Re: [APML] Proper Use of Varimagni Finder

[R Torsten Clay <tclay@theriver.com>]

I have found that the varimagni finder is pretty much useless for 
astrophoto focusing- not enough magnification. For focusing piggyback 
shots, I just set the lenses at infinity. 

You can determine if the infinity mark is accurate by attaching tape with
many small marks (ie a ruler scale) to the lens and making a series of
test exposures with a stationary tripod, each time moving the focus
slightly. Then just use the mark that gives the thinnest line on the test
shot.

Torsten

On Sat, 15 Jun 2002, Kevin Wigell wrote:

> I just received a Varimagni finder for my Olympus OM-1. I bought it to
> improve my ability to focus when I have the OM-1 mounted piggyback on my
> scope and using a 50 mm or telephoto lens (I use a KEF for focusing through
> the scope). I've been having great trouble getting good, consistent focus
> with lenses on the camera.
> 
> I'd appreciate any advice for using the Varimagni to focus the lens. I've
> practiced with it during the day on terrestrial objects, but focusing on
> stars is completely different, as we all know. BTW, I have a Beattie screen
> in the camera. Do I just focus with the Varimagni at its highest
> magnification setting (2.5x) until the stars look the sharpest, or is there
> more to it than that? Normally I photograph one f/stop higher than the
> lens's wide open setting.
> 
> Thanks,
> Kevin Wigell
> 
> 
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