[Matsu]

Canon's 1.3x 'APSH' is quite a bit bigger than APSC as well. 29x19 I think. Which gives it a square area of 550mm vs about 370mm for APSC. It's performance seems to exactly split APSC and FF, and the main brief for it seems to be a slight telephoto boost for a low-light sport shooter. It'll be interesting to see how long this format survives. I always thought it could make a good DX+ for Nikon's DX mount:

1.) Many of Nikon's DX lenses look like they would cover that frame
2.) A 1.3X doesn't molest the traditional field of view of wide FX primes too much: Or at least the steps seem to move all the lenses up about one, give or take.

21 becomes about 27
24 becomes about 32
28 becomes about 35
35 becomes about 45

Still needs something at the wide end, but it's potentially a bit more convenient than 1.5x for prime shooters.

The DX lenses get real interesting. There's sure to be some vignetting, but if it's passable enough for in camera software correction, then something like a 17-55 would frame closer to 21-70 than 25-82...

Canon probably wouldn't be able to do something like that with their current EF-S lenses because they moved the flange back to keep EF-S lenses off EF cameras. I don't know if there's enough space in the mount for a 1.3x mirror.

On a side note. I think everyone agrees that the current generation 16MP APSC performs very well. A new generation 24MP full frame could incorporate a lot of those advancements and still have both 50% larger pixels and 50% more of them. Should give at least 1 stop better performance when pixel peeping, and closer to two stops when printing large.