ClassicVW@xxxxxxx wrote:
>
> In a message dated 10/18/1999 4:50:38 AM EST, pling@xxxxxxxxxxxxx writes:
>
> > I think the OM4 is center-weighted only in manual mode, that is the reading
> > you see on the viewfinder. In normal auto mode, it is average metering,
> same
> > for OTF and OTC. The thing contributed to center-weight is the second
> mirror
> > not the field of view of the metering photodiode.
> >
> No, No, No. Several people are confusing the terms a bit. This may be because
> Olympus calls their center-weighted metering- " center-weighted averaging
> metering " In the OM-4, the pattern on the shutter curtain is only used for
> manual mode. ( While you spin the shutter or aperture dials preparing to
> choose your manual settings, the reading is off the shutter curtain). In
> "Auto" mode the exposure is Off-The-Film center-weighted averaging *during
> exposure*. Prior to the exposure it guides you by giving you readings off the
> shutter curtain. But exposure is determined by the actual OTF reading. Now,
> in Spot metering, you get only what you spot meter, of course.
> I hope I stated this clearly and didn't further confuse anyone.
Not really. In manual mode, both spot and average, the reading is taken
off the secondary mirror and NOT the shutter curtain!
Thus, the Olympus OM-4(Ti) metering system actually has four "weighting
patterns" for non-flash photography: OT(film), OT(shutter curtain),
OT(sec. mirror) and spot (a very central circular portion of the later).
And yes, because of physical laws involved even non-spot patterns differ
to a degree.
--
Regards,
Emil Pozar
epozar@xxxxxxxxx
http://www.mypage.at/emilpozar
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