« on: February 18, 2012, 10:34:00 AM »
I personally doubt they'll be using the 1D4 system, they'd still have to redesign it from the ground up for a FF sensor anyway. I think it's much more likely that it will get a less robust version of the 1DXs 61 point. In that way they can increase the economy of scale by using essentially the same AF system in their entire FF line up.
No need to redesign anything. The APS-H 1D shared the same 45-pt AF module with the FF 1Ds from Marks I-III. So by extension utilizing the APS-H Mark IV AF module on an FF model would be a simple drop-in as well.
Ummm...no. The fact that they all have 45 points doesn't mean they're the same sensor, any more than the fact that both xxD and xxxD have 9-pt AF means they're the same. In the case of the 1D IV vs. 1DsIII, although the 1D IV has a slightly wider spread relative to the total frame, it's physically a smaller sensor. So, if you just dropped it into a FF camera, it wouldn't have nearly as wide a spread.
Granted, they could drop the 1D IV AF into a new 5-series body, and it would still have better coverage than the pathetic spread of the 5D/5DII AF points.
What you said may be true with the 1D IV and the 1Ds III. However, the older 1D and 1Ds have the same AF sensor size of 8x15mm (hope that I am not wrong here )
I couldn't find the AF specs of the 1D IV and the 1Ds III. However, Canon stated that with the 1D X, they expand the AF from 8x15mm to 8x19mm, so I assume that all older 1 series have the same AF surface, i.e. 8x15mm.