I'm doing a lot of 8x10 contacts of objects/still lives, I want them clean, sharp, clear and almost clinical (some are multiple exposures too). I was thinking of getting a process lens, like an 45cm apo-tessar, would this be a good idea, my other thoughts were a 14 inch Commercial Ektar or an Artar? I don't really need a lens in a shutter (I have a packard) and the exposures are long. I have been using a no-name 12 inch brass rapid rectilinear which is good, but any thoughts, advice?