DOF & shutter Vibration, in macro photography

[Thalmees]

Hi all,
I was trying to photocopy part of newspaper @ more than 1:1 magnification(but lesser than 2:1), using Rodenstock APO Ronar 300mm f/9.0 on DBM mount, as part of an exercise.
From my experience in MF macro photography, vibration & DOF are plying the major role in destroying a lot of photos. In LF macro photography, and @ that scale(around 1.5:1), I have found it very difficult(if not impossible) to get a usable, sharp film.
I put the newspaper flat on desktop, tilted the huge camera around 45 degrees, adjusted the bellow extension till 1.5:1magnification achieved, focused on the farthest point(shortest below draw), adjusted the tilt/swing dial to zero, then focused on the nearest point(longest below draw). At this point I started to feel trapped in a corner.
(1) The focusing to the nearest point(longest below draw), is not achievable with the fine focus knob(it stopped @ the middle of the area photographed). That mean, the amount of needed tilt, could not be calculated with tilt/swing dial, completely. Even at that position, the dial was pointing toward 31 degrees of forward tilt. When I apply it to the front standard, I was not able to see the image on the GG. But, When I apply it to the film standard, every thing was OK but with massive distortion. The Image Circle of my lens @ infinity(according to camera review) is about 264mm(it should be bigger @ 1.5:1magnification), & Angle Of View of 48 degrees.
I know that 31 degrees of forward tilt is not usual in the real life. But I would like to solve this problem as best as I can. I also realized that, the lens axis may shifted beyond the GG area(with front tilt) so that I could not see the image any more.
How could I proceed to get a sharp photo of the same subject?
(2) I'm using behind lens shutter. And from reading in the archive of this forum, I noted that I've to take care of vibration may created by the shutter. For that, and on the same situation mentioned above(@ 1.5:1magnification & even shorter below draw), I tried to see how much vibration could be created by the shutter. I placed a long slice of light weight paper on the film standard(to observe its peripheries during exposure), and released the shutter @ deferent shutter speed. I noticed that there is vibration @ all shutter speeds(ranging from just noticeable to very clear)according to the mechanism used in releasing the shutter(all with cable release).
Can that vibrations(if kept minimal) ruin the photo? Is it transferable to the film?
From my short experience in landscape photography, I did not feel any problem(on film) in this regard. Could it be a new problem?

Some people who have engaged(long enough) in real life experience, may find this exercise of an odd looking. Appreciating any help in clarification of this situation.
Thanks.

[Ole Tjugen]

Forget about image circle when applying big front tilts: Your lens has an angle of view of 48 degrees, meaning it gives an image out to 24 degrees either side of the lens axis. Applying a tilt of 21 degrees would put the edge of the image circle smack in the middle of your film plane, at 31 degrees your whole film is out in the darkness.

You must either use front fall to get the "cone of view" back in the film area, or rear rise to put the film back in the image area.

Sometimes there's no other solution than to reduce the angle between film plane and subject.

[Paul Moshay]

I don't understand the reason for tilting the camera to photograph a newspaper, why wouldn't you tape the paper to a wall, square the camera to it, and make the exposure. In order to defeat distortion the film must be square to the subject, so in your case, the back and lens must be tilted down 45 degrees, what is gained by tilting the camera in the first place. Is it just an experiment to mangle your brain, or is there something I don't get. Paul

[Thalmees]

Forget about image circle when applying big front tilts: Your lens has an angle of view of 48 degrees, meaning it gives an image out to 24 degrees either side of the lens axis. Applying a tilt of 21 degrees would put the edge of the image circle smack in the middle of your film plane, at 31 degrees your whole film is out in the darkness.
You must either use front fall to get the "cone of view" back in the film area, or rear rise to put the film back in the image area.
Sometimes there's no other solution than to reduce the angle between film plane and subject.

Thanks Ole,
I did not think in rise & fall movements. But I'm sure it'll help.
The situation is suggesting more than 31 degrees, but the fine focusing knob, stopped @ mid point of area photographed(NOT the nearest point). In these extreme situation, how can I proceed to calculate the magnitude of tilt?
You are absolutely correct:

Sometimes there's no other solution than to reduce the angle between film plane and subject.

Thanks soooooo much Ole Tjugen.
Best regards.

[Thalmees]

I don't understand the reason for tilting the camera to photograph a newspaper, why wouldn't you tape the paper to a wall, square the camera to it, and make the exposure. In order to defeat distortion the film must be square to the subject, so in your case, the back and lens must be tilted down 45 degrees, what is gained by tilting the camera in the first place. Is it just an experiment to mangle your brain, or is there something I don't get. Paul

Hi Paul,
Not exactly. This is an exercise of extreme situation that I most probably encounter, in the real work. Of course, I'm mangling my brain(& some repliers here/sorry for that) now, to save my time, effort & money wallet, later.
Thanks a lot.
Best wishes.

[Brian K]

When you state that you are using a DB mounted lens I assume that you are using the Sinar Auto Aperture shutter. Unless you use strobe this is not a good shutter to work with in macro situations. It is a large shutter with large shutter blades. There is a significant amount of mass moving when you fire that shutter and working in macro will magnify that movement in the image. You are best off either using strobe or using a long exposure, like 4-8 seconds and using what we used to call an Arm Strong Shutter. That is cover/block the lens with a blackcard, but don't actually touch the lens or camera, set the shutter to "B", open the shutter with your card blocking the lens, wait for the camera to relax (stop vibrating) and then do your 4-8 seconds exposure, cover the lens with your black card and close the shutter.

As for the tilts, you need to understand Scheimpflug. If the camera is at 45 degrees, the subject is flat on a table at 90 degrees, then the front tilt should be at the point where the axis of the film (45 degrees) intersects the angle of the subject (90 degrees) if you extend those axis out. Basically if the lens is tilted to be halfway between the angle of the film and the angle of the subject, the subject will then be entirely in the plane of focus. It's easy when you are dealing with a flat object, if you now add a vertical object to that flat object, it becomes far more complex.

[Struan Gray]

Another point: how were you holding the rail. My experience with long extensions (albeit with long lenses, not macro shooting) is that a single rail clamp is not really stable enough once you get beyond 18" of rail. Sinar's double rail clamp plate, or a second tripod may well help.

You are also well into the regime where the tripod crown can flex where the legs attach (and most centre columns will flex too). For example, my Gitzo 13xx tripod works fine with the centre column with a 250 mm lens on 6x6, but the torques are so much larger with 4x5 that anything longer than 450 mm is too wobbly, so I swap out the centre column on my Gitzo for a flat plate when using 4x5. A second tripod or a studio stand will help even more.

Finally, APO-Ronars are not wide coverage designs. Worse, they typically get mushy very quickly once the circle of good definition is exceeded, and the mush does not improve much as you stop down. This may be softening your results even more than vibration.

[Thalmees]

When you state that you are using a DB mounted lens I assume that you are using the Sinar Auto Aperture shutter. Unless you use strobe this is not a good shutter to work with in macro situations. It is a large shutter with large shutter blades. There is a significant amount of mass moving when you fire that shutter and working in macro will magnify that movement in the image. You are best off either using strobe or using a long exposure, like 4-8 seconds and using what we used to call an Arm Strong Shutter. That is cover/block the lens with a blackcard, but don't actually touch the lens or camera, set the shutter to "B", open the shutter with your card blocking the lens, wait for the camera to relax (stop vibrating) and then do your 4-8 seconds exposure, cover the lens with your black card and close the shutter.
As for the tilts, you need to understand Scheimpflug. If the camera is at 45 degrees, the subject is flat on a table at 90 degrees, then the front tilt should be at the point where the axis of the film (45 degrees) intersects the angle of the subject (90 degrees) if you extend those axis out. Basically if the lens is tilted to be halfway between the angle of the film and the angle of the subject, the subject will then be entirely in the plane of focus. It's easy when you are dealing with a flat object, if you now add a vertical object to that flat object, it becomes far more complex.

Brian, agree with you.
Appreciate your help.
Your post, stimulated me to try to resolve the problem of vibration @ least partially(see below please). Thanks.
Best regards.

[Thalmees]

Another point: how were you holding the rail. My experience with long extensions (albeit with long lenses, not macro shooting) is that a single rail clamp is not really stable enough once you get beyond 18" of rail. Sinar's double rail clamp plate, or a second tripod may well help.

You are also well into the regime where the tripod crown can flex where the legs attach (and most centre columns will flex too). For example, my Gitzo 13xx tripod works fine with the centre column with a 250 mm lens on 6x6, but the torques are so much larger with 4x5 that anything longer than 450 mm is too wobbly, so I swap out the centre column on my Gitzo for a flat plate when using 4x5. A second tripod or a studio stand will help even more.

Finally, APO-Ronars are not wide coverage designs. Worse, they typically get mushy very quickly once the circle of good definition is exceeded, and the mush does not improve much as you stop down. This may be softening your results even more than vibration.

Hi Struan,
I used three rail extensions(two long & one short) on a single rail clamp, over Sinar pan/tilt head. The distance between the film standard & lens standard, is 72cm(~28"). The tripod is heavy duty.
you are absolutely correct.
appreciate your input. Thanks.
Best regards.

[Thalmees]

The issue of Sinar Auto Aperture shutter & vibrations, is of great debate(reviewing the history of the forum). For my self( and for any body who will agree with me, or any potential user of that shutter), I found a simple way(this is what I think) to reduce vibrations, even at an extreme situation(bellows draw of 72cm). Simply put, the Sinar Auto Aperture shutter, need to be fit with new resilient rubber strips(DON'T REMOVE IT), or just put your own fresh rubber pieces. The discussion(URLs & details) below, is directed mainly toward potential & new users of Sinar Auto Aperture shutter.
If you find me wrong, please correct me.
Appreciating any discussion.

________________________________________________________________________
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After reading the responses here(very informative), I really found my self trapped more in the same corner. Could the shutter causing problem that I could not see? May be!
For that, I searched in the forum, but unfortunately the situation is turning to be more complicated.
One of the threads I read, was this: http://www.largeformatphotography.in...tter+Vibration (Posts# 3,11,14 & 15). The debate there(like other threads), was confirming to me that buying a Sinar Auto Aperture shutter for outdoor photography, is a pure mistake. But, I couldn't notice any problem of vibration with my shutter for almost one year.
Through that thread, I knew there are two rubber strips, almost filling the two vertical grooves of the front face of the shutter. See please, the (convex and resilient) rubber strips on the vertical dimensions of the squared front face of the shutter: http://www.sinarcameras.com/file_upl...shutter_kl.jpg
There function, could be absorbing the vibration created by shutter movement. Some of the posters there, advising to remove them, to be able to put the shutter on the front standard easily with its clip(which hold the shutter in place) is closed down.
My shutter has also rubber strips, and I can put the shutter on the front standard after two trials, only(most of the time).
No need to remove the rubber strips. I remember the first time I took out the shutter. It was very hard. Later, this process became easier. I noticed the rubber strips surfaces turned to be concave and looks not resilient any more. This is the effect of pressure against front standard for long time.
There is another groove(but empty of rubber) in the rear face of the front standard. It is similar to this: http://i15.ebayimg.com/05/i/07/70/14/7c_1_b.JPG
After this brain storming, I thought: Why I do not try to add few rubber pieces(for more absorption of vibration) in that groove & see if the clip(which hold the shutter in place) will close down?
I ended by adding 12 small pieces of rubber, distributed along the four sides of the groove. Even, the shutter can be fit easily & securely on the front standard.
The rubber I used, are of small dimensions(1.5X3mm each), just fit into the groove of the rear face of the front standard. Actually, they are rubber letters used in personal stamps. See the letters plate, beneath the tweezer: http://www.media-land.net/images/art...0/043800A1.GIF
To see if the rubber pieces have done any thing to reduce the vibration, I performed the same primitive test(slice of paper test) I mention it in my first post. The result, was great. The vibrations was reduced dramatically.
I think, any body using this type of shutter(or similar), should consider the following points at least(plus factors of un sharpness out side the shutter issue):
(1) Loose knobs(chick all knobs of the camera before exposure & tighten them again).
(2) Cable release(any excessive movement of the cable release, can be transmitted via its knob to the camera).
(3) Mechanism of releasing shutter(advance/push the cable release slowly, with no interruption, till maximum & hold it there till the shutter close again. Then release it).
(4) Rubber strips(change the rubber strips when become old and not resilient).
(5) Shutter itself(still un avoidable amount of vibration. Can be reduced by considering the above mentioned points).
I appreciate any correction or discussion.
Thanks.