First pass at measuring transmitted light thru various screens.
Setup was camera without lens mounted on tripod aimed at grey card., T32 was
mounted on camera and set to the high automatic
setting (flash controls light not camera). Two bodies were used, an OM1n tested
with a 1-13 screen and a Beattie intenscreen and
an OM2s tested with a 1-13, a 2-13 and the Beattie. The cameras had a varmagni
finder attached which allowed a Minolta light
meter with the reflected light attachment to fit in the cup. The light meter
was in noncord flash mode.
On the OM1n there was a 0.6 stop difference in the readings between the
screens. On the 2s there was about a between a 0.2 and
0.3 difference between the 1-13 and the 2-13 and about a 0.6 stop difference
between the 1-13 and the Beattie. With the 1-13
screen there was about a 0.3 stop difference between the 1n and the 2s, a
little less with the Beattie.
I'm not real comfortable with the results now; the sample size was small (4
measurements per combination) and the experiment was
very reliant on the T32 giving consistent illumination. I'll try again this
weekend using midday sun instead of the flash.
Your mileage may vary.
Bill B.
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