Archived posting to the Leica Users Group, 2001/03/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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 applications. 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 London __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/