I have an automatic roll paper easil for 20x30", and frankly I'll never use it as an easel. It was a $1 pickup only eBay auction, and works a treat, but I figure if you whack a lens on there you've got one giant camera for paper negs. So I'm looking for a lens that would cover 20x30", preferably at infinity but 1:1 would be alright too. I've done a bit of research into ULF lenses and most of them seem to be rare or expensive, but most of them are both. I'd prefer to keep this an affordable project, at least while I figure out if it'll even work. What are my options for making/finding a lens to cover this format? I dont mind single element, and the aperture doesnt matter too much to me as it would all be under artificial light. If al else fails I'll just go with a pinhole, but a lens would be preferable. So, tinkers, chime in. Are there some books I should look into? What is the main factor that determines the image circle of a lens? Would it be out of the question to have something like this fabricated?