[pure-silver] Re: Durst L1200 (condensor) & uneven illumination
- From: Georges Giralt <georges.giralt@xxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sun, 29 Jul 2007 16:25:41 +0200
C.Breukel@xxxxxxx a écrit :
Thanks for all replies on my question!
Last night I indeed confirmed that the "uneven illumination" was
(mostly) due to light fall-off of the lens: when stopping down from f11
to f4 (fully open) the light-fall off in the corners was increased by 1
to 1 1/2 stops, as predicted by the graphs..
So it's nice to get some peace of mind..;-)..that it's largly a inherent
quality of the enlarger lens, and not so much the illumination of the
enlarger,
Thanks again & best!
Cor
Hi !
So I had a few minutes to test my Durst Laborator 1000 with condenser
with the Nikon EL 135 F/5.6. I removed the frosted glass and drafting
paper had in the filter drawer, making the enlarger really brighter.
I was obliged to close down to F:32 in order to be able to use the RH
Designs Analyser Pro without saturation.
At F:32, light fall off is at 0.11 to 0.14 depending to what corner you
measure. These are relative from the center which, obviously reads 0.0.
At F:45 the figures even out at 0.09 to 0.11.
So I think I'll stick to this, and use the enlarger without frosted
glass, and gain that extra stop f light I enjoy with the slow Foma or
Forte papers....
Hope this helps !
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