Another way to think about this is with macro terminology.

Macro is always expressed as subject magnification at the film/imaging plane. It is the same regardless of the format used. A 1:1 macro lens produces life-size images whether it is with a 1.6x crop camera, full-frame, or medium format.

So my 180mm macro, at full macro, will produce the same life size image with the same DOF and the same perspective on both my 5D and 50D. It only looks larger/closer on the 50D because we're comparing the smaller uncropped image to a larger uncropped image of the 5D. Because the 5D image "shows more", the angle of view is larger. But I can assure you that the lens did its job and produced the same image circle and the same magnification with the same DOF in both cases.