Welcome to the list, Nils. What, yo never call or write unless you're in
trouble? ;-)
First of all, it's not 'just a 50mm'. The multicoated 50/3.5 is an
excellent macro lens. In nice condition they usually sell for US$125-175
on *Bay.
The 50/3.5 has a sticky diaphram. This is commonly caused by a dirty or
bent mechanism in the back under the lens mount, oil on the actuating
mechanism and/or oil on the blades. I've never worked on this particular
lens, but all I've opened up are similar. It's probably worth while to
take off the rear mount (3 cross-point screws) and take a look at the
rear mechanism. I should be obvious how the DOF button pushes on a long
curved lever which moves a pin, the other end of which goes down into
the lens to actuate the diaphram mechanism.The spring that pulls the
diaphram open is there too and has been known to come loose. If that
all works smoothly, but the blades don't move, it all depends on your
skill with small mechanical mechanisms, tools available and courage. It
is possible to clean these up yourself, if you are adept at that sort of
thing. These instructions for the 50/1.8 should give you a general idea
of what is involved
<http://olympus.dementia.org/Hardware/50mm_cleaning.html> . Even if you
don't want to work on it yourself, having it cleaned and adjusted is
probably worthwhile for this lens if the glass is all unmarked..
On the 28/3.5, you have lost or displaced the aperture detent ball
bearing. If you look on the back of the aperture setting ring, you will
see small depressions underneath the aperture markings on the front. In
the lens below where these depressions lie, there is a small hole which
should contain a spring with a small ball bearing on top of it. The
bearing pressing against the setting ring and dropping into the
depressions is what provides the click stops. If the ball bearing (and
spring) fell out of place into the lens proper, you may be able to find
and replace them in proper position (and replace the gucky, dried up
grease for smoother action). Playing hide and seek with tiny parts on
the rug/floor and all over an untidy desk is always such fun. The lens
will work fine without the ball bearing and spring, it just has no
detent action. Some people who are intent on setting exact apertures
intentionally weaken or remove the detent action.
Moose
Nils Frohberg wrote:
hi!
here goes my first post to this amazingly active list!
i got a few new lenses from my dad a short while ago, and i have a few
slight problems with the 50/3.5 macro and the 28/3.5:
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