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

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Subject: [Leica] Re: Crude Film/Digital test, Leica/Canon
From: JCB <jcb@visualimpressions.com>
Date: Sun, 07 Mar 2004 14:24:49 -0800

Many folks still believe that different (good) lenses will exhibit 
different properties on digital cameras. They won't. Good lenses (Leica, 
canon, Nikon, Minolta, Zeiss, etc...) will all look alike if used on the 
same camera. The pixel spacing and interpolation firmware (in the camera) 
determine the resolution properties of the resulting photograph. Up sizing 
software (Genuine Fractals, etc.) can make even larger sharp "looking" 
images. Your good lenses are much much sharper than 6 to 9 micron pixel 
spacing on a sensor therefore, it's all in the firmware/software which is 
fooling you into thinking that different lenses on the same digital camera 
make a difference. They cannot. And the same lenses on different cameras 
simply point out how good the firmware programmer, for that camera, is.

Digital is not film. Digital cameras have finite spacing on each recorded 
pixel. Film does not. Silver halide molecules are not only random, but 
there are billions of them within a 1 cubic micron grain. Lots of 
opportunities to record light rays. Lots of levels of density available 
within each one micron, overlapped, silver halide grains. Film is the only 
medium that can differentiate between film camera lenses. True digital 
lenses are dumbed down so that their resolution (MTF) is several times less 
than the 6-9 micron pixel spacing. Digital cameras (SLR's) that take camera 
lenses have a lens resolution (MTF) spoiling low pass filter mounted over 
the sensor. Digital sensors are the great lens equalizer.

When testing lenses on digital cameras for sharpness, you are testing the 
programmer, not the lens.

All of the large prints that you see from ordinary (35mm style) digital 
cameras is testimony to the software wizards that can write interpolation 
software to up-size a minimal amount of information and make it look really 
good. A silk purse out of a sow's ear! Like making a 20x30 print from a 2.7 
MP camera. Basically, it's like slight-of-hand. There simply isn't enough 
information to make a 20x30 from 2.7, 3, 5, 6,... MP sensors. Interpolation 
programmers are magicians. Look up "interpolation" in the dictionary.

You don't have to believe the above. Your prerogative. But it is true, 
regardless.

JB

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Replies: Reply from Jim Laurel <jplaurel@nwlink.com> (Re: [Leica] Re: Crude Film/Digital test, Leica/Canon)
Reply from Rei Shinozuka <shino@panix.com> (Re: [Leica] Re: Crude Film/Digital test, Leica/Canon)