Archived posting to the Leica Users Group, 2001/03/26

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Subject: [Leica] chips
From: Stephen Patriquen <>
Date: Mon, 26 Mar 2001 12:02:52 -0800 (PST)

The CCDs used in most digital cameras used to be made
in 120mm wafers (they may be up to the new 300mm size
by now).

I once had a discussion about them (this is ten years
ago, when the first Kodak/Nikon pro digital cameras
were just out) at Kodak's TEC "country club" research
facility outside Rochester.

Almost all the production CCDs have defective "dead"
pixels, and - sort of like cutting a diamond - Kodak
would cut up the wafer to produce the most efficient
mix of usable chips.

However, it turns out that even back then, some of
these wafers were perfect. That is, they produced a
120mm CCD - equivalent to a piece of 120mm round 
digital film. (So, theoretically, you could make a
full-frame 120 digital back.)

These chips, unfortunately, are worth about the same
as diamonds. It was intimated that these "perfect"
wafers were reserved for the US military, and no doubt
ended up in a geosynchronous orbit over interesting
parts of the world.

I can only believe that in the intervening ten years,
the production techniques have been perfected to the
point that large perfect CCDs are more common and less
expensive. Apparently, still not common enough.

There is a competing technology as well. I believe
CMOS chips are starting to take over in lower-end

I used to have some pretty interesting "discussions"
with Kodak people about the future of digital and
film, the applications of Photo CD (remember it
predates CD-R as a format), etc.

Those were the days.

Steve Patriquen

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Replies: Reply from Dennis Painter <> (Re: [Leica] chips)