Hi guys and gals, I'm about to venture into the (hopefully) wonderful world of large-format pinhole photography, and I need a little help from all you fine people here. First off, I'm using an old 5x7 Kodak View Camera No. 2-D (not that it matters), with a bellows extension somewhere between 6" and 14". I bought a set of 3 brass pinholes on eBay. They range in size from 0.34mm to 0.63mm. In order to not waste too much film, I'm trying to figure out a base exposure time for Bergger BFP200. Using the old sunny 16 rule, and calculating my effective F-stop with a bellows extension of 8" as somewhere around f/320 (0.63 / 25.4 = 0.025 inches, 8" / 0.025" = 320), it seems to me that my exposure time in bright sun is between 1/8 and 1/4 second. Even if the true effective speed of the film is closer to 100 than 200, we're still talking about sub-second exposures. Does that sound right to you pinhole guys? I had been assuming that my pinhole exposure times would be in excess of a second, so that I wouldn't need a shutter (just use some sort of opaque material in front of the "lens", remove it to expose, then replace it), but my calculations indicate otherwise. I'd appreciate any advice/confirmation/refutation you can offer, and thanks in advance!