Archived posting to the Leica Users Group, 1999/09/26

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Subject: Re: [Leica] Grey Zone
From: "R. Saylor" <rlsaylor@ix.netcom.com>
Date: Sun, 26 Sep 1999 23:04:07 -0400

It's not so much the fault of the film as it is of the fixed aperture of 
the lens. The film plane is like the retina of the eye.

Forget about cameras and lenses for a moment. When your eyes 
go from a bright part of a scene to a dark part, the "aperture" (iris) 
in your eyeball changes automatically, you just usually don't realize 
it. The same goes for focus, which is why some people insist that 
the DOF of the human eye is unlimited. The human eye has spot 
autoexposure and autofocus, but the operation of these features is 
unconscious.

If you attempt to take in the entire scene at once with the naked eye, 
without shifting attention to specific areas, some parts may be 
burned out, and there may be featureless black areas. (Also, parts 
will be out of focus.)

No particular reason to expect much more from film than from the 
retina of the human eye

Richard S..

> It surprises me that film has such poor latitude.  Five stops is only a 32-to-1
> difference in illumination.  The JPEG files on my PC can hold eight stops, as
> can my digital camera.  It's depressing.
> 
>   -- Anthony
>