Iskra RF adjustment - an undocumented option!

Discussion in 'Medium Format Cameras and Accessories' started by eumenius, Jan 3, 2006.

  1. eumenius

    eumenius Member

    Jan 6, 2005
    Moscow, Russ
    Medium Format
    Hello friends,

    I've been sitting at home with my sprained knee, so I had some time to adjust the RF in my Iskra. Well, it suffered from a strange thing - infinity setting in it was okay, and on the closer distances the rangefinder failed. When I did examine the lever with adjustable screw on it (on the right of the lens), I found that it has too much sideplay, so I unscrewed it to put a small washer under it. Surprise! The lever has a special profile, so it makes the rangefinder movement non-linear in respect of lens movement - a special pin follows the profile, so it's working like a cam. The end of this cam is split in two, and the split part responds to a close distances. If the camera is carelessly folded with its lens set, say, on 1 meter, the guiding pin can easily bend the split tail of the lever, making the short distance measurement very inaccurate. That was exactly my case. When I carefully straightened the bent part (with a wide screwdriver inserted in split), the rangefinder became normal - I checked it on 1m, 1.2m and 2m, and the numbers on scale were matching the tape measure to film plane. So I decided to post my finding here - I assume the problem can be quite a frequent one just due to RF construction, and I didn't see or hear anything about a separate 1m adjustment point in Iskra. Be very careful with bending - the bent part is thin, so it can break away if bent for too much (but the metal used on my cam is not brittle, I must say).

    Just my 2c.

    Cheers from Moscow, Zhenya