Originally posted by Class A If you read the article, you'd realise that your point doesn't stand.
But it's OK, I don't want to start a debate.
Regarding 645, many people don't need that kind of performance, but would appreciate to use the FF lenses they have to their full potential. So it is definitely not a case of "either go all the way or don't at all".
Even if the points were valid, the current rumor is that the Pentax is going to have a 42 MP BSI sensor. It's going to be quite a bit better than any APS-C sensor.
---------- Post added 07-14-15 at 12:55 PM ----------
Originally posted by Rondec no other size sensor can get as shallow as full frame (unless you go up to film medium/large format).
Picking nits here, but in general medium format is actually slower than full frame. Full frame it's easy to find F/1.4, F/1.2, and even faster in some limited cases... a F/0.95 full-frame lens might be less expensive (and more than a stop faster) than an F/2 MF lens.
Originally posted by Rondec I think the countervailing argument is that if you actually need more depth of field, then full frame does you little good, as once you stop down to APS-C equivalence, you lose your benefit of full frame. That is to say, if you shoot at f2.8 on APS-C and iso 1600 and f4 and iso 3200 on full frame, you will have similar dynamic range, noise and of course depth of field. The only way you get a real benefit is if you are willing to tolerate less depth of field.
A cost, weight and size benefit (full frame is generally cheaper, lighter and smaller at equivalent DOF) are also real benefits in my view.
In terms of picture taken, you're right about DR, noise, and DOF, but in terms of sharpness, CA, etc, the full frame picture is in practice always superior for reasonably comparable lenses.