Originally posted by Nicolas06 But reality is a bit different. Only at the end of appertures and ISO scale does it truely matter.
Noise levels of APSC, m4/3 or APSC are so good at low iso that it doesn't matter. When I take a landscape at f/8 iso 100 with DA15 or a portrait at f/2.8 iso 100 with FA77 I don't feel like I would absolutely need an FF or MF body for the terrible noise I get.
I understand I could get less noise on FF with a 22mm at f/11 or 115mm at f/4, but this doesn't really matter because the picture I good enough to be printed quite large.
You'd need go past 30x40" to really see an issue and only looking from near distance.
It does only matter if I need to shoot past iso800 on APSC or if I need an apperture larger than my FA77 can handle (f/1.8). And even I'd find a 85mm f/1.4 if I wanted so...
Biggest gain for me with FF is the constant f/2.8 zoom behemoh that give lot of deph control, great AF capabilities and light gathering all with the conveniance of zoom. At the expense of price, weight and size.
The whole point is that a larger sensor benefits people who are pushing the extremes of photography -- they are shooting in really low light situations, they need really shallow depth of field, they are pushing dynamic range to its max, or they are printing/viewing their images really big. As you say, if you are shooting with a K3 at iso 100, unless you have to brighten your photo 3EVs after the fact, you just aren't going to see noise. At iso 800 and above, it is a different story. To me, it is tolerable up iso 3200, but using a little noise reduction may be needed and you certainly can't push your images a lot at the range.
The biggest problem I have with most of this stuff is that it ignores the fact that the improvement in noise and dynamic range is only applicable when you can tolerate less depth of field. If, you are shooting a landscape and it is sunrise and you need to use f8 on your K3 to get the boulder close to your camera in focus and the background in focus too, you will have to use f11 on your K-1 to do the same thing. If you are on a tripod, its no big deal and probably both images will be shot at iso 100, but if you are hand held, you will have to push your iso up a stop on full frame and lose that noise/dynamic range improvement that full frame proponents gloat about.
Overall, Falk is probably right about the shift to full frame and larger sensors. Although the issue to me isn't necessarily the cost of the camera (which will continue to come down), but the cost of the lenses, which continue to be pretty pricey. A K 30 with 18-135 is dirt cheap right now. A K-1 with 28-105 will be over 2000 dollars. And I was surprised at how cheap the K-1 was on release. Certainly APS-C will continue to be around for a fewer more years with a cost differential like that.