Anyone have experience using 35mm tilt & shift ?

Please forgive me for asking this question in lg. format NG. But I'm
hoping that you folks might know more about this, than the people at
smaller format NGs.

I've been invited to be to participate in an architectural project.
The goal is publication. My tools of choice are a 4x5 monorail using
scanned negative color film w/ 4 lenses of 240mm; 150mm; 90mm; & one
shorter. I have the first four. I would have to obtain the shorter
one.

However the financier of the projects wants to use digital. (For
environmental, health, and reasons of economy. [Her opinions, not
mine] Plus she is very skilled w/ Photoshop) Do to the incredibly high
cost of digital for any format larger that full 35mm, we are left w/
no choice other than 35mm or smaller.

1. Of the several 35mm format, or smaller, tilt & shift lenses, do any
give enough shift to actually be of much value for correcting
perspective?

2. Also how does one compose & focus on a mirror that's between the
lens & focal plane w/ the lens shifted? Wouldn't the angle of mirror
being between the lens & focal plane cause distortion or misalignment
of the image between the focal plane & the SLR ground glass?

Oh by the way, I'm basing these questions on the assumption that all
4x5 digital backs are in the >$20K range. I hope I'm wrong. Are there
any <$10K? That would fit the budget, and be ideal.

Thanks for any help John

John McGraw wrote:
 > Please forgive me for asking this question in lg. format NG. But I'm
 > hoping that you folks might know more about this, than the people at
 > smaller format NGs.
 >
 > I've been invited to be to participate in an architectural project.
 > The goal is publication. My tools of choice are a 4x5 monorail using
 > scanned negative color film w/ 4 lenses of 240mm; 150mm; 90mm; & one
 > shorter. I have the first four. I would have to obtain the shorter
 > one.
 >
 > However the financier of the projects wants to use digital. (For
 > environmental, health, and reasons of economy. [Her opinions, not
 > mine] Plus she is very skilled w/ Photoshop) Do to the incredibly high
 > cost of digital for any format larger that full 35mm, we are left w/
 > no choice other than 35mm or smaller.
 >
 > 1. Of the several 35mm format, or smaller, tilt & shift lenses, do any
 > give enough shift to actually be of much value for correcting
 > perspective?
 >
 > 2. Also how does one compose & focus on a mirror that's between the
 > lens & focal plane w/ the lens shifted? Wouldn't the angle of mirror
 > being between the lens & focal plane cause distortion or misalignment
 > of the image between the focal plane & the SLR ground glass?
 >
 > Oh by the way, I'm basing these questions on the assumption that all
 > 4x5 digital backs are in the >$20K range. I hope I'm wrong. Are there
 > any <$10K? That would fit the budget, and be ideal.
 >
 > Thanks for any help John

What is her objection to using scanned negatives? Does she think
developing the film is too destructive to the environment? I shoot 4 x
5 Provira VC 160 (color negative film) and I scan with an Epson 3200.
You should be able to provide digital files beyond your client's wildest
dreams. I'm pretty environmentally conscious, but it seems to me that
developing color negative film for a project of this kind is pretty low
in the scale of environmental degradation. Also, I don't see much
difference in economy when you consider the cost of an adequate digital
SLR which can handle a shift lens.

As to your questions, I can't tell you if any shift tilt lens will work
with one of the standard digital SLRs. But keep in mind that with such
a camera, because of the small format and correspondingly smaller focal
lengths, you get enormous depth of field at the apertures you are likely
to be using. There should be no need to tilt the lens to get everything
in adequate focus. As to shifting, I doubt if you could get what you
get the flexibility you get with your 4 x 5 camera and lenses. You
would end up having to point the camera up and then leave it to her to
correct perspective in Photoshop. That can be done with some
degradation of the image, but it is difficult to preserve the ratio of
height to width for a building so as to accurately represent its
dimensions. Most people don't realize that and assume Photoshop can do
that automatically, but it can't. In most cases, it gets close, but to
get it right for a critical application like architecture requires some
mathematical sophistication and some calculation. A view camera gets it
right just by having the back vertical.

As to your second question, I don't see any reason why a suitably
designed SLR should have a problem with distortion if you use a shift
lens. The mirror just intercepts the light rays and turn them to
project on a screen other than the film plane. But it is possible
vignetting would affect what you saw.<!-- ~MESSAGE_AFTER~ -->