Hello All, Sorry if this is already on here somewhere, but I did a quick search and didn't come across anything. I'm looking for a f/stop chart that goes down to ridiculous aperture numbers (in the 3 or 4 hundreds). When using my pinhole camera I've just been taking a random exposure time guess and then developing - then making revisions on exposure times based on that. A chart would be nice though. Any help would be great, thanks.