A couple of members over at ukBPN asked me to post my views on the 7D, so now having shot ~10,000 images with it and used it intensively in Florida for a week’s birding, here’s my opnions.
First of all, it’s noisy (I’ve said this many times)…however, keep it below ISO400 and it captures unbelievable detail. In other words it needs light!
It works well with good quality glass and prefers apertures below f/8. Anything above this and images start to soften.
I tend to find it does better in low light if you slightly overexpose at the higher ISOs. e.g. using 800 / 1600 and clip highlights slightly, then pull them back in processing.
I reckon there’s ~1.5 stop latitude on highlight recovery which works well with this pull technique. If you underexpose (>1.5 stops) and then try and push process the image, noise and blotchiness creeps in which is hard to process out without loss of detail.
IMO, AF tracking is almost as good as the MkIIN and better than the MkIII (out on a limb here). However, Initial aquistion isn’t as snappy as the MkIII though.
The array of focus modes work well and I do like the micro spot feature, great for nailing small detail. I find that matching the focus array to the size of the subject is good e.g. left, centre or right cluster when tracking larger birds or assist points when subjects are smaller. I shot a 24 frame sequence at Venice Rookery of a flying Heron and the 7D nailed them all…. 
I would add the grip, it makes the camera better balanced for longer teles, however it’s a bit of a chunky square thing and Canon could have done better in the design stakes.
I bought this camera for two purposes, crop factor and video.
The crop factor coupled with dense pixels makes it a great birding camera when using super teles. EF500 = 800mm. Add a 1.4TC and its in hubble land, but AF performance drops off, moreso on initial acquistition.
The video is stunning – full 1920x1080p HD, upto 60fps (1280×720), shallow DOF and reasonably good ISO performace makes the 7D a very capable video camera for the artistic indie film maker on a budget. My lad (studying to be a film maker at Gloucester Uni) was smitten with it and sold all his DV cameras / equipment to buy one.
However, be careful, it’s not a P&S consumer video camera. e.g. Canon HV40. You have to use it prescriptively and set the footage up, with manual focus and exposure.
Low light capability of the video is better than most consumer video cameras, since it uses pixel binning and upscaling to derive the High Def output.
I’m using a Cineform intermmediate codec for .mov conversion, this provide a upsampled 4:2:2 output which edits better than the default H.264 compressed video.
The sound capture is awful, it has auto gain control (not adjustable) and picks up every pop, click and backgroung chatter. Many users buy a Rhode Video mic or better still use a seperate Zoom H4 recorder for audio capture.
I guess Canon wanted to give journalists a tool to capture short video bursts and if you read some of the dedicated video forums (Cinema5D) and Vimeo many (including Canon) are surprised at the take up of these new breed of Canon HD-DSLRs.
Since I have owned my 7D for ~3 months, I didn’t hesitate to sell my 1DMkIIN, I believe it’s better at everthing, period.
The weather sealing seems adequate (yep, i’ve used it in the rain) and the build and sealing is better than the xxD range.
The only downside is file size, ISO400 raw images can exceed 23MB, which means you really need to use 16GB cards. I used 4GB cards while in Florida and was getting ~150 images per card, so lots of swapping!
Here’s my conclusions:
Pros
Great detail in the right (good) light
Excellent AF performance – better than 1dMkIII?
Solidly built, although I’d opt for the Battery Grip
Cropability and good reach.
High Def video for the “thinking” filmaker – great for slow motion as well.
Battery life – when used with grip
The LCD screen – at last one can review images properly
Cons
File size – 23MB per raw – oh well, Hard Disks are cheap enough but CF aint!
Video AF is useless
Poor high ISO – although pull processing helps
So to sum it up, the 7D is a “Jack of all trades” that is exceptionally good value for money.
Would I buy one again? Yes I would.
