Hi all, I've recently had some problems with a 45-85mm FA lens that I just purchased off of ebay to be used with my Pentax 645n. I was doing a test with Portra 400, my pentax body, this new lens as well as my contax tla 200 flash unit (the little one). I was doing a few tests on AE metering mode, at various focal lengths (45mm, 65mm, 85 mm etc.), at -1, 0, +1 exposure stop settings to see how the new lens would react with the flash. The results kind of have me freaked out, as when I shoot with the wide end 45 or 55 mm there is extreme vignetting as you will see: 45mm 65 mm minor vignetting 55 mm, +1 45 mm My question is: what is causing this vignetting? Granted I have no tested this lens with just ambient light no flash. Another question for those familiar with metering with the Pentax 645n, when I place the flash on top of the camera, does it meter taking into consideration there is a flash unit or does it meter as normal i.e. nothing on top of the flash? Of course I am using the contax TLA 200 in manual mode as there is not TTL communication between the Pentax and the contax. however, do the dials on top of the contax flash unit have any impact on the flash itself? I.e. the 45 mm, 90 mm etc. settings? Or it has no functionality? Any help would be great!!