[Leica] RD 1 vignetting

[henningw at archiphoto.com (Henning Wulff)]

At 12:35 AM +0100 12/3/08, Didier Ludwig wrote:
>There is a devignetting feature also in other converters like Adobe 
>camera RAW, Lightroom, Aperture et al, but this adds noise in the 
>corner fields. What I am concerned, I never used it as I can live 
>well with vignetting on wide angle shots.
>Didier
>
>
>>If you have the software that came with the camera there is a program
>>to correct vignetting. You type in the focal length of the lens to be
>>corrected and the corners are brightened.
>>Cheers
>>Howard
>
>


The sensor has a certain dynamic range. If you boost the corners (or 
de-vignette) by 4 stops, then the noise in the corners will be like 
going from 200 ISO to 3200 if the center is exposed correctly.

Your best bet is usually to only partially de-vignette, and let the 
corners stay dark. If the corners are down by 1 or 2 stops, it's 
really not that noticeable. What's worse is overcorrecting even to a 
small degree.


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