Graflex.org

[jmc]

If I have a 4x5 lens that does not offer
a wide enough circle to allow movements,
can I just "think" of the film format
as medium format (say, 2x3, even
though I'm shooting a 4x5 neg), compose
for a 2x3 area in the center of the 4x5
ground glass, allow the vingietting,
and take the shot? Then, I'd just enlarge
cropping out the corners that vingietted,
which were not part of the composition.
I'm asking because I have a 4x5 and I have
a 90mm that does not afford shifting, although the camera itself does. I'm thinking I could compose for the center of the neg, do the shifts, and enlarge for the center.
Thanks.

[Dan Fromm]

[t.r.sanford]

Depending on what you're trying to do, there may be benefit in using front movements and cropping the negative. If you do use the movements, though, you will want your cropped image to be centered on the optical axis of the lens after you've adjusted it -- if you raise the front an inch, that is, you'd do well to define the center of the printable image as being an inch above the center of the film.

Suppose you were using a view camera with a rotating or reversible back to photograph a horizontal rectilinear subject, and you needed to correct for the convergence of its vertical lines.

Now, imagine a 4x5 film cut apart into two 2½ x 5 sheets, with 2½ inches between their centers.

You could set the back of the camera in its vertical position. The two half-sheets imagined above then would be positioned one atop the the other. You now might raise the front as much as 2½ inches to achieve the desired perspective correction, if you were content to use only the bottom half of the negative (=top half of the image).

In determining how tightly to crop, you'll find that the majority of lenses produce a visible image circle larger than the circle within which the image is "acceptable." How much larger is conditioned by the degree of enlargement (if any), and of course, by what you're prepared to accept.