Re: [Leica] Oil on Lens Blades: How bad is it?

[Rmusacchio@aol.com]

Oil on the blades of lens diaphragms is a fairly typical sign of use of lenses
in relatively hot weather. As the lubricants warm they flow more easily and
tend to work their way onto the blades. The biggest problem that they cause is
a stickiness that could interfere with normal opening and closing of the
aperture. This is more of a problem on automatic lenses like the R-system
because the blades open and close with each exposure. If they stick open then
your film will be overexposed. If they stick in a closed position, then the
image through the viewfinder will darken.
Since the M-lenses hold their aperture when set, they usually don't have as
much trouble.

Rick Musacchio