Originally posted by LensBeginner That's the point, I knoe for certain my lenses are good enough at 16MP APS-C, but 24? Never tried so can't be sure.
Also, I had to adjust shutter speeds considerably for moving subjects coming from a lower-MP camera (because pixels are much smaller. You want to crop, right?), and I wouldn't want to go even lower.
Yeah but so what? 16MP APSC is already 36MP on FF. You know it works then. For 24MP APSC, you can just look at the crops available on the net, look at the photos, ask the one that now have a K3. If you need to try to know then try. If you think you need to try but doesn't try and then raise concerns, there a bit of inconsistency in your argumentation to me.
The shutter speed is a false argument. You should have the shutter speed that match the intended framing. If you hope for a 300mm shoot using a 300mm lense on APSC you need a 1/500 or faster without shake reduction. That you get your 300mm framing from a 300mm lense, or from a shorter focal length like a 135mm or 200mm, the speed should be at least 1/500. Shake reduction can drastically reduce it as can a tripod/monopod. But from a practical point of view it doesn't change anything to use a shorter focal length and crop or use the proper focal length and not crop for the shutter speed.
Here just as one example a DA50-135, a 80mm shoot and a 100% crop of K3. The reframing is equivalent to 400mm, so 5 time the focal length:
It was 1/250s at f/5.6, for a 400mm on APSC, this mean the speed should have been 1/600s. You see that SR indeed really works.
Most primes and most quality zoom would do it without issue in the f/4-f/8 range.
Anyway I think the discussion is not for your or my lenses. We speak of a 5MP being enough or not and why Canon now has decided to offer a 50MP FF (and 24MP APSC). Our lenses would not be ideal for such body anyway.
This would not prevent for one to buy it, use some Canon primes on it and benefit of the resolution it provide.