A lot has been said and written on the web about this issue, and I have read most of it. The original focusing screen of my camera was spotted and slightly cloudy on the frosted underside of the glass screen. I decided to replace the original combination of fresnel and glass screen by a single screen with split image from Rick Oleson : much brigher and sharper image - very happy. ...Until I ran my first test film with the new screen and noticed that everything beyond 3 metres or so seemed to require to focus the lens at infinity or almost. Furthermore, objects at infinity could not be focused properly anymore : those far away objects were split in the split image rangefinder and would require to focus the lens past the infinity mark. So back home I removed the new screen again and added some thin felt underneath it to lift it : this increased the problem. Clearly the screen needs to sit lower -not higher- and I think I have two options to do that :
1- cut the new screen on all sides so it drops IN the VF well and comes to rest on the blade springs (like the old fresnel screen did)
2- remove the front and back rails of the VF well where the screen is resting on now, as well as removing the extremely thin shims underneath those rails (each rail is held by two tiny screws). Hopefully this will seat the screen low enough.
Yesterday I tried to clean the frosted side of the original focusing glass but without success. I guess the humidity (or mold?) has created a transparent but nevertheless slightly milky cloud in the microscopic pits of the glass.
Any thoughts on that or other suggestions are very welcome. Thanks in advance!