If there is excess travel in the mechanism, you can slow it after actuating.
This affects the end point, not the timing. There will be the same energy
whether the stop is hard or soft. The effect is basically a choice of
exactly what vibrates and at what frequency / amplitude. To eliminate
vibration you would need an energy converting mechanism like the air damper
on the mirror, but this would almost certainly affect timing. Energy
converting materials, like sorbothane, would not be long term reliable in
this case, I guess.
Has anybody tried assessing differences between OM4 and OM2S in this
respect? There should be one as the 2S has a longer cycle before the shutter
fires, hence the slower MD rate. It's not clear from the documentation if
this cycle time applies only in Program mode or in the other modes also, but
the 3.5 FPS is given as the maximum rate for the camera without a caveat on
mode.
Whether the additional delay is sufficient to materially affect the
vibration amplitude at the point of opening is a different matter, however.
I realise that the stock answer to the question would be "why bother, you
can pre - fire both, so do that", but that is inconvenient and bad for grab
shots.
It would bring a whole new angle to the thread of OM2s - why bother?,
wouldn't it. "Because my lenses work better!"
Julian
----- Original Message -----
From: "Jim Brokaw"
> 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...
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|