Originally posted by Marc Sabatella No, as I already explained, FF gives you the *choice* of more or less DOF - you can get more by stopping down, less by shooting wide open. That is, FF can take every picture that APS-C can, *plus* the shallower DOF pictures that APS-C cannot.
That's why understanding theory comes in handy - so you don't end up believing something that is actually the opposite of the truth.
However, the price one pays for this is needing fairly large and expensive lenses at the telephoto end to do so.
To get more DOF on the FF, you've got to change distance, fl, or aperture, changes which you don't allow the APS-C to make on the other end.
The second claim, about telephotos, is more complex. If you increase the pixel pitch of the FF to match the APS-c, you lose the large-sensor-site advantage that some FF enjoy, and your statement is true as you can crop to the same size and still get the same MP out. If you don't, the APS-c will always produce more detail, as you can use the same lens on the APS-c that you can use on the FF. This is a factor in long telephoto, and
very important in macro work.