I want to shoot in daylight some tungsten film using a filter. Say the film is ASA 200, but the instructions say to rate at EI of 100 with an 85 filter in daylight. So I put the filter on the camera, and use an external meter set at 100ASA and everything is fine. What if I use an internal meter in the camera? Would I set that at 200 because it is metering through the filter? My ultimate goal is to put a gel filter in front of, or behind, the lens of a point-and-shoot camera to see what it can do with this film. I would make an ISO label for the film cartridge (tin foil and electrical tape) to set the speed. The question is, what speed? So many experiments, so little time....!