What is the best AF mode for shooting AI Servo?

I have only had my 7d for a relatively short period of time and as such, I am still learning to master all of its functions.

Last weekend I shot a heap of test shots at the Red Bull Air race which was held here in Perth Western Australia.

I had the camera set to high speed continuous shooting with the AF to set either Manual AF point or AF point expansion in AI servo mode.

At the end of the day I was a little bit disappointed with the final results. I am not sure if it was the camera not fully locking onto the subject properly or if I was not panning quickly enough to keep the plane locked into my focus points. (The planes were moving pretty damn quick through the course)

I am just curious what settings everyone else is using for high speed sports.

I'm using these:

Exposure Mode: Tv
ISO: Auto
Shutter speed: 1/1600 (to start with)
Av: N/A
White Balance: Auto
Metering Mode: Evaluative
AF Mode: AI Servo
AF Area: Point Expansion (center point)
Drive Mode: High Speed Continuous
Picture Style: Standard 3,0,0,0 (for when I shoot jpeg)

Fn I-6 (Safety Shift): 1 - Enable
Fn III-1 (AI Servo tracking sensitivity): Between slow and middle/0
Fn III-3 (AI Servo AF tracking method): 1 - Continuous AF track priority

doofuss wrote in post #10029341
I have only had my 7d for a relatively short period of time and as such, I am still learning to master all of its functions.

Last weekend I shot a heap of test shots at the Red Bull Air race which was held here in Perth Western Australia.

I had the camera set to high speed continuous shooting with the AF to set either Manual AF point or AF point expansion in AI servo mode.

At the end of the day I was a little bit disappointed with the final results. I am not sure if it was the camera not fully locking onto the subject properly or if I was not panning quickly enough to keep the plane locked into my focus points. (The planes were moving pretty damn quick through the course)

I am just curious what settings everyone else is using for high speed sports.

My basic rule: If the subject covers a substantial amount of your VF e.g 35-50% +, use AF point expansion. This way the assist points do help. If less than 50%, I use single point AF. In NO WAY use Spot AF (too slow...!)
Also remember to put C.FNIII, 3 to 0: Main focus point priority (default) so that the main focus point point has priority over the assist / expanded points.

For propeller Aircraft, you need to go down on shutter speed to capture propeller motion.. 1/200 - 1/500 is OK. But good panning is a must.

A few shots from the same race (Red Bull)in Abu Dhabi a few weeks back....

Hope that helps...

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Another thing to keep in mind is that if you don't use evalutive or spot metering, you need to start AI Servo with center AF point only to improve the accuracy of exposure. There is a slight delay at the beginning of tracking so don't press shutter right away.

This is not right. The 7D is able to start tracking from any of its 19 cross-type AF points. Where is this info coming from ?.

dchen99 wrote in post #10029984
Another thing to keep in mind is that if you don't use evalutive or spot metering, you need to start AI Servo with center AF point only.

If you set C.Fn III-3 to 0, the 7D will switch focus to the other plane that passes and covers your main target plane. So in general you don't want to do that.

smv81147 wrote in post #10029856
My basic rule: If the subject covers a substantial amount of your VF e.g 35-50% +, use AF point expansion. This way the assist points do help. If less than 50%, I use single point AF. In NO WAY use Spot AF (too slow...!)
Also remember to put C.FNIII, 3 to 0: Main focus point priority (default) so that the main focus point point has priority over the assist / expanded points.

For propeller Aircraft, you need to go down on shutter speed to capture propeller motion.. 1/200 - 1/500 is OK. But good panning is a must.

A few shots from the same race (Red Bull)in Abu Dhabi a few weeks back....

Hope that helps...

maverick678 wrote in post #10030119
If you set C.Fn III-3 to 0, the 7D will switch focus to the other plane that passes and covers your main target plane. So in general you don't want to do that.

No, I believe this is not correct. What you are referring to may be CFnIII 1: AI servo tracking sensitivity that must be set to -1 or -2 (slow).

I believe CFn III 3: AI servo AF tracking method refers to which AF point has priority in AF expansion mode. Main/Center if set to 0, or periferal / assist if set to 1 (Continuous).

In any case I was shooting single moving objects (airplanes) so there is no interference. But if the subject does not cover the Main focus points AND its assist points (ie. small subject in VF) then the assist points may focus in the background and if in priority mode, the image will be OOF. I believe that if in Main Focus priority the main point is in control....

I trust this is correct...

You've misunderstood the custom functions. I'm not referring to C.Fn III-1, that's basically that how fast the camera will switch to a different focus point (if it's available). I'm referring to C.Fn III-3, this is the setting to tell the 7D to switch to different focus point (if it's available) or ignore it. It usually means the new object that's passing/covering is closer/nearer to your 7D than your original focusing object.

Check out Video #6.

http://www.usa.canon.c​om …ctID=329&articl​eTypeID=48

smv81147 wrote in post #10030210
No, I believe this is not correct. What you are referring to may be CFnIII 1: AI servo tracking sensitivity that must be set to -1 or -2 (slow).

I believe CFn III 3: AI servo AF tracking method refers to which AF point has priority in AF expansion mode. Main/Center if set to 0, or periferal / assist if set to 1 (Continuous).

In any case I was shooting single moving objects (airplanes) so there is no interference. But if the subject does not cover the Main focus points AND its assist points (ie. small subject in VF) then the assist points may focus in the background and if in priority mode, the image will be OOF. I believe that if in Main Focus priority the main point is in control....

I trust this is correct...

maverick678 wrote in post #10030011
This is not right. The 7D is able to start tracking from any of its 19 cross-type AF points. Where is this info coming from ?.

Stand corrected.
Edited my post to reflect that's the purpose for better exposure metering. Nothing to do with focus.

maverick678 wrote in post #10030372
You've misunderstood the custom functions. I'm not referring to C.Fn III-1, that's basically that how fast the camera will switch to a different focus point (if it's available). I'm referring to C.Fn III-3, this is the setting to tell the 7D to switch to different focus point (if it's available) or ignore it. It usually means the new object that's passing/covering is closer/nearer to your 7D than your original focusing object.

Check out Video #6.

http://www.usa.canon.c​om …ctID=329&articl​eTypeID=48

True, I misunderstood CFn I. But as far as CFn III-3 believe we're both right. What stands for passing/covering in front, may also be applicable for what is behind (background). I am shooting single subject action ie. a tennis player or an airplane (no front interference). I experienced that I loose focus towards the background subjects if set to "continuous". If set to "main" I keep focused, unless my panning is erratic and the main focus point hits the background. The opposite may hold true for multi subject action ie. football / basketball players, where front interference of the main subject may be avoided if in "continous" mode... Just a thought...

From the manual:

------
C.Fn III - 3 AI Servo tracking method
In the AI Servo AF mode while you are focus-tracking a subject, the camera can either continue focusing the target subject - even if a closer subject (closer than the main focus point) suddenly appears in the picture, or the camera can switch to focus the closer subject.

0: Main Focus Point Priority
The active AF point will switch to the main focus point and start focusing the closer subject. Convenient when you always want to focus the closest subject.

1: Continuos AF track priority
Any closer subject appearing in the picture will be ignored as an obstruction. The main focus point does not take priority, so the tracking of the target subject can continue and switch to an adjacent AF point based on the preceding focusing result. Convenient when obstacles such as telephone poles go in front of the target subject.
---------

As mentioned in my first post in this thread - I prefer this set C.FN III-3 to "1" - if I'm tracking a subject (Bird, skater, cyclist, etc) I don't want passing/in-between objects to take my focus away from the subject.

Setting C.Fn III-1 to slow and C.Fn III-3 to 0 is kind of pulling in the opposite direction. Your telling the camera to try to focus on the closest subject as soon as it comes into an active focus point (C.Fn III-3) and then telling the camera to take it's own sweet time refocusing (C.Fn III-1)....

It would seem that these two functions (C.Fn III-1 and C.Fn III-3) would best be used in tandem as follows:

C.Fn III-1 set to fast +2 and C.Fn III-3 set to 0. This would let your camera decide to switch to whatever was closest to you and quickly refocus to whatever your focus point is on top of. Probably best used in this combo when you're not tracking a specific subject and you want to jump around from target to target.

C.Fn III-1 set to slow and C. Fn III-3 set to 1. This would force your camera to try and stay on the subject you are following and would stop the camera from attempting to acquire closer/interim subjects that move in front of your subject/target. It would also slow down attempts to refocus on new subjects.

I typically use the latter in tandem because I'm tracking a specific subject (my daughters).

Examples
- Skiing: My Daughter is skiing down a slope - there are other skiers. I am looking to just photograph my daughter and not other skiers that are closer to me and sometimes enter into my shot.
- Skating: On a crowded rink, people constantly skate into my shot as I track my daughter. So I like to set my camera to ignore other subjects and stay focused on my daughter.

I could imagine using the first tandem in a situation like the Boston Marathon yesterday. A lot of runners coming at me and I want to hop from subject to subject coming straight at me - this would allow my focus point to quickly jump to my new subject and then quickly refocus.

These features are one of the reasons why I upgraded from my T1i... That camera made a lot of decisions for me when I was following subjects. The most annoying was the constant attempt to refocus on subjects that fell in between me and the target/subject.

doofuss wrote in post #10029341
I am just curious what settings everyone else is using for high speed sports.

1DMK2N ........

Enjoy your 7D

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I really do, Thnx!

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lumpydog...good info. I will use my 7D to photograph my daughter playing volleyball. Typically, when shooting from the other side of the net, the net will become the autofocus point (on my 40D). Will your 'later' option help with this if I start the tracking on my daughter 1st?