Archived posting to the Leica Users Group, 2000/08/23

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Subject: Re: [Leica] Lens challenge
From: Axel Schwieker <axel@baer.rwth-aachen.de>
Date: Wed, 23 Aug 2000 09:18:48 +0200
References: <3.0.6.32.20000822214146.0090f820@pop.microtec.net>

Dan Cardish wrote:
> 
> Check out the last row of images (it will be obvious which ones apply) in
> the portfolio link at http://www.photoartworld.com/leica/.  Try and
> identify Photos A, B, C, and D.

Hi Dan. In this resolution its really hard to find some differences. And
in Addition it seems like you made the pictures with different
apertures. Also the corners of the pictures look fuzzy in all of them,
due to out of focus blur. The only obvious difference is the cool color
balance in picture B, but it's not clear if this is the result of the
lens or of changing lighting conditions or film processing. If this
color cast is due to the lens I would suppose it's the Nikkor.

I suggest a better test picture (yes I know, test pictures are stupid
and boring). My favorite is a tree bark fully in focus on one side of
the picture (distance to camera ~1m) and leafs with out of focus
highlights on the other side. A tree has lots of fine structures to
judge the sharpness. Its important that the tree structure reaches to
the corner of the picture because sharpness in the center is usually
equally good with all lenses, differences show up better at the corners.
The out of focus highlights on the other side show the bokeh of the lens
and, to some degree, might be able to reveal coma and chromatic
aberrations. And because optical performance is more critical at large
apertures (at f/8 performance of all lenses should be equal) you should
shoot with the largest aperture available on all lenses, in this case
f/2.

Regards, Axel

In reply to: Message from Dan Cardish <dcardish@microtec.net> ([Leica] Lens challenge)