Canon announced a slew of new digital cameras today (as they usually do on the first Monday in September), including the 7D. No, bigger numbers don't mean this is a fancier version of the 5D for the rich kids to play with, instead, it's a $1,700 camera (body only) that is slightly scaled back. Even so, it definitely represents the next step in convergence between still camera and video, coming from the still camera end of things.

Since Canon (like all manufacturers) uses the same chips, processors and lenses across their camera lines, the 7D shares many features and specs with its siblings and represents another six-month incremental improvement in technology (Canon is methodical like that). You can certain read about the big long list of "new" features  (like 1080p24) at any number of sites this AM, but let me cut to the chase: the important difference between the $1,700 7D and the $3,200 5D is the size of the imaging sensor. While the 5D is equipped with a full-sized 35mm imaging chip, the 7D has a much more affordable (and slightly smaller) APS-C CMOS sensor. Why is this important? Well, for one, depth of field control is dependent on three variables and one of those is the size of the imaging plane (see also, Videopia the book, page 170).

The APS-C sensor is the same chip that ends up in their entry-level dSLR cameras, like the Digital Rebel models (which start at $800). Now, don't get me wrong, at 22.5mm, the APS-C sensor is nearly an inch across, which is a good deal larger than the 1/3", 1/2" and even 2/3" sensors found in high-end video cameras. Furthermore, it's only a tiny bit smaller than REDs 24.4mm chip. OK, the 7D doesn't compete with the RED, since it'll shoot highly compressed video and won't use cinematic primes, but still it's a couple of magnitudes easier to use at 1/10th the price. Nice!

References:
* Canon EOS 7D product page
* h/t to Jeff Whitley