Winsor Crosby wrote:
.......
That astounded me and I went back to Gary's lens test page and sure
enough the differences occurred even wide open. I know Gary was very
careful in doing his tests, so I was wondering what other mechanism
could be causing the softer results with the OM1.
No, it is the diaphram mechanism. Take a look at any OM and fire it with
the lens off. See that little lever on the right side that flies up and
back with some vigor? That's the thingee that stops down the diaphram by
pushing a lever on the back of the lens. This lever goes through its
full motion no matter what the setting of the lens. Now look at the back
of the lens and push the aperture actuator lever. You will see that it
will go through its full travel no matter what the aperture setting,
although the aperture only closes as far as the setting. Thus, with some
variation in the mechanism in the lens itself, the aperture stop down
mechanism generates pretty much the same vibration with any lens at any
aperture. The reason it causes more trouble with some lenses than others
is a matter of whether it sets off native resonances in the particular
camera-lens-holding mechanism (i.e. hands, tripod, ets.) combo and how
large and long they are.
Maybe Olympus did some shutter refinements that damped things better
when they designed the OM4?
The later bodies are not much better in terms of basic vibration, but
the OM-4(T(i)), OMPC and OM2000 (and to a lesser extent, OM-10 and 20)
change the self timer operation so that the mirror and aperture are
activated at the start of the timer operation, so the vibrations have
all nicely died down by the time the shutter is activated.
Or is it the aperture activation lever inside the camera itself?
Yup.
One advantage the Nik*n F2 had over the OM-1 was both mirror and
aperture lock-up.
Moose
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