Wait for full frame?
OK, this is likely to be a bit muddled, and someone will hopefully put me right. Ken Rockwell's article on the advantages of full frame has got me thinking
I pretty well have a full complement of mid quality lenses.....the usual primes, CZ 16-80. Tammy 18-250, beercan and APO zooms, but as of now no G lenses. Whilst admitting that I can probably do a lot better than I do with my existing lenses, it is very tempting to think of getting some top quality glass, to take one variable out of my shooting, starting with a 70-200/2.8SSM (or the 80/200 if that comes up at a sensible price).
Now, here is the question, which maybe someone can answer. If I waited for a FF body and used my existing lenses, how would the IQ compare with using better lenses and the cropped images delivered by a A700.
Let's take a couple of examples of pairs of lenses which would end up with images having the same field of view. How would the IQ of the 85/1.4G on A700 compare with the 135/2.8 on full frame, or the 70-200 SSM on A700 compare with 100-300apo on full frame? I have a feeling I am going to get an IQ boost across all my lenses, which might well more than make up for the additional cost of the A900 or whatever it is, and I carry around lighter and smaller lenses.
I would have to decide what to do about the loss at the long end, however the IQ from a cropped full frame is presumably going to be the same as that from the same lens on the A700 (give or take a few M. pixels which may or may not matter), so until and unless I need a better long lens I can stick with what I have. Similarly I can keep my 16-80 and 18-250 if I want to, and crop the vignetting off the image and be no worse off than I am now (although my old 24-105 might give better IQ on full frame than the cropped 16-80). Thinking as I write that is a test I could do myself on my 5D but it might not give quite the same results.