I stand corrected. But that's a lot of falloff for a telephoto.
Tom
On Tuesday, June 11, 2002 at 14:22, dreammoose
<olympus@xxxxxxxxxxxxxxx>
wrote re "Re: [OM] long telephoto advice" saying:
> Are you confusing vignetting with central brightness loss? Gary's
> tests say T-stop for the Zuiko is almost f8, which would agree with
> the Modern figure of f8.27. I think the 0.8 stop is the falloff in
> brightness from center to corner.
>
> Tom Trottier wrote:
>
> >Yes, loses .8 stops. Oly has significantly more contrast than any
> >other mirror, but is not as sharp as the longer Questar or Celestron.
> >
> >From
> >( http://brashear.phys.appstate.edu/lhawkins/photo/mp-cat-tests.txt )
> >
> >500/8.0 Zuiko (8/84 pp. 70-71, 130):
> >Actual: 498/8.27, Distortion: 1.040incush, Falloff: 0.8 stops at
> >f/8
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