You should also try a F3.5 or smaller aperture lenses, I bet the 2
series screen will be the winner. Large aperture lenses are less
affected by a bright screen. I have posted similar test before with
Zuiko 50/3.5.
C.H.Ling
Wm Biesele wrote:
>
> I have done another series of tests of viewfinder brightness and these
> results look much better; I think the flash in the previous test was
> introducing too much variation.
>
> Test goal: To measure the difference in viewfinder brightness between the
> earlier OM cameras and screens (OM1 and OM2) and the later cameras and
> screens (OM2s, OM3 and OM4) by metering the light transmitted through the
> viewfinder.
>
> Test setup: Camera on a tripod with a 50mm1.8 lens aimed at the ceiling. The
> ceiling was illuminated the halogen flood lamps.
> A varimagnifinder was mounted on the camera. Metering was done with a Minolta
> IV-F meter, NOT with the camera meters. The meter has a reflective light
> adapter which meters the same angle of view as a 50mm lens. The meter was
> used to measure the light transmitted through the viewfinder of the cameras
> by placing the sensor head in the cup of the varimagnifinder. Four
> measurements were taken with each combination of camera/screen and
> illumination on the
> ceiling was measured before and after each series to ensure the subject
> lighting did not change.
>
> So this test measured the light transmitted through the viewfinder; the
> camera meters were not used at all.
>
> Metering the ceiling directly (not through the viewfinder) gave a reading of
> F16.6 @1/2 second (ISO800) for all runs. The Minolta meter uses a scale where
> fractional F stops are reported as decimals, easy to understand if the F stop
> is a whole number (i.e. F16) but a little weird on fractional stops (i.e.
> F5.6).
> A reading of F16.5 is half way between F16 and F22, A reading of F5.6.5 is
> half way between F5.6 and F8; if the stop is less the F11 the stop is
> reported as a decimal (i.e. F8.0) so some readings have two decimal points.
> The meter settings were not changed for the viewfinder measurements (1/2
> second ISO800).
>
> OM2s with Beattie Intenscreen gave a reading of F5.6.2 through the
> viewfinder; with a 2-13 a reading of F5.6.2; with a 1-13 F4.0.7.
>
> OM1n with Beattie screen gave a reading of F5.6.8, with a 1-13 F5.6.2.
>
> For you statistics fans the only series which had any variation was the OM2
> with Beattie which gave two readings at F5.6.2 and two at F5.6.3.
>
> Conclusion: The 2-x and Beattie screens brighten the viewfinders by 1/2 stop.
> The OM2s, and by implication OM3(T(i)) and OM4(T(i)) viewfinders are 1/2 stop
> darker than the OM1n and by implication OM1 and OM2(n). The brightest
> viewfinder was the OM1n with the Beattie screen but this requires handheld
> metering or meter adjustments. And the later cameras with later screens are
> as bright as the earlier cameras with earlier screens.
>
> I may put a Beattie screen in a OM1n for situations where I am not relying on
> the camera meter; i.e. macro where I use the meter as a flash meter and
> compensate for magnification. Also if you do night shots by guess and
> experience (as good as metering usually) a similar setup might be useful.
>
> I apologize for the earlier post which did not completely explain the
> procedure or what was being measured.
>
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