I have recently purchased a Toyo 45 AII after having a Tachihara for a number of years. When using my 75mm and 90mm lenses, I get some severe vignetting at the top of the photo (bottom of the viewing screen). The initial set-up of the came ra prior to shooting is done according to the Toyo instructions...red indent at top of lens board carrier. Vignetting occurs with or without filters. Lens boa rds are drilled at the factory. Is this a common problem with TOYO ( I never ha d the problem with the Tachihara)? Is there a quick check to insure that lenses are centered? Will tilts cause vignetting? Thanks