Originally posted by Marc Sabatella That wouldn't be having it all - we'd be giving up the smaller size of APS-C cameras, giving up the advantage in telephoto shooting, and paying quite a large premium for it.
Well, certainly telephoto would lose out (I don't care, actually I rather love wide-angle, so FF is a plus for me!), and the cost would increase, but what exactly would change in size with a FF camera?
(1) The sensor itself would be bigger, but compared to the size of the camera, even a FF sensor is not so big
(2) The pentaprism, focusing screen, and VF would have to be larger, but as film cameras like the ME demonstrate, can still be still be pretty small (modern cameras do have the cheezy flash on top of the PP though)
(3) Lens, mount remain the same (and these, along with the mirror box and pentaprism, are a significant lower-bound on DSLR size)
(4) Mirror would be bigger, but mirror box would likely only be slightly different (the depth is defined for historical compatiblity with the lenses, and the front width is defined by the lens mount; again, film cameras demonstrate that a FF 35mm mirror system can be very small)
(5) Electronics, display, controls, memory card, etc, would all be the same size as APS-C cameras (maybe there would need to be a bit more memory for bigger pictures, but this wouldn't affect the physical size appreciably)
(6) Battery would probably be about the same (I suspect most power is actually used for things like the auto-focus motor and display, and there wouldn't be a significantly higher draw from FF electronics)
I'm not sure why FF cameras from other manuf.s are so freaking huge... (well, granted even their high-end APS-C cameras are huge, so...). I suspect more to support other "pro" features, than the FF format per-se. Also maybe it's simply what the users expect. [Note that Nikon's pro film cameras bloated up immensely in the end too.]