In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] (Rob Studdert) wrote:
> It's only at that price point because it has Leica printed on it, it > will probably be made in Portugal too. The sensor won't be. Since in my day job I play with high-end computer chips (Itanium, Opteron, Power4, etc.) I spent a little time today thinking about the ways chip fabrication and price compare in the two fields. A McKinley Itanium is about 400 square millimetres, and sold for about $3500 each, in quantities of a thousand. The APS-sized sensor in the *istD is around the same size, and sells for about $700 in the same quantities. In both cases, you have to get the silicon area masked, etched and deposited in several layers with zero "significant defects", So the first question is "Why is the *istD sensor so cheap?" Two reasons that I can see: * It required a lot less R&D, because the design is simple and repetitive * It's a bit more resistant to defects, because its feature size is a lot bigger: around eight microns as opposed to about a fifth of a micron. So really small defects can end up having no effect on the CCD where they'd kill the CPU, but big ones will wreck either. But the bigger area of a 24x36mm sensor is a major pain. Defect rates ought to be proportional to area, but that would only happen if the chips were made on infinite-size sheets of silicon. Since they're fitted into 8" circles of silicon, the boundaries make life much harder. Without doing the algebra, I'd guess that the defect rate would go with the 3/2 power of the area. If I'm right, that would make it about 30 time harder to make a defect- free full-frame sensor than an APS-sized one, less a factor for the bigger feature size, modulo the respective companies' abilities at operating their chip fabrication plants. And Intel, who make the Itanium, are about the best in the world at that. So I'll do a bit of research to clarify those figures, but I have no trouble believing that full-frame CCD sensors can cost $7000 each, which would fit well enough with the price of the Nikon pro DSLRs. Leica will charge as much for a camera back as Nikon would for a full body, of course. --- John Dallman [EMAIL PROTECTED]
