Archived posting to the Leica Users Group, 1998/06/21

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Subject: [Leica] S-1 Digital Camera
From: "Frank Filippone" <red735i@worldnet.att.net>
Date: Sun, 21 Jun 1998 22:55:51 -0700

Before we get all crazy about digital cameras with an 11 stop range, some
basic electronics is necessary...

If you digitize the image with a CCD, using 12 bits for each of red, blue
and green, you get a dynamic range of 1 part in 2 to the 12th or 12 stops
or range.  It does not mean the CCD could record that range or that the
range itself is linear.  It refers only to the electronics digitization
sub-system.  You can expect that this range is NORMAL for any decent
digital camera.   What I trying to say is that the data presented, while it
may and probably is, perfectly accurate, tells you little to nothing about
the ability to record light data.  I have not seen any specs on the
linearity of light to recorded vs. light reflected ny the subject.

BTW, if you want an analogy to chemical film, .....
Velvia has an ASA of 50
Some Kodak emulsion has an ASA of 1600.
This is a 5 stop range.... and I don't even have any light yet!

Be watchful of marketing hype that is meaningless....OTOH, if you are a
catalog shooter putting out 100 rolls a day, go for it!  Everyone else
will!

Thank You
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Frank Filippone
red735i@worldnet.att.net