Originally posted by gazonk But some of them are usable on FF as well! Instead of lobotomizing the whole camera, I suggest instead to implement a "variable crop" for DA lenses with the recommended crop showing in the viewfinder (LCD overlay?).
Apparently the Nikon D3 series of cameras (D3, D3s and D3x) all have this feature. DPReview explains how the viewfinder works
here better than I managed to do (see their diagram showing the image circles and various crops). Nikon has implemented an APS-C crop for their DX format lenses (DA in Pentax terms), a 5:4 full frame crop, and a 1.2X crop which is just a bit larger than APS-H. It looks to be controlled by the thumb lever on the upper left side of the diopter
I've never had the chance to look through the VF of a Nikon D3, so maybe this is what they do already, but if Pentax used plastic crop sliders that moved in both the vertical and horizontal axis just behind diopter, or just behind the focusing screen it would allow the user to preview the aspect ratio and size of their output file. This would be super helpful to me as I usually output my files on 8x10 or 8.5x11 photo paper and with the native 3:2 aspect ratio, I have to plan ahead for the fairly aggressive cropping that I have to do. If I don't leave enough negative space in the short dimension of the frame the long dimension gets trimmed too much. I'm getting better at it, but it sure would be nice if the camera could show me.