Re: Medium Format Training

[T3D Sam Smith <sam@xxxxxxxxxxxx>]

>  I would like to know what is involved in training a professional
> photographer who is accustomed to meduim format cameras, how to "do" stereo.

First you must establish what your goals are, especially regarding your main
purpose of using stereo in the first place. Is it for realism or effect?
Realism is more strict, as you're trying to duplicate the scene as the eye
sees it. Orthostereo rules would apply here, thereby giving you a defined
stereo base depending on the average interocular distance between eye, and a
taking and viewing optic of the same focal length. ( This is John's
department!)  As for strictly effect, the base can be enlarging or reduced
to bring out certain depth details. Now if you are getting into more
close-up work, then you will also have to follow certain reduced stereo base
formulas. The most popular, though not the definitive is the 30-to-one rule.

> It would seem to me it shouldn't be too difficult to explain to a good
> photographer how to set up his cameras for professional looking stereo images.

I  would actually think it may be more difficult in some aspects, since he
may try to apply a lot of his 2D rules to 3D. A 2D photographer achieves
depth effect through light, composition and focal length. It's almost like
expecting a painter to know how to do sculpture.

> I am most interested in studio work and automobile brochure type images.

At what scale?

>  I would like those of you who know, to tell me what the spacing "formula"
> would be for medium format and if you know of anyone with experience
> synchronizing these things.  My first thought would be to do a straight
> scaling of the film sizes, but what are those? Which dimension of a 24 X 36
> film size do you choose to scale?

Are you referring to the stereo base or is it your subject that is "scaled"?
The stereo base does not change between different formats. A 65mm spacing in
a 35mm stereo camera is the same as one in a MF camera.

>Also, is working in medium format any more
>complicated than what we have with twin 35mm'S?

The main consideration is depth-of-field. An 80mm lens on a MF camera has a
lot less DOF than a 35mm lens on a stereo camera. It is also hard to achieve
a standard stereo base with two twinned MF cameras, as their bodies are
wider. Then again, twinning 35s can have the same problem. This is sometimes
remedied by using longer focal length lenses to compensate, but it can give
you distortions and less DOF.

>  When I get the images back, they will be brought back down to 35mm format,
>so what are the complications there?

Why not shoot BOTH 35 and MF? It seems you're making it more complicated by
duping.

I hope I haven't misinterpreted what you are asking for, there's a lot of
gaps that need to be filled in. What specifically are you shooting? At what
distance? What focal length, stereo base, viewing device? What kind of
photographer? Are your subjects static?
Once these are answered, more detailed answers can be had.

Sam


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