Archived posting to the Leica Users Group, 2004/03/07

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Subject: RE: [Leica] Re: Crude Film/Digital test, Leica/Canon
From: "B. D. Colen" <bdcolen@earthlink.net>
Date: Sun, 7 Mar 2004 17:09:41 -0500

Charts, Smarts - go USE the cameras...If you end up liking the film
results, use film. If you like the digital results, use digital...And
btw, a "test" where you're not using the same lenses...in fact one of
you is using a fabulously good prime and the other is using a zoom?
LOL!! :-)

- -----Original Message-----
From: owner-leica-users@mejac.palo-alto.ca.us
[mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of Félix
López de Maturana
Sent: Monday, March 08, 2004 4:34 PM
To: leica-users@mejac.palo-alto.ca.us
Subject: [Leica] Re: Crude Film/Digital test, Leica/Canon


>A friend bought a 10D and brought it over for a test drive.  I 
>downloaded a test chart and we had at it.  We posted two test charts 
>about 2 meters apart.  I put a 50 Summicron lens on my R8 and he used a

>zoom with a top range of 35 on his 10D (I am not sure what zoom it 
>was).  That gave approximately the same coverage.  We backed up so one 
>chart was dead center and the other one at the edge of the frame.  Took

>a shot at f-8.  I was using Velvia and he saved his in the highest 
>quality jpeg, one step below Raw.  He used manual focus as did I.  We 
>both used tripods and mirror lock-up.  We really wanted to do this 
>outside, but it was raining and
windy.
>Couldn't wait as he was leaving the next day for two weeks vacation.  
>Here are the results of the target at the center of the frame.  We shot

>at f-4, 5.6 and 8.  I used the f-8 version because I thought it would 
>compensate
for
>any focus problem a bit more than the rest. The light in the hallway 
>was quite dim and the exposures at f-8 are about 2 seconds for me and 
>about 1 second for him (ISO 50 vs 100)


Aram

I did some tests in the past comparing different lenses. Main problem
is, always, to get the chart you are photographying exactly paralel at
the film-or sensor- and this is achieved by using a bubble level and
using a completely flat table and attaching the chart there. Secondly
you need placing your camera so that the optical axis hits exactly the
center of the chart. Otherwise the corners will have softness not due to
the camera but to the lack of right centering. You need use the bubble
level for leveling the camera and you need, too, be carefully lifting
the camera in his tripod up to the exact place. It takes trully a lot of
time.

You need natural light if possible measured with a colormeter so that
colors match and metering with incident light meter or bracketing but
everytime you move the camera you need to check again the paralellism.
Not an easy task. In the samples you showed us something went wrong with
the 10D who, inferior to the Summicron, is not that bad. Do again. With
these kind of tests some myths may collaps.

Regards

Felix

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