RE: [APML] Focusing OM-1 - but what about the Nikon F2?

["Richard Klappal" <klappal@xnet.com>]

Find, if they're still available, the F2's astrophotography/microphotography
focusing screen. My systems are Canon, which use a double crosshair on a
clear glass field surrounded by a fine matte; Nikon had one that was very
similar or the same.

Using knife-edge technique, focus on a bright star. (Align star with
cross-hairs; move your eye back-and-forth across the field of view.  If the
star moves in relation to the cross-hair, adjust focus. Repeat until star is
stable relative to cross-hair. The star's image is then focused in the same
plane as the cross-hairs.)

-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Stuart Heggie
Sent: Saturday, 27 November, 2004 21:45
To: Discussion of Film Astrophotography
Subject: Re: [APML] Focusing OM-1 - but what about the Nikon F2?


Duncan, I have read all of Jerry's writings on this topic (and most on other
topics). I am left
with the impression that for my camera lenses I can use the Hartmann Mask
approach with a
winter/summer calibration which I have done. For my scope, I want something
real-time and
repeatable and he seems to be firmly in the KEF camp. Thanks!
Stuart
----- Original Message -----
From: "Duncan Munro" <dmunro@sfu.ca>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Saturday, November 27, 2004 2:13 PM
Subject: Re: [APML] Focusing OM-1 - but what about the Nikon F2?


> Hi. It turns out that Jerry Lodriguss has a whole series of articles
> discussing different methods of focusing:
>
> http://www.astropix.com/HTML/I_ASTROP/TOC_AP.HTM
>
>
> makes for good reading.
>
>
> cheers
>
> Duncan
>
> Stuart Heggie wrote:
>
> >Hey everyone - I want to say THANKS for the dialogue and the friendly
banter too. The focus
> >challenge of a system seems to rise exponentially as f-ratio goes down.
My f/4 newtonian and my
> >f3.5 long lens are really tough to get focused well.
> >
> >I am going to go with a KEF. If this list serves no other purpose (beyond
the pure pleasure of
so
> >many great images) it would be in getting to skip a lot of hassle and
jump to a reliable answer
> >fast.
> >
> >Thanks!!!
> >Stuart
> >
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> >
> >
> >
> >
> >
>
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