Site Sponsors
Page 1 of 2 1 2 LastLast
Results 1 to 50 of 54

Thread: Focusing with tilt

  1. #1
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Focusing with tilt

    I must admit that I become a bit confused by some of the treads here on this site about focusing regarding tilt and the use of a ground glass.
    (It might be due to the fact that I am often, and easily confused, according to my son).
    I have been using manual focusing on different system since about 2005. First on a 1Dsl and 1Dsll with Contax lenses.
    But here the view finder was not optimal for that..

    Then I got a RZ Proll + a D-model and focusing become some thing completely different.
    Especially after I adjusted the position of the ground glass!
    I modified a focus loupe for the camera and it become even more easy to do.

    The I began to use a 4x5 camera and, using ground glass was even more easy. + with a loupe!
    In one of my confused moments I replaced my RZ with a AFDll camera.
    Not much more in focus in the studio after the shift compared to before
    And I am still carrying about 15 kg around on my back out in the nature.

    In this period I also got a Sinar P 8x10 camera.
    And a Hartblei 45mm tilt/shift lens from this forum.
    And 90% of my photos is manually focus.

    But what I never really has understood is the priniple of focusing tilt after a number out of a calculation or table.
    I am to easily confused of my subject in front of the camera to be able to do that.
    And I almost never has my camera aligned horizontal. I mostly point it downwards when I am using tilt.

    I will use the picture below o describe how I focus with tilt.
    And I will use my Hartblei lens as an example.



    First I mace a ruff composition in my view finder. And, the camera is pointing downwards a bit.

    I focus ruffly in the middle of the picture.
    Then I apply about 1-2 degrees of tilt depending on how much the camera leans forward.
    Check focus in center.

    Then starts the process of adjusting tilt.

    I look at the foreground to my view finder and make (if necessary) small adjustment to focus.
    Then with the foreground in focus I adjust my grip on the focus ring so I now have my index finger at 12 clock.
    And since I use f5.6 for focusing it means that one of the small "tabs" on the aperture ring is just under my finger, also at (almost)12 clock.

    Then I shift my view point to a position in the distant focus plane that is easy to see.

    Now I rock the focus ring back and forward to get this distant point in optimal focus.
    Then I feel where my finger are in regard to the "tab" on the aperture ring:
    If it is past 12, then I must tilt a little bit more. "Under Tilt"
    But, if it is before 12, then I have to much tilt "Over Tilt"

    I adjust tilt accordingly to my result, many by half a degree or so, and then do the focus check again.

    After 2 or 3 adjustments both close and distant focus point now lays on the same distant mark on the focus ring.
    Any adjustment of the focus will now shift the plane of focus (ruffly) perpendicular to my chosen plane of focus.

    The I ponder what f-stop I should use, it will decide how "thick" my focus plane will be.

    Then I take the photo, move the focus out and in again, take one more photo, and if the composition feels good,
    I repeat the refocus/take photo process one or two more times.

    With this technique I will walk away from a scene with 40 - 60% good photos, depending on my f-stop.
    And it takes much longer to describe than to actually do it.

    On my Sinar P4x5 or 8x10 I have the benefit of using a loupe which increase the accuracy a lot of the process.
    Yes, I use the same process described above on my large format cameras.

    It is easy. But it requires one act of fait:
    You just have to believe that you actually can use the ground glass for focusing
    Likes 1 Member(s) liked this post

  2. #2
    Senior Member darr's Avatar
    Join Date
    Jan 2009
    Location
    North Florida
    Posts
    981
    Post Thanks / Like

    Re: Focusing with tilt

    I shoot MF because I love the lenses and the slower pace to capture. Tilt has never been that important to me. I find what I want when I am 'one with my gear' and not wrapped up in it. You make some good points. I do love my ground glass and loupe.
    "Creativity takes courage." ~ Henri Matisse
    Darlene Almeda, photoscapes.com
    Likes 1 Member(s) liked this post

  3. #3
    Senior Member
    Join Date
    Mar 2012
    Location
    NYC
    Posts
    333
    Post Thanks / Like

    Re: Focusing with tilt

    Here's a good tutorial on various various view camera focusing techniques. Some of it may be helpful.

  4. #4
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    Well, I feel a greater need to tilt when I use digital compared to film.
    With film diffraction is much less of a problem for me.

    Regarding the link, it is more or less what I do to focus with tilt. Nothing really new there.
    I don't think "Scheimpflug teori" any more. I just visualize my plane of focus and place it where I want it.
    But this method, as in the link, requires one thing, that your ground glass is in its proper place.
    I am surprised how often I find ground glass that is mounted wrong
    So I always check carefully, and if needed shims the ground glass.

    What I really is saying is that I don't understand when somebody says that it is not possible to focus their technical camera by the ground glass.

    Give me an PhaseOne 260, a Arca Rm3di with an sliding adapter with a properly adjusted ground glass,
    and a loupe that has its focus adjusted to the proper plane, and I will ensure you that I can use the ground glass to focus it.

    Of course I understand the problem with ground glass if you are to some degree visually impaired.
    I am getting older my self, which not directly is improving my eye sight

    And on the 260 you could actually use the screen on the back to check your results quick and easy.
    Trying that with my P45+ is just an exercise in frustration

    Ray

  5. #5
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    I also find a quite large need for tilting, due to the high resolution. Better optimisations of the available depth of field can often be had with tilt.

    However, some have a different shooting style, always focus flat and let some parts of the image be visibly out of focus, they may find it more valuable that the plane of focus is ultra-sharp and super-high resolution than that the whole image is perceived as equally sharp. I have got the impression that since the introduction of pancake cameras (which often lack tilt or have it is an expensive add-on) this way to shoot has become more popular.

    Focusing with tilt with a longer focal length (~70+mm) and closer subjects is very easy to do on the ground glass, you don't even need that much magnification. With very wide angles say a Schneider 35mm the edges is very dark (like a 90mm on 4x5" I guess) so it becomes hard to look at the edge, in that case measuring distance to the ground (taking into account camera=sensor tilt) and setting tilt from a table can work better is my experience.

    Simply looking at the camera from the side and visualizing a right-angled triangle between sensor, lens and ground, adjusting lens tilt so the tip hits the ground work well when no table is at hand.

    Flat-focusing at a flat subject like a wall, or focus at infinity can be quite difficult to do with high precision with a ground glass, much more difficult than the nice tilted scene you show in the attached photo. In those cases I have found that a very high magnification loupe is helpful (I use 20x). Very wide-angles are a bit more difficult still due to visible focus breathing and vignetting, those are most easily focused close to center, I sometimes do a "focus and recompose" in those cases, i e point the camera towards the object to focus at so I can focus close to center of the lens, where it's bright and no disturbing focus-breathing, and then compose afterwards. The deep DoF masks any shifting due to recomposing.

    I use these techniques when I focus a landscape scene:

    How to focus a landscape scene

  6. #6
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: Focusing with tilt

    We have been at this point of discussion before .

    http://www.getdpi.com/forum/medium-f...live-view.html

    Have a look to the last page of that thread .

    There was very little response . Now , 4 weeks later we get some very intensive discussions about the topics FOCUS and TILT and SWING with technical cameras .
    I am surprised .
    I appreciate the essays from Jae Moon , Torger and Grayhand as well as the contributions from others .
    It seems , that we have some real "TILT specialists" here and I carefully read all contributions and try to understand .
    But , I must admit , I do NOT understand all formulas and posts and have a more confused understanding of TILT/SWING than before . I find the described techniques all very very complex .
    As mentioned in an other thread , I have attended a TILT/SWING workshop at LINHOF in Munich some years ago . That was when I was shooting LF most of the time .
    I got along very well with the Rodenstock TILT/SWING slide rule from Walter E. Schoen and GG focusing .
    But since I shoot MFD I feel absolutely lost with TILT/SWING .

    I will keep reading all contributions , but up to now , I still feel , its all too complicated .
    Regards . Jürgen .
    -----------------------------------------------------------------------------------
    Likes 1 Member(s) liked this post

  7. #7
    Senior Member
    Join Date
    Mar 2012
    Location
    NYC
    Posts
    333
    Post Thanks / Like

    Re: Focusing with tilt

    One (of many things) to consider when working with a good digital back that has high S/N performance, diffraction isn't the monster we were all taught in Optics 101.

    Up until f16 or so, it isn't actually obliterating detail at the frequencies we care about; it's just reducing MTF. Which means it's reversible. You can stop down to f11 with confidence that 100% of the detail that's apparently lost can be recovered, especially if you use a sharpening tool that makes use of deconvolution (like LR, or Photoshop's smart sharpen filter, or any of the advanced sharpening plugins).

    Even at f22, diffraction is probably a much smaller deal than defocus blur.

  8. #8
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Yes I'd say many are a bit too afraid of diffraction. However while 100% reversible in theory it cannot be done perfectly in practice. The low frequency component in the airy pattern can cause a bleed from light into dark areas, a non-linear contrast loss that is hard to recover. Deconvolution sharpening algoritms only looks at a small blur spot, as it would introduce too many errors trying to reverse it all.

    So at some point there's just too much diffraction to be able to sharpen it well. With current tools I'd say that f/11-f/16 is fine for 6um pixels (60 megapixel backs) probably hard to distinguish on a print after proper sharpening, f/22 there will be some degradation, and f/32 is quite difficult to work with.

    In many scenes tilt allows for a solution with a larger aperture and thus less diffraction. In cases with very close foreground (often due to a low tripod) I sometimes combine tilt and small apertures, say 3-4 degree tilt and f/22 with that you can do magic DoF :-).

  9. #9
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    Nice link Torger, I have not seen that article of you before.

    Jürgen, I think that, in a practical demonstration, I could quickly show you how simple it is to focus by the ground glass on medium format,
    maybe 30 minutes and then you have it clear. And it will be done without any help of external tools or tables. Ones you get it, it become irritatingly simple

    I ones shot a brick wall.
    First att F11 and then at F22 with my Rz and P45.
    And I was really surprised how large effect diffraction had on the quality

    My base line quality requirement for my photos today is that they should be possible to print up to 1x2 meters,
    and that I should be able to stand half a meter from the print without crying.
    If I don't want everything front to back in sharp focus, then I must be able to control focus.
    And if I also want to control the plane of focus, then I must have even more control.

    And regarding the way I work with MY equipment, manual focusing on the ground glass is the ONLY way that I will meet MY requirements.

    And, I have NO opinion on how other people work with THEIR own equipment, I always suppose they do what suits THEM best.
    I hope that was clear enough

    I only become confused when some one says it is not possible to work the way I do
    Likes 5 Member(s) liked this post

  10. #10
    Senior Member
    Join Date
    Mar 2012
    Location
    NYC
    Posts
    333
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by torger View Post
    So at some point there's just too much diffraction to be able to sharpen it well. With current tools I'd say that f/11-f/16 is fine for 6um pixels (60 megapixel backs) probably hard to distinguish on a print after proper sharpening, f/22 there will be some degradation, and f/32 is quite difficult to work with.
    Your estimates agree closely with my own experience, and also with the basic theory.

    Here are some diffraction MTF charts that also consider sensor MTF (theoretical) and defocus blur.







    Anywhere you've got over 10% MTF and not a lot of noise, you should be able to recover a lot of detail.

  11. #11
    Senior Member danlindberg's Avatar
    Join Date
    Aug 2010
    Location
    Spain & Sweden
    Posts
    1,196
    Post Thanks / Like

    Re: Focusing with tilt

    Grayhand, your approach is very similar to mine when I used my Linhof SuperTechnica 4x5 or the Fuji GX680III in the past.

    I just want to add that concerning diffraction I have found that I can push a symmetrical lens atleast one stop further compared to a retrofocused lens.
    Alpa FPS • MAX • TC | Alpagon 32Hr | Helvetar 75 | Schneider 120N | Leaf Aptus II 5 • Leaf Credo 60 | www.danlindberg.com

  12. #12
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by danlindberg View Post
    I just want to add that concerning diffraction I have found that I can push a symmetrical lens atleast one stop further compared to a retrofocused lens.
    Very interesting... I've also got a sense that it differs between lenses how hard diffraction seems to hit, but I have never really made a proper test of it to see if it's a true difference or if it is only in my head . In (simplified) theory it should be no difference, but perhaps there is some explanation why there seem to be?

    Maybe it's about how lenses are optimised rather than if they are retrofocus or not? Many of the Schneiders are optimized for f/11 while I think the Rodenstocks are optimized for f/8 (?).

  13. #13
    Senior Member
    Join Date
    Jul 2010
    Posts
    655
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by torger View Post
    Very interesting... I've also got a sense that it differs between lenses how hard diffraction seems to hit, but I have never really made a proper test of it to see if it's a true difference or if it is only in my head . In (simplified) theory it should be no difference, but perhaps there is some explanation why there seem to be?

    Maybe it's about how lenses are optimised rather than if they are retrofocus or not? Many of the Schneiders are optimized for f/11 while I think the Rodenstocks are optimized for f/8 (?).
    I had thought the rodis were optimized for wide open? On their site it says they recommend you stop down as little as possible. Instead they recommend the use of tilt to keep everything in focus...

    I could be wrong, but I am almost always shooting wide open unless I need to stop down to get more in focus.

  14. #14
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by shortpballer View Post
    I had thought the rodis were optimized for wide open?
    Could be, I don't know, only know that the more modern Rodenstock is optimized for something larger than f/11, and that the less modern Schneider "working aperture" is f/11. (My own shooting style is better suited for f/11 working aperture, so I prefer the Schneider.)

  15. #15
    Senior Member
    Join Date
    Mar 2012
    Location
    NYC
    Posts
    333
    Post Thanks / Like

    Re: Focusing with tilt

    According to Rodenstock they perform best stopped down. Apo Sironar Digital at f11, the newer designs at f8. Wide open performance is impressive though.
    Likes 1 Member(s) liked this post

  16. #16
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: Focusing with tilt

    Quote Originally Posted by Grayhand View Post

    Jürgen, I think that, in a practical demonstration, I could quickly show you how simple it is to focus by the ground glass on medium format,
    maybe 30 minutes and then you have it clear. And it will be done without any help of external tools or tables. Ones you get it, it become irritatingly simple
    Thank you Ray for your kind demonstration offer . I think I will come to Sweden and get you show me your workflow .
    Regards . Jürgen .
    -----------------------------------------------------------------------------------

  17. #17
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    It is interesting to take one step backwards when discussing lenses.

    My most boring lens for my Mamiya AFDlll cameras is the AFD 80mm.
    I bought two of these cameras, so I got 2 of does lenses.
    And both of thous give non-exiting results.
    Yes, if I zoooooom deep in they are sharp and good, just like my old 120 macro.

    But, I am much more interested to how thing looks when I have printed my standard 1x2 meter
    (or what I get depending on how I crop) and nailed it to a wall. (Then diffraction also become less of an issue).
    My two favorite lenses for my AFD are at the moment the 120 macro and the 150 AF.

    But I am still lamenting the utter lack of my RZ system and its lenses since I sold that system two years ago
    Those lenses was special ..

    Ray

  18. #18
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by jotloob View Post
    Thank you Ray for your kind demonstration offer . I think I will come to Sweden and get you show me your workflow .
    No problem, I am quit often in south of Sweden.

    And I also gladly take any excuse to go to the south of Denmark

    And in combination with some nice nature wiev,
    then its a pice of cake, or was it pancake, as in camera

    Ray
    Likes 1 Member(s) liked this post

  19. #19
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: Focusing with tilt

    Should we have a TECH CAMERA TILT CLUB ? ? ?
    I have just joined the tilt world . Will it be an inferno ? ? ?
    Regards . Jürgen .
    -----------------------------------------------------------------------------------

  20. #20
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by jotloob View Post
    Should we have a TECH CAMERA TILT CLUB ? ? ?
    I have just joined the tilt world . Will it be an inferno ? ? ?
    Splendid idea

    Why not name the club "INFERNO"

    Then all here at GetDPI Medium Format will feel right at home

    Ray
    Likes 1 Member(s) liked this post

  21. #21
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: Focusing with tilt

    Regards . Jürgen .
    -----------------------------------------------------------------------------------

  22. #22
    Senior Member alajuela's Avatar
    Join Date
    Aug 2012
    Location
    Shanghai / Miami
    Posts
    552
    Post Thanks / Like
    Images
    124

    Re: Focusing with tilt

    Quote Originally Posted by shortpballer View Post
    I had thought the rodis were optimized for wide open? On their site it says they recommend you stop down as little as possible. Instead they recommend the use of tilt to keep everything in focus...

    I could be wrong, but I am almost always shooting wide open unless I need to stop down to get more in focus.
    Hi this week went out and tested all my lenses DF and Cambo. All at 1.5 and 4 meters and at infinity. At all apertures.

    On the Cambo I have Rodenstock, 28 and 40 and a 70. I am convinced that all 3 perform best between 5.6 and 16 with the peak between f8 and f11. After F16 for example with the focus mask no green.

    If anybody has a different experience - please share.

    Thanks

    Philip

  23. #23
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Sometimes 100% focus check on the back is really useful, even for us hard-core ground glass users . I shot this picture yesterday, 72mm f/11, at first only with tilt (focused on ground glass) and it was sharp all over with a just a liiiiittle sharpnesss fall-off on the left side, probably due to a small slope of the ground.

    This very slight fall-off I could see on the Leaf Aptus screen, and then compensated with a very small amount of swing (less than 0.5 degrees) which brought everything into perfect focus.
    Last edited by torger; 6th April 2013 at 08:18.
    Likes 2 Member(s) liked this post

  24. #24
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    Well Torger, my P45+ is good for many things, buth checking for critical focus on the display is not one of its stronger points

    But it is surprisingly how much you can se on the ground glass once you learnt what to look for, the small shift in contrast when you pass the point of optimal focus.

    I have bought a new shift adapter for use on a 4x5 camera with the graflock back and Mamiya digibacks. Very good price and a surprisingly good quality.
    The only point is that it is equipped with a plastic "ground" glass that which is not so good.
    But I did a quick mount of it on the back of my converted Polaroid 4x5 and with a 150mm lens + my P45+ tethered to my Mac Air.

    I did a sequence of focus shoot, refocus shoot, refocus shoot ...
    And the shoots where all unambiguously with a bit of short focus. Very little variation between the shoots, taken about F8 on an 5.6 lens for 4x5.

    And, focusing with a loupe of course

    But now I will grind a new ground glass for this adapter.
    I am just waiting for the number 600 grit powder from England. The number 400 arrived yesterday.
    So then it is about 15 minutes of boring work and then I will have a very good ground glass, and I will then start to shims the glass for critical focus.

    Then it is time to start focusing at 5.6

    Ray

  25. #25
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    Philip, I have no experience of the lenses in your example.
    But your result seems to match what others have reported after practical tests with this type of lenses.

    It is a dangerous game, better lenses and big pixel backs.
    Generally it all just looks worse the more pixels you have and to check it out at 100%.

    But if you have a 140, 160 and a 180 back on the same camera and lens you can see big differences between how a lens looks on the different back at 100%.
    What is a good lens for a 40 MP back can bee a really bad lens for a 80 Mp back, at least at 100% on the screen.
    But if you print all pictures at the same size, a size that is optimized for the 40 MP back, then you will see some thing different.
    Then it is almost no difference between the pictures from the different backs.

    And one point to meditate over is how much bigger is the printing area for the 80 MP back compared to the 40 Mp back, printed at the same resolution

    Iif you normally don't print over 1 meter your biggest problem is seldom lens resolution, it is mostly bad focus and camera movements.

    But that is maybe just me, all others only have problem with lens resolution

    If you really want to save money on the lens side of the camera equipment, then you should print on Canvas

    Ray
    Last edited by Grayhand; 6th April 2013 at 12:42. Reason: spleluinge or some think like that ..

  26. #26
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    I will shove a picture of the result from my focus test.

    As the picture shows so the true focus point is a bit in front of where I focus with the ground glass.
    And as long the test shows front focus, then it is easy to fix.
    You just have to put some shims material under the mounting points of the ground glass, to lift it up.

    If there is back focus, then it is harder to fix. Then you should move the ground glass closer to the lens.
    But that is normally not so easy, depending on how it is mechanically mounted.
    Then you might have to shims the mount for the digital back.
    And that can be more complicated, ones again depending on the mechanical mount of the digiback.

    BUT, when you do this test with a loupe, make really sure that the lope has its focus on the right plane, on the grounded side of the glass.
    And if you have calibrated the loupe on another ground glass, is the next ground glass you use of the same thickness?
    If your loupe is wrongly adjusted, any atempt to adjust the position of a ground glass can be a real exercise in frustration.
    Can any one guess why I know that

    Ray
    Last edited by Grayhand; 6th April 2013 at 23:44. Reason: English...

  27. #27
    Senior Member
    Join Date
    Sep 2009
    Posts
    1,588
    Post Thanks / Like

    Re: Focusing with tilt

    So, for those of us not keen on maths and graphs, am I correct in thinking that the most basic way to set two points on the best plane of focus using a GG– say a foreground object and a background object – is to focus on one point using the a loupe then tilt until the second point is sharp. Keeping the tilt set, check focus on the first point and tweak if needed?
    I realise this method is not taking into account the wedge of best focus and knowing this is key to getting consistent and predictable results, but is my thinking even in the ballpark to start getting acceptable tilt results?
    Likes 1 Member(s) liked this post

  28. #28
    Senior Member
    Join Date
    Mar 2010
    Location
    Southampton
    Posts
    565
    Post Thanks / Like

    Re: Focusing with tilt

    Yup, the old saying was: focus far, tilt near.
    Likes 1 Member(s) liked this post

  29. #29
    Senior Member
    Join Date
    Sep 2009
    Posts
    1,588
    Post Thanks / Like

    Re: Focusing with tilt

    Great, thanks.

    This is part of the reason why I love the Linhof Techno and using the GG to focus. I'm the kind of person that learns visually and by being hands on. The Techno is a fantastically engineered camera and even though I have to go under a dark cloth to focus and compose, it somehow feels more tactile, intuitive and less nonsense in terms of workflow than pancake cameras foregoing the GG, at least in terms of my sensibilities. The only thing I wish was better on the Techno is a finer pitched gearing for the tilt / swing. Also, the focus gearing is good, but I feel it could be slightly finer as well. Not too much, just a tiny bit.

    As an aside, I recently purchased the new 12x loupe from Linhof & Studio. It has a 1cm square base which makes it very easy to check detail in corners. Plus because of the narrow field of view there is little to zero distortion. I was previously using a 10x Silvestri loupe and it was USELESS for finding focus when tilting because I couldn't get it close enough to the edge of frame to check fine details – things would get distorted and weird when looking through it off dead centre. (I'm shooting mainly with a 6x7cm film back and because the film area takes up the entire GG frame, it's very critical I can see to the edge.) It's amazing how such a small purchase can make such a big difference to getting consistent results and therefore developing an understanding of the technical process.

  30. #30
    Senior Member
    Join Date
    Mar 2010
    Location
    Southampton
    Posts
    565
    Post Thanks / Like

    Re: Focusing with tilt

    I agree the 12x loupe is really nice, and - although it's a very small niggle - that the gearing on the T/S could be finer. That said, they're 95% of what I would like them to be, and the fact that we have 10 degrees of both in such a compact body is great. I've actually grown to like the focus control - I think it's nicely balanced in order to pop things in and out of focus. That said it would be nice if one of the focussing knobs was finer geared so we had a choice between which to use. I've found that applying the 'brake' a little bit to the focussing action can make a difference when wanting to make very fine adjustments.
    Likes 1 Member(s) liked this post

  31. #31
    Senior Member
    Join Date
    Sep 2009
    Posts
    1,588
    Post Thanks / Like

    Re: Focusing with tilt

    Yes, I agree. It's 95% perfect. I was out shooting today and thought that perhaps I'm thinking more of the action of the tilt / swing gears as compared to the ultra, ultra silky rise and fall action on the back it's a little tight – unless you're assertive with it it can be a tad jerky. I think with my Techno this might be because I bought it new and haven't "run it in" yet. How do you find the action on yours?

    Reviewing scanned photos today (I scan using an Imacon 949) I see that my tilt technique has been working well. I'm getting what I want in focus, and that's the main thing! Gotta love the GG for that as I've never really second guessed myself in the field. I'm wondering what the new bright Linhof GG is like compared to my Silvestri GG. If it's brighter and finer grained, it'd have to improve the critical focus hit rate even more...

    Also, I think it was reading one of your posts that I learnt Paula had finally received the new 12x loupe. Thanks for the tip!

  32. #32
    Senior Member
    Join Date
    Mar 2010
    Location
    Southampton
    Posts
    565
    Post Thanks / Like

    Re: Focusing with tilt

    Rear rise/fall is indeed 'silky' smooth - really nicely done. The tilt gearing is nice and smooth. The swing is a bit stiff(ish) I would say - possibly to do with the small size of the knob and gearing perhaps? I sometimes use the 'acute' groundglass - the new brightscreen is a larger version i.e. fresnel + cover glass. The 'acute' screen is really bright but, like all fresnels, once you get off center with a wide angle lens, it gets a tad dark. That said, the new brightscreen is physically much larger than the old acute one (which was a Hasselblad screen in a Linhof holder) so it may not be as susceptible to this effect. From the pictures I've seen the holder seems also to have a redesigned 'top' which may restrict extraneous light from degrading the image. It would be nice to hear first hand from someone using it, at £600 it's too expensive for the college I work at to justify given we have the acute screen (unless it gets dropped on the floor by accident and *ahem* needs replacing ) I did read somewhere (here or on LuLa) of someone who had replaced the Hasselblad 'acute' screen with a Maxwell one (he can make the screens in a variety of focal lengths depending on what lens you use most with it). His screens are great. The 12x loupe is pretty small, but perfect in operation for getting into the corners - far, far better than any of the others I had used previously. Low magnification loupes intended for 4x5, 5x7, 8x10 just don't cut it anymore - which is one reason I suspect that people have had difficulty in the past adjusting to the demands of gg focussing in the digital age. Now, with this loupe (and the acute/brightscreen) it's gotten a whole lot easier, to the point where no one should be afraid of it.

  33. #33
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    The number 600 grit powder arrived from England so I did try to grind my self a new ground glass for my new shift adapter.
    Started with the 400 grit for about 10 minutes and then a quick grinding with the 600 grit for maybe 5 minutes.
    For this quick and sloppy test I must declare the result an success
    Way better than the original plastic ground "glass".
    And quite bright with a nice "snap" to focusing.
    Next time I will do a proper job without scratching the top side of the glass...
    Then I will also do a proper calibration of the new ground glass.



    I made two quick photos of one of my Sinar cameras with two standards mounted on different bearer.
    To the left in the photos is a Sinar F and to the right a Sinar P.
    In the first photo there is no tilt and in the second photo there is a tilt of 10 degrees.

    As can be seen in the photo, for the "F" the tilt gives an rotation point way below the lens.
    This makes the whole lens "fall forward" when tilting.

    For the "P" there is a rotation point in the center of the lens optical axle.
    Depending on the lens it also might be the nodal point for the lens.

    When focusing and tilting in the same scene different things happens to the far and near focusing point as consequences of this two different methods.

    Which is the best? It depends, in my opinion, on the scene I which to take a photo of.
    If there is a middle object on the same plane as I want to put my far and near focus points,
    then I think the "P" has a small advantage for me.

    But if you understand the difference between this two construction, then it really doesn't matter how your tilting mechanism is constructed.
    Observe that I only speaking about tilt and focusing without any other help than the ground glass and a loupe.



    I will later make a detailed description with photos of how I focus this two different bearer.
    But at the moment in a period with to much work. There seems to be some kind of natural law stating that "The more toys you want, the more you have to work".
    This is of course utterly unfair, in my opinion

    Ray
    Likes 3 Member(s) liked this post

  34. #34
    Senior Member
    Join Date
    Mar 2010
    Location
    Southampton
    Posts
    565
    Post Thanks / Like

    Re: Focusing with tilt

    You should try aluminium oxide (rather than silicon carbide, which I think you're probably using?) in 1 - 5 micron size - it's possible to make a groundglass that's virtually grain free up to about 20x. Takes longer than silicon carbide (unless you have access to a lapping table), but worth it.

  35. #35
    Member
    Join Date
    Dec 2009
    Posts
    87
    Post Thanks / Like
    Images
    1

    Re: Focusing with tilt

    Quote Originally Posted by Grayhand View Post


    When focusing and tilting in the same scene different things happens to the far and near focusing point as consequences of this two different methods.

    Which is the best? It depends, in my opinion, on the scene I which to take a photo of.
    If there is a middle object on the same plane as I want to put my far and near focus points,
    then I think the "P" has a small advantage for me.

    But if you understand the difference between this two construction, then it really doesn't matter how your tilting mechanism is constructed.
    Observe that I only speaking about tilt and focusing without any other help than the ground glass and a loupe.



    I will later make a detailed description with photos of how I focus this two different bearer.
    But at the moment in a period with to much work. There seems to be some kind of natural law stating that "The more toys you want, the more you have to work".
    This is of course utterly unfair, in my opinion

    Ray
    Ray:

    A nice way to show the different lens tilt methods.

    The Pulitzer Prize winning photographer, Jack Dykinga, has a book titled 'Large Format Nature Photography', published by Amphoto Book, which shows in great details how to use View Cameras with diagrams and sample photos. It is one of the best books with both technical and artistic explanations on View Camera, in my humble opinion.

    Jae Moon

  36. #36
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by f8orbust View Post
    The 12x loupe is pretty small
    Do you know of a link so one can see this loupe? I've searched previously and not found it. I'm a bit curious to see how it looks. I guess/hope it's larger than my 20x loupe...

    How large is the field of view? 5mm? 10mm?

  37. #37
    Member
    Join Date
    Nov 2009
    Location
    UK
    Posts
    142
    Post Thanks / Like

    Re: Focusing with tilt

    There's a picture here of it sitting on top of the new Linhof brightscreen.
    Likes 1 Member(s) liked this post

  38. #38
    Senior Member Grayhand's Avatar
    Join Date
    Aug 2008
    Location
    Sweden
    Posts
    572
    Post Thanks / Like

    Re: Focusing with tilt

    f8orbust: The plan is to go to smaller and smaller grinding powder, and the I have to sooner or later go for aluminum oxide.
    Mostly to see how far there is reasonable to go. But it is an exercise that becomes more and more boring as the size of the grinding powder is reduced

    Jae Moon: Thanks for the tip, I will look out for the book!

    Ray

  39. #39
    Senior Member
    Join Date
    Sep 2009
    Posts
    1,588
    Post Thanks / Like

    Re: Focusing with tilt

    Rough iPhone pics attached.
    Square base is 1cm square. It's small but fine to use.
    Beer bottle cap for reference.
    TJV


    Quote Originally Posted by torger View Post
    Do you know of a link so one can see this loupe? I've searched previously and not found it. I'm a bit curious to see how it looks. I guess/hope it's larger than my 20x loupe...

    How large is the field of view? 5mm? 10mm?

  40. #40
    Senior Member
    Join Date
    Sep 2009
    Posts
    1,588
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by tjv View Post
    Rough iPhone pics attached.
    Square base is 1cm square. It's small but fine to use.
    Beer bottle cap for reference.
    TJV
    Pic I'd base.

  41. #41
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    The 10x silvestri seemed more like 6x to me, but this one with only 1cm square seems to me to have significantly higher magnification. Maybe I should get one.

    What are the pieces of tape for? Is the focusing ring loose?

  42. #42
    Senior Member
    Join Date
    Sep 2009
    Posts
    1,588
    Post Thanks / Like

    Re: Focusing with tilt

    The tape is crudely applied to keep focus exact. It's not really needed but I've put it there because I'm clumsy when fishing things out of my bag!

    My 10x Silvestri was crap. Too much distortion. I wouldn't say this 12x has dramatically more mag but it's certainly sharper and far easier to use.

  43. #43
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    I mainly use my small 20x, but use my 10x as a tilting loupe, I've detached the base so I can use it as just as magnifying glass and tilt it.

    Inspired by this and recent tilt threads I've updated my article on landscape focusing and added a new section "all-around tilt focusing technique" where I go through the typical iterative method, and go into some practical details around it. I may refine it further the coming days, but here it is:

    How to focus a landscape scene

    The key thing in it I think is the discussion about the near-point which often is hard to focus-peak on using the tilt-knob, as it often happens that the plane of focus turns close to the near-point, keeping it roughly in focus for a wide tilt range (so it's hard to see when you have the right amount of tilt!). You could get into arrangements when it turns around the far-point too, but at least my experience is that it's rare, and instead it's quite common that it turns close to the near-point so one often has to relate to the challenge that occurs.
    Last edited by torger; 16th April 2013 at 02:05.
    Likes 2 Member(s) liked this post

  44. #44
    Senior Member
    Join Date
    Jan 2010
    Posts
    431
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by paulraphael View Post
    According to Rodenstock they perform best stopped down. Apo Sironar Digital at f11, the newer designs at f8. Wide open performance is impressive though.
    That brochure is a bit out of date - as the newest generation HR Rodenstocks (like the 90mm HR 'Alpagon') are not listed in it, and they are definitely best at wide open f5.6 to f8, and clearly degrade due to diffraction at f11.

    If I have the time I'll post examples.

  45. #45
    Senior Member
    Join Date
    Sep 2011
    Posts
    1,069
    Post Thanks / Like
    Images
    83

    Re: Focusing with tilt

    Quote Originally Posted by narikin View Post
    That brochure is a bit out of date - as the newest generation HR Rodenstocks (like the 90mm HR 'Alpagon') are not listed in it, and they are definitely best at wide open f5.6 to f8, and clearly degrade due to diffraction at f11.

    If I have the time I'll post examples.
    +1 ....I find best results in the f8-9.5 range, and 7-8 is nothing to sneeze at.

  46. #46
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Quote Originally Posted by torger View Post
    Inspired by this and recent tilt threads I've updated my article on landscape focusing and added a new section "all-around tilt focusing technique"
    Damn... I thought I was quite good at tilting, but now when I've studied the subject further and learnt some details around axial tilt and realized the great advantage of placing the far-point along the tilt rotation axis I need to rewrite the section.

    Sinar P has asymmetric tilt to make this a bit more practical, but the concept seems to work well with the center-axial Linhof Techno too. Just put the far-point in the horizontal center of the lens (if feasible), and then it's much easier and quicker to get to the desired placement of the plane of focus, hardly no need to iterate.

    If far-point is off-center there's a big risk of getting to the problem that the PoF rotates close to the near-point and tilt-focus-peaking becomes near impossible, which is the case my article now goes into detail and how to work around. I need to keep that case too though, as it's not always feasible to actually place the far-point along the tilt rotation axis.

  47. #47
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    I've heard that some actually prefer to use base tilt that many of the old large format cameras had. Nowadays cameras have axial tilt, or at least approximately so. Can someone explain why this is the case? As far as I can see base tilt would only introduce problems in the tilt focusing process.

    The film-to-sensor distance would increase when tilting, which could have some advantage to make iterative process faster in some focus distance / focal length combinations, but I would guess that it's unpredictable?

    My own guess is that base tilt is solely about manufacturing - it's easier to manufacture such a mechanism, and some of those that have got used to work with it prefer it because they are used to it, rather than that there would be an actual workflow advantage with it.
    Last edited by torger; 18th April 2013 at 07:10.

  48. #48
    Senior Member
    Join Date
    Mar 2010
    Location
    Southampton
    Posts
    565
    Post Thanks / Like

    Re: Focusing with tilt

    Here's a good article from the Ebony website about asymmetrical rear tilt, which is a fairly easy read. Again it emphasises that if you can put the axis of tilt across the far focal point then it makes life easier, since when you tilt the lens (with on axis tilt) the distance between the lens and film plane doesn't change. Obviously this was easier to achieve with rear asymmetrical tilt since you could move the axis of tilt (for the film plane) up and down and place it across the far focus point, wherever you decided it was, and then tilt the rear to change the angle of the plane of focus - but the principle is still applicable (to a degree) if you're willing to use rear rise-fall to make sure the axis of tilt falls across the far focus point.

  49. #49
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: Focusing with tilt

    If you dislike the mathematical approach and are in trouble with the imagination of virtual POF and where to focus (as I do) here is a good supplement for your thumb rules and experience .
    Unfortunately , it is based on GG focusing and control , which I find a pain on the small GG as well .
    http://www.alpa.ch/dms/products/tool...t-201206_E.pdf

    Leica Geo Systems , the maker of the DISTO 5 , should make a hand held TILT/SWING meter , similar to a hand held light meter .
    Ok . . . I know , this will always be a dream . . . Unfortunately .
    Regards . Jürgen .
    -----------------------------------------------------------------------------------

  50. #50
    Senior Member
    Join Date
    Mar 2012
    Location
    Sweden
    Posts
    1,538
    Post Thanks / Like

    Re: Focusing with tilt

    Yes I've finally starting to understand the merits of axial tilts and have started to use them on my Techno whenever I can place the far-point there (speeds up focusing workflow).

    On the Techno like most modern more compact cameras the tilt axis is in the center, but I think that in quite many cases it's feasible to have the far-point along the horizontal center without getting too close to the near-point. Once focused one can make a final refinement step with a far-point placed off-axis farther away, refinement is easy when one is "almost there" at the start.

    However with old-school base tilt the tilt axis is outside the frame, that can surely not be any advantage in any case? Not sure which cameras that actually have base tilt though, haven't seen many of them...

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •