You mighta want to think of a shift lens as a next-format-up lens. i.e., it
has a bigger image circle than a standard lens, but the same Focal Length, and
thus On-Film Subject-Size.
So a 35mm shift lens is really a medium format, 35mm lens. If you were to
graft one onto a Hassleblad it would produce an image with the FOV of a 21mm
Zuiko, yet cover the entire 60mm x 60mm frame.
The 24mm Zuiko has the FOV of an 18mm Zuiko, but with the FL (and thus on-film
subject size) of a 24mm lens.
When you get to 4x5, the lenses are already designed as shift lenses, so a 90mm
4x5 lens will cover more than a 5x7 frame, but it's designed to allow a
movements for 4x5. Used with a 5x7 back, the lens will cover the 5x7 frame,
but you'll get restricted movements.
You could use a 35mm back on a 90mm 4x5 lens and it would give exactly the same
perspective and FOV as a 90mm Zuiko. You'd just be throwing away about 950f
the usable image.
Skip
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>Subject: [OM] operation of shift lenses
> From: Mike <watershed@xxxxxxxxxxxxxxx>
> Date: Tue, 10 Jun 2003 20:33:18 -0700
> To: olympus-digest@xxxxxxxxxxxxxxx
>
>>
>>
>>the shift lens is basically a lens with a wider field of view that has been
>>cropped. by shifting the lens, you are allowing a different part of the
>>image circle to be in the frame.
>>
>Yes, but with an important difference. The "cropped" area of the shift
>still gives you a full frame on the film. If you just cropped an image
>taken with an 18mm you will get the same view but the image on film will
>be smaller. So you get less information or fewer pixels assuming both
>lenses are similarly sharp.
>
> Did i get that right? Maybe I was just saying what you said only in a
>different way.
>Mike
>
>
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