Hi everyone. I am a fairly recent convert to 8x10 photography, after a lot of time spent doing 4x5 and smaller formats. In general, I try to maximize the technical qualities in my work. Art first, of course, but performance is also very important to me. I work as an artist and exhibition printer, and in some recent shows I made murals that were 170x220cm. I am interested in trying to get the best technical results out of 8x10, or at the very least, understanding the techniques for getting the best technical results out of 8x10, so I can either employ them or ignore them for any given picture. I do not intend to enlarge every piece to gargantuan proportions, but I would like to know how best to do so if for a certain piece I would like to.

So. I have found that with my lenses, I get the best image quality at f/16-f/22 with 4x5. In certain narrow cases, f/11 can be slightly crisper, but generally DOF is an issue at that point. Starting 8x10, I tried f/22 as a baseline, and while the results are acceptable, in general the performance upon close inspection is not as good as on 4x5. Obviously the negative is 4 times the size, so it will be better in the end, but I am wondering what the real "best" apertures are for 8x10 with very large enlargements. I understand that maximizing depth of field might require f/64 or greater, but I am guessing that for normal subjects that is quite soft. I know this is hard to generalize about, but assuming a very good modern 8x10 lens like the 300mm f 5.6 Fujinon CM-W (which I have), the 450mm Nikkor M (which I am looking at), what is the optimal aperture for large enlargements? f/22-f/32?