On 11/29/2014 9:20 AM, Rick Beckrich wrote:
Help!
All this 180/200 conversation just reminded me that I have an OMZ 200/4.5
languishing with a non-working diaphragm (stuck wide open).
Any simple cure?
Depends where the problem is. First thing is to take off the mount. The aperture stop down mechanism there has the auto
mechanism tab from the camera and manual button activating a spring loaded ring with a long finger that reaches down
into the innards to link with the actual aperture mechanism. Various things may go wrong there, sticky ring, activation
'finger' jumped out of linkage with aperture, spring jumped of its anchors, broken pivot post, etc. Most of those may be
pretty easily repaired/reset.
I have successfully repaired several such problems on both Oly and other brand
lenses.
OTOH, if the problem is oil on the aperture blades, one must disassemble to the point of taking the aperture mechanism
out and thoroughly cleaning it with a solvent to dissolve the grease/oil.
I have cleaned out a very few sticky and/or gritty apertures in 50 mm OM lenses. Sometimes, it comes back. As I recall
from now ancient posts, the problem is thought to be focusing helical grease that breaks down with age and an oily
component that migrates about. The only sure cure is then complete dis-assembly, cleaning of all oil/grease, then
re-greasing. Not worth the trouble for any but exotic lenses, I'm afraid.
But if one LIKES taking things apart ...
Tinkerer Moose
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What if the Hokey Pokey *IS* what it's all about?
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