[pure-silver] Re: Durst L1200 (condensor) & uneven illumination
- From: <C.Breukel@xxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 23 Jul 2007 12:53:51 +0200
Martin,
That's great, I have read about lens fall off, but I never realised it was that
substantial! Thanks for pointing it out!
FYI I used a 80mm Schneider-Kreuznach Componon-S, at f11-f16 (not my working
aperture, usualy between f5.6-f11, but I had to reduce my lightoutput else the
Zonemaster could not measure). A quick search on the internet did not bring
such graphs as the one in your link, but I assume it will be compairable with
the Rodagon?
Thanks & best,
Cor
> -----Original Message-----
> From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-
> bounce@xxxxxxxxxxxxx] On Behalf Of Martin Jangowski
> Sent: maandag 23 juli 2007 12:18
> To: pure-silver@xxxxxxxxxxxxx
> Subject: [pure-silver] Re: Durst L1200 (condensor) & uneven illumination
>
> On Mon, 23 Jul 2007, C.Breukel@xxxxxxx wrote:
>
> > The best I could do is roughly the following:
> >
> > 0.15 0.08 0.16
> > 0.08 0.00 0.07
> > 0.17 0.06 0.12
> >
> > (so the middle put on zero, the other figures representing the very
> > corners and sides). Initially I mistrust the Zonmaster, I mean 0.1 means
> > 1/3 stop and 0.15 1/2 a stop.
> >
> > I find this alot, OTOH I never realy noticed this when printing
> > (probably tells that I am not that a good printer I guess..
>
> These are excellent values! You omitted one information: what f-stop did
> you use for your tests?
>
> Compare the light-falloff diagram of the 4/80mm Rodagon with your values:
>
> http://www.butzi.net/rodenstock/rodagon/80mm.htm
>
> You'll see that the Rodagon looses more than 1/2 stop at the edges when
> used at the optimum stop, more when used wide open (nearly 2 complete
> stops at f4 and 44mm away from the center!) This is completely normal, you
> won't find another lens with (much) better values.
>
> Don't forget that your camera lenses have light-falloff at the edges,
> too.... these lighter edges (with a normal negative-positive process)
> compensate a lot of the light falloff of the enlarger lens. The guys with
> positive-positive processes have a lot more problems, here both effects
> are additive...
>
> Grüße aus Hohenlohe,
>
> Martin Jangowski
>
> | Martin Jangowski E-Mail: Martin@xxxxxxxxxxxx|
> | Netzwerke und Multimedia |
> | Voice: +49 7946/3723 Fax: +49 7946/940791 |
> | Snail Mail: Von-Olnhausen Str. 4 74626 Bretzfeld Germany |
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