After acquiring a used Tachihara 4x5 field camera I noticed that it just had a plain ground glass focusing screen. So before I shot any film I read up on it and found that Tachiharas came with a ground/matte Fresnel screen and a clear glass cover plate. Ok, I ordered a set ($99) and when I installed it per the directions (matte/GG toward lens and Fresnel toward eye with cover glass on top of that). Two test shots showed that it was focusing sharply on objects closer than what I focused on in the camera! So I checked the film holder with film and it was in spec. at .186". (That specification is .197 plus or minus .007" without a sheet of film.) Then I checked the distance in the camera to the matte surface of the focusing screen and came up with a whopping .049" difference ! ( I used a Brown & Sharpe depth micrometer.) How could this be? So then I noticed that the plastic GG/Fresnel screen bowed in toward the lens and measuring at the sides of the camera back the measurement was still off about .035" off. I know I can shim the focusing screen so that focusing in the center would be within specifications but it does bother me that the screen is not flat. I will contact the seller of the screen to find out if my problem is unique.
So, after that fairly long discourse (or rant, if you prefer) I would like to hear if any other 4x5 field camera users have had similar problems. Any comments or suggestions would be greatly appreciated.
Maurice
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Originally Posted by Gem Singer
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