Originally posted by ckiang
At any given distance, the DoF of say, a 50mm lens at f/2 on a DSLR is smaller than that same lens on a film SLR, assuming you keep subject distance constant.
You are right, of course, but we don't shoot this way.

What is important is field-of-view, and to get the same field-of-view -- at the same distance -- on a partial-frame DSLR, you need a wider lens, and that has more DOF.

If you insist on using the same lens, there are two results. Either you get a cropped view, or you have to move back to get the "same" view. For the latter case, you will have increased DOF.