I pre-ordered the Canon 7D mark II about an hour after it was announced- here's what I'm looking forward to:
1. Ability to consistently use ISO 1600.
With the current 7d, ISO 800 is about the highest I'm willing to go when I'm photographing birds. Using the relatively slow 100-400 f5.6L, I'll be able to bump my ISO up one more stop to 1600. This equates to better real world image quality in less noise at ISO 1600, plus the ability to use a shutter speed twice as fast. 1/250 becomes 1/500; 1/500 becomes 1/1000 when compared to the 7d. In practice, that makes a huge difference in capturing a blurry image of something in motion vs. stopping the action with a fast shutter speed.
2. Autofocus capability using the Canon 100-400 5.6L and the Sigma 1.4 teleconverter.
Being a thrifty photographer, I snatched up a sigma teleconverter for about $100 via Craig's List a few winters ago. My original plan was to use this only with my Sigma 180 f3.5 for macro work. It's a great match with the telephoto macro, giving me consistently sharp images. But for curiosity's sake, I started experimenting by pairing it with the 100-400L. This combination won't autofocus on the 7D. Yes, there are ways to fool the system into making this combination work, but it is still a clumsy solution. I used the 1.4 converter and the 100-400 by focusing manually, but this almost always resulted in front or back focus. The camera's live view, contrast-detect based focus did autofocus, but once again, this was a clumsy, slow way to photograph birds. Ultimately, I never determined if the 1.4 TC- 100-400 combination was capable of creating a sharp imag because I could not determine if the blurry images were a result of missed manual focus or unsharp optics.
The new 7d mark II WILL autofocus with lens-teleconverter combinations that result in an f8 equivalent aperture or wider. I'm hoping that I'll get much better results and more keepers. Yes, autofocus will be limited to the central point only (and surrounding points if using AF-point expansion), but that is better than nothing.
3. Wide-area, 65-point autofocus system.
While photographing Wood Storks at Huntington Beach State Park this past August, I was disappointed with the number of in focus bird-in-flight shots I brought home. Of the several hundred images I captured, only a handful were keepers. I was working with a tricky background, but still, I thought the 7d was up to the task. The mark II's 65 point system, coupled with the ability to custom tune the AI-servo autofocus for different shooting conditions should result in more successful bird-in-flight images.
4. I'll have two camera bodies.
I'm keeping the 7d as a backup- it's still a great camera. When I'm in the field, a 7d mark II will be attached 100-400 for sudden wildlife opportunities, while the original 7d will be paired with either a 60 mm macro or the ultra-wide 10-22 zoom.
The new camera is scheduled to arrive tomorrow- I'll keep you updated.