The FF issue is really one of the number of finished sensors that can be pulled off a silicon wafer after the burn. A fault rate is expected. APS-C sensors allow many more to be arranged on a standard wafer - and the expected fault rate is economically permissible.
FF is an order of magnitude fewer finsihed items per burn, and a fault rate makes the entire process too expensive unless you can either sell a lot of cameras or consider it a prestige item / loss leader.
Somebody with manufacturing know-how please fill in the specifics, such as wafer mm size, old smaller line utility, etc.
Originally posted by pingflood The MF run isn't for 200 cameras. They stated that they didn't want to sell it in the US because the expected sales _here_ would be 200 units. I'd wager that they are hoping for quite a few more being sold in Japan.
Also, FF isn't as easy as sticking a new sensor in. The manufacturing technology gets vastly more complex once you go past a certain size.