved beating being quiet.

    Greg

  29. #29
    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by TEBnewyork View Post
    Graham - I think that is a little overly dramatic about how you use the Arca. Most people only have a couple of lenses and any adjustment factor is really quite small and simple to remember. In addition with the wider lenses for landscape you are working with a pretty short range of the focus helical.
    Terry,

    Yes, you're probably right. I'm just going by the procedure as I understand it and projecting on to the typical scenarios that I find myself in. I agree with John about the guaranteed precision of the Arca approach in so far as it factors in both back and lens corrections but I also know that at sunrise when I can hardly even see the settings on my camera, let alone look up tables for distances, that things get difficult. Heck, I have to walk around the front of my camera to see what the exposure is set to, look down from above to see what aperture and distance I've set and then finally fire off the shutter. For me, that's enough complexity and i confess that in many situations I'll take the easy path of using my favorite apertures, focus stacking against the marked distances and then letting the back tell me whether I need to change the exposure which I do by feel normally. These days I don't bother with the distometer but actually use my M9 to focus and then use the distance on the lens as my distance guide for the foreground. Doubtless not entirely accurate but since I find that I focus stack more often that not now it's good enough.


    Quote Originally Posted by Anders_HK View Post
    Assuming Alpa is within the alleged tolerances, it appears to me as a more simple system for a user in order to achieve optimum sharpness in images. The downside of Alpa is that they do not inform clear what applies to their system as far as how tolerances and more work. Indeed in marketing they appear somewhat arrogant, and by email tend to many times not give fact replies to queries. Those comments do not apply to Optechsdigital who gives truly excellent, credible and brilliant clear tech replies.

    Regards
    Anders
    Anders,

    I agree - I like my Alpa but they certainly do come over as contrite and arrogant on their site. I also agree with you about Paul & Ted at Optechs - very good folks to deal with and voices of reason even to Alpa's hype.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by David Klepacki View Post
    For landscape and architectural shots, I often rely on tilt. For product shots, I rely more on swing. It is all about how you wish to "lead the eye" into your image.
    David,

    I absolutely agree with you on this. Even with 35mm digital I was a regular user of T/S at 24/45/85mm and it's one thing that I wish Alpa had a better solution for. For still life & macro I'm sure that the T/S solution works well (I don't shoot them much generally, and not at all with the Alpa). What I do shoot regularly though is landscape and its here that the other tech systems such as the Arca & Cambo do seem to offer better solutions for wider glass. As I mentioned a while back, I miss this and would definitely use it if I had it. I'm sure that most landscape shooters of the Phase/Mamiya DSLR would do so also if they could too!
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by jlm View Post
    i should also add that the alpa concept shimming of the back does not carry over for multiple lenses. Wouldn't it have made more sense to shim each lens?
    Hi everyone, first post after a short while lurking (sounds so sordid!). Continuing the OT discussion on camera systems/tolerances etc, I came to the same conclusion as Jim while recently evaluating tech cameras for architectural work. i.e. Shimming works optimally only for the lens that you conducted the shimming process with.

    I've decided on the Cambo RS for anything needing movements, but have on my future wishlist an Alpa TC/SW with one lens. Both are beautiful systems IMO.

    The marketing hyperbole notwithstanding, I think all these camera systems are gorgeous and made well, but with individual quirks that give them their distinctive personalities.

    Stating the obvious: Every component in a system (lens, body, back) has a tolerance and these add up (average out?) when the components are assembled together. The big problems arise when something is out of tolerance, e.g. a dud lens or misaligned sensor.

    The quest for technical perfection is admirable but I would argue that it is non-attainable and self-defeating. An example: The marketing tells us and testing shows that shimming even 0.01mm provides noticeable improvement in performance. However, lenses are made to +/-0.02mm tolerance. Say you shim your body/back with a lens that is +0.02mm (within tolerance) but you have another lens in your kit that is -0.02mm (also within tolerance). That means when you mount your second lens you have effectively introduced a net 0.04mm intolerance into your system.

    I would argue that maybe we should accept that our gear is being made as good as possible given current technology and accept a certain "averaging" of errors/tolerances, apart from the manifestly dud lenses etc.

    I am not criticizing any particular camera system or philosophy, but what frustrates me is the black & white marketing that glosses over this reality of tolerances and compounding errors that will add up in any system.

    Actually, on second thought I WILL provide some constructive criticism to Cambo etc relating to comments made by others above: Alpa needs a good copywriter to remove from their website all the sarcastic comments regarding their competitors' products, plus maybe tone down the arrogance a bit. It's not professional and not attractive. Seems almost insecure. Cambo and Arca need to market themselves more aggressively, maybe even turn up the bling a little bit. Then again, it seems these companies are showing the face they want to show, doing things the way they want to do it, and are doing quite fine without me thank you very much.

    So ... I know that was a bit heavy for a first post, but I didn't want to start with the old favorite "what camera should I buy if I have x dollars".

  32. #32
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    Re: Tilt and your tech cam - how often with short lenses?

    CNG - welcome out from the lurking shadows!

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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by TEBnewyork View Post
    CNG - welcome out from the lurking shadows!
    Thanks. And yes, I saw the Dante quote.

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    Re: Tilt and your tech cam - how often with short lenses?

    I have not read every word of every post in this topic - but am I allowed to post anyway?

    Quote Originally Posted by Anders_HK View Post

    For a tech camera, it is also absolute important that the lenses be mounted and adjusted for the lens plane to be perfect parallel to the sensor plane (or back mount), and within tolerance to the acceptable tolerance to achieve focus
    Regards
    Anders
    Why?

    I appreciate that you have to work to high tolerances when the light path is different for focusing and taking the picture - as in an SLR.

    Also you need accuracy if you use a ground glass focusing system.

    But, if you use a tech camera without an infinity stop, and you are going to tilt and focus with live view, why do you need accuracy?

    The one situation that I can imagine that would need some degree of accuracy is when pre-setting movements at ground level before cranking my tripod up to ten meters. (Where I would check focus with live view).

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    Re: Tilt and your tech cam - how often with short lenses?

    "But, if you use a tech camera without an infinity stop, and you are going to tilt and focus with live view, why do you need accuracy?"

    agreed, especially with tilts, but even with no tllts i think the conceptual problem is that most seem to want to set their lens on the infinity stop and have objects at 1/4 mile be in best possible focus. After that, they would assume the lens barrel distance markings (and helical fine adjustments) are accurate enough for intermediate distances, also assuming they can figure a way to measure those distances.

    I know what i am going to do when my cambo shows up:

    pop on the back I will be using now with no shimming. fit the 43mm lens, set to the infinity stop and take shots to check focus, figure out how to adjust the lens flange so infiinity sharpness is achieved.

    when the 70mm lens shows up, repeat above.

    when the IQ back shows up, then shim the new back, if required, by checking images ,using the 43 as it is more sensitive.

  36. #36
    Member David Duffin's Avatar
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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by TEBnewyork View Post
    Graham - I think that is a little overly dramatic about how you use the Arca. Most people only have a couple of lenses and any adjustment factor is really quite small and simple to remember. In addition with the wider lenses for landscape you are working with a pretty short range of the focus helical.
    Terry, have you calibrated your Arca Rm3d + whatever back you use with more than one lens? If so I'd be curious to know how consistent your correction factors turned out to be... (thanks, hope I'm not trespassing too much)...

  37. #37
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    Re: Tilt and your tech cam - how often with short lenses?

    Quote Originally Posted by David Duffin View Post
    Terry, have you calibrated your Arca Rm3d + whatever back you use with more than one lens? If so I'd be curious to know how consistent your correction factors turned out to be... (thanks, hope I'm not trespassing too much)...
    I've mainly used the 35XL with the Rm3d and I was not having focus issues. This shot was with about 1 degree of tilt and you can see I'm good close in and if I were to post crops you would see I'm good at the tree tops (and confirmed with focus mask in C1).



    My 90 came much later and between my travel schedule and just messy weather every weekend I have not done any major testing/calibration on the lens and also haven't been unhappy yet. With a better LCD and focus mask on the new IQ backs I'm also not getting too uptight about it.


  38. #38
    Member David Duffin's Avatar
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    Re: Tilt and your tech cam - how often with short lenses?

    Terry, your 90mm must have been perspiring a bit! Love the composition!

    Tomorrow if it's clear here I will be checking a new 150 and a 72 that just arrived ... will see if both are close to the +2 arcafactor applied with 47mm..

    (A little off-topic, sorry)

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