Re: [APML]: Why Om-1

[Clark Mason <cmason@bellsouth.net>]

Kip Peterson wrote:
> 
> 
> Hello from a lurker...
> 
> I've been following the "Why OM-1" thread with great interest, partly
> because I'm an Olympus owner myself, though mine is an OM-2s. I was happy
> to learn that the OM-2s meets at least some of the requirements and
> advantages of the OM-1, like a "bulb" setting which thankfully does not
> require a battery, but unfortunately, there is no mechanical mirror
> lock-up capability on this model. As such, I have a question:
> 
> For those astrophotographers who use a camera which does not provide a
> mechanical mirror lock-up, does the vibration induced by releasing the
> shutter significantly impact the quality of your images? If so, is it
> possible to "hide" the film by holding the telescope's lens cap (or
> something) near the scopes objective, waiting for the vibration to cease,
> then quickly "removing" the cover without deleterious effects to the
> image?
> 
> Just wondering...
> 
> Kip Peterson
> San Diego

Hi Kip,
Generally, a lock-up mirror is most needed when doing eyepiece
projection.  What you describe is the "hat trick" that will most
definitely overcome most if not all your vibration problems.  I use a
TV101 on a GM-11 mount w/ a Pentax K1000 (no handy mirror lock-up) and
have not seen any vibration problems *at prime focus*.  If you have an
off-axis guider, try carefully snapping off a frame in an empty camera
while looking thru your guider.  If you see a lot (yeah, i know it is a
relative term) of vibration, you should really use a lock-up mirror or
the hat trick.  Otherwise, don't worry too much about it.

Clark