According to Canon, this will be the world's fastest digital SLR. It will be a 10.1 megapixel work horse. It will run with an ISO range of 100 to 3200 and will allow you to push this from 50 to 6400 if need be.
This camera replaces Canon's Mark II.
Some of the cool new features on the Mark III will include the ability to finally shoot "amateur style" (using the LCD screen rather than having the camera pushed up against your face and composing your shot through the viewfinder). It will also have much needed anti dust technology that actually vibrates the camera when you turn it on or off to keep dust off your sensor.
Dust on the sensor is a common complaint for Canon 5D owners and is a royal pain in the ass. I clean my sensor at least once a week with Sensor Swabs and methanol. Canon also claims the camera handles better in low light.
Canon's EOS 1 series is probably the number one camera that the Pros use. So if you've got an extra $4,000 laying around in April you might want to consider this one.
Canon Mark III Hosted on Zooomr
I'm tempted but $4,000 is an awful lot of money. My 5D handles pretty well for me right now and I actually don't typically need the faster speed. I don't shoot much sports or rapid fire type photography. Generally I take more time to compose my shots. But for the sports photographer this camera will be really nice. The anti dust technology is the most exciting thing about it in my book and I hope that they can incorporate this technology into some of their less expensive models in the future.
Most dust can be taken care of by healing the spots in Photoshop, but sometimes this becomes especially problematic if the dust spot covers an intricate web design on a bridge or something like that. I've had to throw out photos in the past because of dust that I couldn't handle in Photoshop (or didn't want to spend the time to handle).
All in all it looks like a pretty promising offering from Canon. Just not so excited about the price.
CAJ 1-yr chart