<p> Since I own more than one camera, I am now the official family go to guy on this sort of thing, even if I don't want to be, so please bear with me here. My cousin recently bought a Bessa R3M and its rangefinder has become slightly uncalibrated at infinity. She is also reading the photography how to books and she wants to know the following: can she use zone focusing with an uncalibrated rangefinder until she gets the thing fixed and still get a good photo? I am an SLR guy so I had to say I didn't know, but I would try and find out for her, which is why I am here. It seems to me that it should be possible; all she would have to do is cover the rangefinder window with something and know her distances, but I don't want to tell her something that isn't so. So, anyone, is what she is asking me possible or not? TIA</p>