Switar lenses

[Tony Driver]

I had used my rx-4 recently for a shoot and one of the problems I had noticed was for focusing both the 10mm and 25mm rx switar lenses. Although I am a complete novice here, it seemed that when I had measured the focal distance and set it accordingly - say 7 feet - it was out of focus and only became pin sharp when I had refocused at about 30ft to infinity. What's going on?

[Chris Keth]

The lens may need service or it may not be screwed in right to the flange. In either case, the lens is a tiny bit farther from the film than it should be.

 

I had a similar problem with primes on a redrock adapter and I ended up adjusting the flange focal depth 26/100 of one millimeter to correct it. Try removing the lens and cleaning the threads and where it seats to the camera. It could just be some dirt is preventing to from seating right.

Edited November 11, 2007 by Chris Keth

[Tony Driver]

Thanks Chris, I'll look into it. If that's the case - do you think it might be the actual mount is loose, because when I turn it to switch lenses, the mount feels kind of shaky...

Edited November 12, 2007 by Tony Driver