Originally Posted by Corran
Originally Posted by RichC
Wot Corran sez!
Things that change the relationship between stuff at different distances in a photo so they look different: (a) moving away or from the subject, (b) staying still but using lenses of different focal lengths.
Things that don't change the relationship between stuff in a photo: (a) cropping a photo, (b) changing the format (e.g. FF vs APS - sensor or film).
Well, check out the photos I posted earlier. The relationship between stuff at different distances doesn't actually change when you use different lenses, only the field of view. And if you match the size of the aperture (actual physical size, not f/number), DOF will be the same as well. Individual lens characteristics will of course be dependent on the lens (distortion, fall-off, rendering, contrast, etc.).
Sorry - you're entirely right. I was momentarily spouting rubbish! What I should have written was "including using lenses of different focal lengths but moving yourself so that the same subject appears identically sized in each photo".