As to the question of how much a FF sensor costs – I am sure someone on here will eventually post that a FF sensor costs 20X as much to produce as a crop sensor. That is a number I hear thrown around a lot. I am skeptical of such things, so I did a little research as to the origins of this number. It seems it was inferred from a white paper written by canon back in 2006.
To me, it seems highly unlikely that the price gap between FF and crop sensor remains today (if it ever truly was) 20X. Lets say that maybe back when the 5D first launched that the FF sensors were very low volume compared to crop sensors. Maybe, just maybe way back then, it could have been. But now, Canon sells lots of FF sensors. And they have had 6years to work out problems in the manufacturing process. The yield rate that used to plague FF sensors – I read that this issue is no longer such an issue, as production tooling has much improved.
Now, the more important question, does it make sense for Canon to drop a FF sensor in a consumer price range camera? I think it will eventually happen. Maybe not in the next couple of years, but eventually. Maybe with Canon’s current product placement, a FF sensor in a low cost package doesn’t make sense, but I think there hand will be forced in this issue because:
What makes more sense is for Sony, or Olympus to drop a nice big fat FF sensor in a consumer body and price it competitively against the top rebel body. Give it equal IQ to 5D mkii and better video features. Also give it really good high ISO performance. This would be a canon and Nikon killer. Hell, I know I would be tempted to switch systems, or let me be more clear – if Sony or Olympus did this, I would switch systems. There profits from the camera body might be pretty thin, but they know that the type of people who would buy the camera would also be buying lenses, and other accessories from them. And before I get flamed by everyone saying that this is not technically possible in this price range – remember technology moves on and things get cheaper and easier to make. I think it is possible to do this and it makes sense for one of the companies on the outside looking in to take a chance on a body like this to win new customers.