Improving AI Servo Hit Rate on the 7D

Just a query of suggestions/tips from other 7D users of various things to try to improve the AI servo hit rate on my 7D...

Lately I've been messing around with my dog playing in the snow and I'm just noticing i get a lot of "misses" for every good shot or two, Now shes not exactly a puppy anymore (Shes almost 14 years old, And not a small tiny dog mind) so despite her running and that, She's not exactly that fast

So far I havnt delved much into the C.Fn menus and tried adjusting any of it, But I have tried the different AF point modes, Single point or 19pt is getting the best results I think (I plan to try AF Point Expansion a second time, The first time it was focusing on either her nose or her back leaving her face out of focus 90% of the time..Which i thought was weird...I didnt have the BEST light that day however, So that MIGHT have been the issue)

From my observations, It appears the AF system is getting overzealous and locking on to a different part of her when she moves slightly instead of "grabbing" and holding on where i tell it to start focus (I mean look, im moving the camera, adjusting the focal length and etc)

My next outing with her (Tomarrow, as its too dark now to get good shutter speeds) I'm planning to try out the following combination:

-Having Cfn III 1(AI Servo Tracking Sensitivity) set to -1 and Cfn III 3(AI Servo AF Tracking Method) set to 1 (Continuous AF Track Priority)

-AF Point Expansion

And for the record im trying to not let the shutter speed dip below 1/800(Average is 1/1200+ Thats definitely not in the realm of dragging the shutter in my book), and im using the 70-200 f/4L IS and IS Mode 2 and YES im letting the IS spin up (I DO know what I'm doing fellas, Just not so used to shooting action like this..) And yes I'm using the AF-ON to start AF

I of course, might just be expecting a little more than the 7D can do, But I dont think so, and I am getting some keepers mind, I'm just trying to increase the keeper rate

Give me a few moments to pull up some relevant examples from today...

I would set the af to tracking priority and set the af tracking speed (I forgot what it is called) to slow or slowest (one or two from the middle respectively) and see if this calms the 7D from trying to track every little thing.

Here are my settings, for what it's worth, although I do very little AI Servo action shooting. These are loosely based on reading various recommendations here and elsewhere, and are consistent with what themadman recommends above.
C.FNIII:Autofocus/Driv​e
1 AI Servo tracking sensitivity - Slow (one or two marks to left of center - I have mine all the way to the left) - purpose: decreases chance focus will shift from original subject due to something like an intervening object during subject movement by increasing time before system tries to achieve focus on something new in scene
2 AI Servo 1st/2nd img priority - 0:AF priority/Tracking priority - purpose: puts priority on achieving focus and keeping focus during tracking
3 AI Servo AF tracking method - 1:Continuous AF track priority - purpose: puts priority on maintaining continuous tracking focus rather than maintaining focus at main focus point

I think what you're planning to do tomorrow should help. From what I've read, the best approach for tracking something moving on the ground would probably either be zone or single point with expansion, because the 19 points might be more likely to shift focus off to something else in the scene (unless shooting something like birds in flight where the "scene" is a blank sky). From what you're saying, however, it seems it's worked OK for you.

I like your attitude. Rather than blaming the camera you are trying to figure it out. I wish more people would have that attitude. I will keep track of this thread because I have same results. I'm sure we'll figure it out. Sorry I'm not much help.

stsva wrote in post #13745144
Here are my settings, for what it's worth, although I do very little AI Servo action shooting. These are loosely based on reading various recommendations here and elsewhere, and are consistent with what themadman recommends above.
C.FNIII:Autofocus/Driv​e
1 AI Servo tracking sensitivity - Slow (one or two marks to left of center - I have mine all the way to the left) - purpose: decreases chance focus will shift from original subject due to something like an intervening object during subject movement by increasing time before system tries to achieve focus on something new in scene
2 AI Servo 1st/2nd img priority - 0:AF priority/Tracking priority - purpose: puts priority on achieving focus and keeping focus during tracking
3 AI Servo AF tracking method - 1:Continuous AF track priority - purpose: puts priority on maintaining continuous tracking focus rather than maintaining focus at main focus point

I think what you're planning to do tomorrow should help.

Glad you agree, these are the settings i basically have (Except for it only being one mark to the left)

Also i will add on inspection -on my computer- i did get quite a lot more in-focus shots than i thought from looking at the rear screen to judge focus, Including a bunch i did at dusk where my shutter speed WAS dragging a bit for what i was trying to do (I was up at ISO3200, f/4, and 1/320 at best) More of those were wrecked by the crappy shutter speed than being out of focus...

Northontguy wrote in post #13745151
I like your attitude. Rather than blaming the camera you are trying to figure it out. I wish more people would have that attitude. I will keep track of this thread because I have same results. I'm sure we'll figure it out. Sorry I'm not much help.

Well im confident that the 7D can do this, I have had my 7D for 3 years now and while i've had my disagreements with the AF system from time to time, overall i find it works marvelously about 99% of the time... I just figured that theres probubly just some tweaking in the C.Fn that can be done to improve everything

Read this, and you will understand that your cameras AF is not magic. Particularly the last few paragraphs.
http://groups.google.c​om …sg/1d08cffa5aac​26b6?pli=1

That link talks about a 10-year old film body...

FlyingPhotog wrote in post #13745315
That link talks about a 10-year old film body...

More than 10, in the first paragraph it states it was written for the Original EOS-1, Which was more like 20-something years ago...

Looking over the photos from today im noting that i think my rear screen was giving me a false sense of "Wow the AF is really blowing it a lot"

FlyingPhotog wrote in post #13745315
That link talks about a 10-year old film body...

Maybe so. But I am yet to hear about an AF system that can read a live subjects mind.

It sounds like the 7D has the same AF settings, or very close, to my MKIII.

After a lot of experimenting, here is where I ended up.

Center point only. High speed, center point only, assist points on, focus priority.

During motion, I have the AF running all the time with a half button press and fire when I want.

That seems to get me better results, but which I mean more keepers.

I do not know if that approach will work with the 7D.

At least for me, slowing down the AF response speed was a bad idea. It meant missing shots. Now, I found that after I went to focus priority vs, drive priority. I went to focus priority to avoid shooting a bunch of OOF shots.

Your path and mileage may vary.

speedync wrote in post #13745381
Maybe so. But I am yet to hear about an AF system that can read a live subjects mind.

Yes, And need i restate, im not new to this, this isnt my first go-round, I understand the limitations of AF systems, i understand the 7D has its limitations and barriers and its not perfect

All i am merely trying to do is push it to those barriers and make sure im wringing every single inch of performance i can out of it, And there is nothing wrong with that...Yeesh

ANYWAYS heres a series from the 7D....I posted the first one above..but decided after review that i should show the next few images, this is before ANY processing, No sharpening or anything has been applied

Grey Dog in flat light...

I bet you'd get better results in more contrasty conditions.

FlyingPhotog wrote in post #13745492
Grey Dog in flat light...

I bet you'd get better results in more contrasty conditions.

Probubly, But hey, Work with what I've got at the moment

And are the results -that- bad taking that into account?