Its kind of a catch 22. For infinity to be checked with a lens you have to know
that the lens infinity is accurate first. Lens/body collimators I have used
simulate infinity. There is the least amount of error at this setting.
John
C.H.Ling wrote:
> ----------
> > From: John Hermanson <omtech@xxxxxxxxx>
> > To: olympus@xxxxxxxxxxxxxxx
> > Subject: Re: [OM] Mirror/Focus Adjustment (Long)
> > Date: Tuesday, September 29, 1998 10:57 PM
> >
> > Using infinity for mirror angle adjustment is fast and once done there is
> really
> > no need to check anything else (focus at the film plane.) if focus does
> not
> > match there, it would indicate a problem with the flange/back
> measurement (lens
> > mount to film plane) not the mirror angle.
> >
> > John
> >
>
> But I found some difficulty in using the infinity to check focus, since the
> lens "stop" at infinity. I feel that using the matte screen for focusing
> gives me a more accurate result (for lens of 50mm and higher, I always use
> matte screen). I used to rotate the lens focusing ring back and forth for
> focusing (fuzz-sharp-fuzz), if the lens is "stop" at a point I cannot sure
> the focus is dead accurate with the matte screen. (Mr. Herbert Keppler in
> Popular Photography also mentioned the split screen is similar to CCD in AF
> camera, they cannot provide the most accurate focusing result.)
>
> C.H.Ling
>
>
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