Know that dilemma well.. We have four different field darkrooms for making tintypes at events (and prints, cyanos, etc..), two plastic versions for modern events or shooting from the car. One that fits into a backpack - a rigid collapsible pvc tent with cover, and a full wood dark box that is period correct for 19th century events. I've always wanted to build a camera that doubled as a developing tank. Have you tried any thing like that Joe? I figure you're most of the way there with those nice pipe cameras. Like a compact Afgan Camera. Haven't tried direct + paper yet, usually reverse them using sulfuric reversal. Great idea for a super compact out and about developing and shooting setup. Keep up the great work!
I built an Afghan-style box camera with integral darkroom, but not a develop-in-camera type, which has been on my project list for a long time. I was at one time thinking about drilling a hole in the side of a plastic developing tank, then use a curved film plane with direct positive paper. Not sure if chemistry would leak out the pinhole, due to surface tension of the liquid? Hmm....
My thoughts were always clear plexiglass behind the pinhole, shouldn't degrade quality too badly.. But I like the thought that if sealed, a small pinhole just might not leak.
No I haven't, because I have so many different pinhole cameras, each with their own focal ratio, I'd need a dedicated chart for each camera. I'd rather just carry a calculator. What I didn't mention in the video is the first part of the equation can be simplified to a single constant (if you always meter at the same f-number, and the camera's f-number doesn't change); this makes for a simple multiplication. I would fix a label to each camera with their "K-factor."