Archived posting to the Leica Users Group, 1997/04/27
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LUG-gers all: I recently bought a IIIf rd/st body in (apparently)
excellent shape. For it I have a 50/2 Summicron with the usual
front-element coating marks.
Through several test rolls (color neg) a peculiar phenom is
observable: streaky blue skies (the streaks parallel to the length of
the rolls). It is not constant: most obvious and common at 1/1000,
somewhat less so at 1/500, gone at 1/200 and slower. Test films were
mostly ISO 200, and I rang the changes on mfr and processor, so as to
rule out both. Streaking was NOT evident at 1000th or 500th with a roll
of Royal Gold 25. Curtain-leakage tests* showed absolutely clear frames
- - no leaks. Close examination of the worst frames showed the streaks
extending down from the sky into the foreground subject matter ('tho
much harder to see there).
If it's not the film nor the processing, what could cause this? Only
the shutter and lens are left between subject and film. And yes, the
streaking is on the negs.
In fifty-plus years with cameras, I find this most frustrating.
Anyone have any suggestions as to what's "gang agly"? Private email fine.
TIA,
Stan Yoder
Pittsburgh
* camera pointed wide-open at north sky for 45 secs. minimum with each
curtain in front of film.