John,
I'm not sure just what he means by flat field lens though I can guess.
As far as astrophotography goes, delivering a flat field, one that is at
the same point of focus on the edges as in the center is paramount
to giving photos that are in focus across the field. Folks will go to
great lengths to acquire telescopes designed to deliver flat fields on
film....since the lens is curved this can be a big problem if not
properly designed. Astro Physics for example has flat field designs
that give pretty good results on 35mm film format. For med. format
or if one is real picky with 35mm they make an accessory that really
does deliver flat fields on film. I don't have a clue how the macro
designs mentioned perform with ragard to field flatness, but if they
are better at this than standard lenses then they should be
preferable. --greg
Date sent: Sat, 21 Nov 1998 01:02:21 -0800
From: owner-olympus-digest@xxxxxxxxxxxxxxx (olympus-digest)
To: olympus-digest@xxxxxxxxxxxxxxx
Subject: olympus-digest V2 #621
Send reply to: olympus@xxxxxxxxxxxxxxx
> Date: Sat, 21 Nov 1998 00:40:12 -0800
> From: "John Petrush" <petrush@xxxxxxxxxxxxx>
> Subject: [OM] Macro lenses for astro work
>
> On another list, a question was asked regarding the best lenses to use on an
> OM-1 for astro photography. I replied Zuikos, of course, and went on to
> describe the merits of the 50 and 90 f/2 macros for wide field shots.
> Another list member replied with the following:
>
> "Never use a macro lens for astrophotography since they are flat field lens.
> While this is exactly what you want for macro photography it is exactly what
> you DON'T want for the stars."
>
> While I do not agree with this point of view, I thought I'd consult with
> this sage body before I make any response. I recall George making some
> critical evaluations in star tests and found these two to be quite good.
> Opinions???
>
> John P
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