I hope that it's OK to post a link to another forum but I didn't want to post it all again as it is pretty long. I did a comparison between my 1DmkIII and 7D when I first had the 7D, doesn't cover everything but hopefully helpful.
http://photocamel.com/reviews/canon-cameras/p109-canon-7d.html

Generally I find it very good, initial focus is both very quick and accurate, the one area I find it's lacking (certainly with mine) is servo tracking when panning a fast moving object (car, bike or bird etc.) that crosses diagonally where the diagonal angle is slight, say (guessing here) less than 45 degrees....
what I mean is if the object is coming straight on or going staright away, no problem, if the object is coming slightly on or away then the servo doesn't track the subject accurately, often resulting in out of focus images shot in drive mode after the initial focus point, it's like it's missing the small changes in focus and therefore isn't correcting for them, err.....see?
In practise this means that I'm now much more selective about where I start and finish the burst, the shorter the pan and burst the more keepers I get, a long pan and burst will result in say the first 2-3 frames in focus and the remaing frames getting progressively out of focus up to the last frame which is usually a mile off.
Now don't take this as Gospel, I'm an amateur and it's entirely feasible that it's all down to settings and operator error. Despite my best efforts however I've still not "resolved" this issue, despite working heavily on my panning technique and changing settings and lenses etc. If somebody wants to step in here and point out the error of my ways, I'm all ears![]()
The 10fps is a capability that isn't viable in all situations but it's there because it can be used effectively in some situations......what i cant underatand is why we have 10fps when the cant be used efectively
The 10fps is a capability that isn't viable in all situations but it's there because it can be used effectively in some situations.
Bob
Re the post by Buggerluggs
I too have same problems with my 7d for tracking to the point now that I take my 50d with me for doing that job and can get better reslts with it and more keepers.
When I first got it I, and others, had problems with AI Servo because we had misinterpreted the manual (or maybe hadn't read it properly). So I started by changing C.Fn III-1 to 'Fast' because I obviously wanted my AF sensitivity to be fast. It took a while before I realised that I really wanted it towards the 'Slow' end for BiF.
Rajkay said:I was very worried when I first got my 7d as I always had used the center af point-recompose with my Sony A300, however, with the 7d I had loads of oof shots using the same method, till I started using the outer points using the joystick. I haven't looked back since!
Share your expieriences of 7d focusing, good and bad. Some say its good, some bad and others say its due to user error...what have you found?
I have never had a problem with the 7D autofocus that cannot be attributed to user error.
I have, however, found it to be streets ahead of any previous camera I have had. Lock on is fast and the tracking is superb. I was shooting bikes on Friday on a fast corner and it never missed a beat.
I also shot from a spot where the bikes were panning but getting slightly further away on the bend. No problem.
I think the issue described above with the pan only occurs when you shoot a burst - which is unsurprising really as the af sensors have to be moved out of the way as each frame is fired. I guess it will be more of a problem if the rate the subject is coming towards you/moving away changes part way though the burst too.
Good argument for shooting the frame you want rather than a series though! I rarely fire off more than 1 or two frames when panning anyway so never had an issue.
I constantly try different individual points, or different areas. But I find using a single point only has a tiny area in focus while the auto select will select a larger area if the whole of the subject is the same distance!
hollis_f said:One common cause of focus problems is to focus using the centre point, then to recompose by pointing the camera in a different direction. That will rotate the focal plane, possibly removing it from your subject, especially with a shallow depth of field.
hollis_f said:And the only difference in that situation is that when you're in 'all points' mode it will display all the focus points that fall on the focal plane. In 'single point' mode the same area will be in focus but the camera doesn't light up the points.
When you use 'all points' the camera will decide what you want to be in focus - and it does that by looking for the closest high-contrast object it can find. Sometimes that'll be the thing you're trying to shoot, often it'll be something totally different. In 'single point' mode it will still pick the closest high-contrast object it can find, but it only looks in a small area (about twice the size of the point's image in the viewfinder. So it's much more likely to choose your desired subject than 'all points'.
One common cause of focus problems is to focus using the centre point, then to recompose by pointing the camera in a different direction. That will rotate the focal plane, possibly removing it from your subject, especially with a shallow depth of field.
On that subject, how would you best track children on the move? Toddlers and babies just never sit still!
hollis_f said:Never tried. I'd be tempted to nail them to the floor, then leave.