Archived posting to the Leica Users Group, 2000/07/29

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: [Leica] Re: Re: Focusing a 280 F2.8???
From: Doug Herr <telyt560@cswebmail.com>
Date: 29 Jul 2000 21:36:52 -0700

On Sat, 29 July 2000, "Miro Jurcevic" wrote:

> 
> The physics are against you all the way. First the mirror goes clunk and
> shakes the entire casting.
<SNIP>
> 
> The main factors in the equation ..... (thanks to Rob)
> 1. Mirror weight
> 2. Shutter travel - vertical or horizontal
> 3. Body construction
> 4. Wind speed - a 1mm movement on the end of your lenses hood is enough to
> destroy film grain sharpness
> 5. Tripod type
> 
>

Miro,

Another parameter in the equation is the design of the mirror damping mechanism.  Olympus SLRs use shock-absorbing pistons, other camera designs use pivot geometry to slow the mirror to a gentle stop before the shutter opens.  They don't all make the mirror whap against the stops at the top of it's swing.

Anyone who's been on this list for long has figured out that the lack of a flopping mirror is one of the M's benefits, but just the fact that the camera is making an impressive noise doesn't nessesarily mean it can't be used hand-held to make sharp photos.  My experience with Leica SLR cameras (Leicaflex, Leicaflex SL, R4s, R4sP, R8) is that the upward swing of the mirror is very quiet and vibration-free, and that most of the noise of the mirror's action is when it flops back down after the shutter has closed.

My experience has been that for moderately slow shutter speeds, as slow as 1/60 sec, my body damps small amplitude, high frequency motions better than a tripod does.  I use a shoulder stock to steady my long lenses and it works extremely well.  For longer shutter speeds, image sharpness is influenced to a greater degree by large amplitude, low frequency motions and this is where the tripod has a very clear advantage.  At shutter speeds between 1/60 sec and 1/15 sec, using a long lens I've had to use both the tripod to eliminate the low-frequency motions and my body to damp the high-frequency vibrations.

This has been my experience.  Your experience is clearly different, possibly with a camera body I haven't used, a tripod I haven't used and using a technique unlike mine.  Your experience is not universal.


Doug Herr
Sacramento
http://ourworld.compuserve.com/homepages/telyt
___________________________________________________
The ALL NEW CS2000 from CompuServe
 Better!  Faster! More Powerful!
 250 FREE hours! Sign-on Now!
 http://www.compuserve.com/trycsrv/cs2000/webmail/