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Re: [OM] Aperture Vibration Question

Subject: Re: [OM] Aperture Vibration Question
From: Jim Brokaw <jbrokaw@xxxxxxxxxxx>
Date: Tue, 15 Oct 2002 23:13:13 -0700
on 10/15/02 12:29 PM, Winsor Crosby at wincros@xxxxxxxxxxxxx wrote:

> I have wondered before.  What is the source of the aperture induced
> vibration with OMs?  Is it in the lens mechanism itself or is it in
> the mechanism inside the camera body that activates the auto
> aperture?  If inside the body I was wondering whether the action
> could be softened by a modification that would soften the action and
> reduce the vibration.  Maybe the  introduction of a resilient
> component in place of a hard one somewhere in the process?
> -- 
> Winsor Crosby
> Long Beach, California
> 

The timing of this action is critical... I don't know how you can slow the
acceleration and deceleration of the moving parts without changing the
timing. If you add in a rubber stopper, or a spring or something, its going
to affect the closing rate or the reopening rate. A resilient piece might
allow parts to vibrate in resonance where a hard stop would not, also.

The slowing the reopening rate wouldn't affect the exposure, but you'd still
get the shock from the quick stop-down (which is necessary, the shutter
can't open until the lens is stopped down) and that -has- to come
before/during the exposure.

Slowing the stop-down rate will have to increase the 'lock time' of the
camera, its already longer than a rangefinder i.e. Leica M-4 etc. (not the
leaf-shutter types though).

Maybe the best way would be to disconnect the mechanism and rig the lenses
to manually stop down... just like 1956 all over again.
-- 

Jim Brokaw
OM-1's, -2's, -4's, (no -3's yet) and no OM-oney... 


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