Am 26 Apr 99 um 1:02 Uhr schrieb Wayne Harridge:
>The lens does have a fall off in brightness (appears like about 1
>stop difference between the centre and the extreme corners), however
>this is a normal phenomenon for an ultra wide lens. There appears
>to be no difference at different apertures. See
...
I have some data from a "Color Foto" test from 9/89.
The Zuiko was tested against the Zeiss (and Rollei Distagon) 4.0/18
and the Nikon 3.5/18. The Zuiko ended best - naturally.
The max. light fall off was measured (they called it vignetting):
At F 3.5 it is a factor of 2.6
at F 5.6 it is 1.7
and at F 8 it is 1.3
(2.6 means, the center is 2.6 times brighter than the corners).
That is one reason I rarely use my 18 mm with open aperture.
Sharpness and contrast is already pretty good, but fall off is
sometimes annoying.
If I follow this rule, I like my 18 mm a lot.
Regards, Christoph
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Christoph Hertzler hertzler@xxxxxxxxxx
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