7D AF tracking accuracy - accidental test

For the naysayers and the ones that still can't decide on leaving the xxD series for 7D I want to give you an idea how 7D performs with moving subjects.

I want to state that this was not intended to be a test from the begining but after seeing how well camera kept focus on the flying eagle, even though it flew behind the tree, I figured I will share the results.

I was taking the burst of shots and when I saw the eagle behind the tree I stopped shooting. Now I regret that I didn't continue taking more pictures to see when the camera will eventually fail to focus.

Following shots are a downsized full frames (not cropped, only resized for the web). Please note that eagle isn't on the center of the frame (my fault) but camera kept focus anyway - this is where the extra focusing points of 7D come handy

Shots were taken with 400mm f/5.6 lens, using the AI Servo mode, 8fps, center AF Point Expansion with following C. Fn. III settings:
1 - one stop before SLOW setting
2 - 0
3 - 0
4 - 1

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Thanks for posting a real world example.

Not bad.

I did something similar the other day with a car that drove behind a guy on the sidewalk and then behind some bushes. The camera tracked it the entire way--very cool. My settings were similar to the original posters.

Wow... that's terrific!

love it this camera impresses me every day

Very impressive. I love my 7D!

Excellent post, and very encouraging....just need to get Xmas outta the way and I can put some pennies away for a 7D in 2010!

In this kind of situations having the ability to adjust the sensitivity of the AF is priceless...

Thanks for posting.

A good example of using the sloweer tracking speed. I have felt nervous using that, but your pics show it is the right answer.

I wonder about the C.Fn III-3 setting at 0 (Main focus point priority). GIven what it says in the manual, I would have had it on 1 (Continuous AF track priority). With the setting at 0, the main focus point should have started focus on the trees rather than the bird. Perhaps it was the slower tracking speed that save the shot. Personally, I have found very hard to track fast moving BIFs with any tracking speed slower than the middle level.

That's a pretty impressive test. I'm amazed that the focus kept tracking.

cfibanez wrote in post #9176733
Personally, I have found very hard to track fast moving BIFs with any tracking speed slower than the middle level.

It's not the tracking speed you set, it's the delay before it starts hunting for something else, if it looses focus. From 1 second at the slowest to 0.125 seconds at the fastest, if it uses the same timing as the 1D Mark IIn. I've not seen any data for the 7D.

In the example above, it could be that the branches in front of the bird were so far out of focus that the AF sensor didn't even see them.

cfibanez wrote in post #9176733
I wonder about the C.Fn III-3 setting at 0 (Main focus point priority). GIven what it says in the manual, I would have had it on 1 (Continuous AF track priority). With the setting at 0, the main focus point should have started focus on the trees rather than the bird. Perhaps it was the slower tracking speed that save the shot. Personally, I have found very hard to track fast moving BIFs with any tracking speed slower than the middle level.

That's correct. Slower tracking=>sensitivity is what saved these shots and that is exactly what it should do when another object "enters the frame". The extra AF points helped when the bird moved out of the center of the frame (center focusing point).

Thanks for sharing
I'm surprise how well it did with the branches in the way.