----- Original Message ----- From: "Fox, Robert" <r...@aarp.org>
> I'm thrilled with the results! The proofs are properly exposed (surprise > given I was using a flap for the shutter and counting the seconds) on Ilford > XP2 film (iso 400). I used f64 as the base exposure reading, then multiplied > by 6.3, which worked great. Bear in mind that multiplying the f/64 by 6.3 or 6.48 (if you want to be more exact) will give you a reciprocity uncorrected value for the f/stop of your camera. If by any chance you noticed that the longer the exposures the thinner the negatives, that may indicate is time to correct for reciprocity at those levels of long exposures. I'd suggest you take some notes when shooting. Proof print may or may not show up the underexposure, some may even benefit from it!! > Question: my images are all circular, cutting off the corners cleanly of > the square print. Is this because the image circle is too small for the > film? I'm wondering if the circular edge of the front plate is being picked > up on film, since the edge sticks up about 1/4 inch. Any time the corners are "cut" cleanly as you mention, it is probably mechanical vignetting, the front plate is obviously in the way. You could check for mechanical vignetting by opening the rear and aiming the camera to a bright light while having your eye, the corner of the opening (6x6) and the pinhole line up, if you can't see light coming in thru the pinhole, then you have vignetting. Guillermo
