tadler
8-Jun-2012, 03:53
i made again more accurate focus tests with my TK 45s (and another 4x5 camera for reference), making a few exposures on both close and distant objects, wide angle lens, aperture fully open, moving the focus 0.5mm in both directions to checking my front-focus problem i have. so yes, this GG definitely has a front-focus problem. however the 0.5mm correction was way too large. i calculated i need to shim the glass only around 0.125 mm or so. now the question is (Bob maybe?), with those little four screws that shim the metal pieces behind the GG, how do i know what amount of turn pushes the glass by 0.125mm? i suspect a whole turn might be too much, but have no clue.
now, i don't feel like spending the whole month turning 1/8 turn, making exposures, sending to lab and then repeating the procedure, just to find out. will be happy to know if there is already the data regarding those little screws.
does anyone know?
thanks,
tal
now, i don't feel like spending the whole month turning 1/8 turn, making exposures, sending to lab and then repeating the procedure, just to find out. will be happy to know if there is already the data regarding those little screws.
does anyone know?
thanks,
tal