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Archive 2014 · Can someone help me with AI Servo? Moving subject issues.

  
 
Lightlightlight
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p.1 #1 · p.1 #1 · Can someone help me with AI Servo? Moving subject issues.


I have been trying to use AI servo for moving subjects with very little success. In fact I don't think it's even turning on. I've read the manual 5D3. I've watched videos. I'm stumped. Should I not see the focus point track a subject as I keep holding down back button AF?

My goal is to improve moving subject photographs. I can't see to get high keeper rates with even walking subjects. Even when I'm 1/250th or high I am getting maybe 20% keeper rates using one shot.

Thank you



Oct 05, 2014 at 05:43 AM
dgdg
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p.1 #2 · p.1 #2 · Can someone help me with AI Servo? Moving subject issues.


Make sure back button is set to focusing and keep it pressed.
Set your active focus points to all available. Then the initial focus point will be the center point unless you defined it as somewhere else. As you move the camera or subject you should see the active points move around.



Oct 05, 2014 at 06:00 AM
jcolwell
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p.1 #3 · p.1 #3 · Can someone help me with AI Servo? Moving subject issues.


There's two issues: (i) tracking subject motion with respect to your location, and (ii) tracking the subject as it moves across the focus points on your finder. As David mentioned, you first need to acquire AF lock, usually with the centre AF point, and then track the subject while AI Servo AF is still activated. I also use the back button for AF, but it works find with a half-press of the shutter button, if that's your preference.

I generally track moving subjects with only the center AF point, and a few AF Expansion "helper AF points" active. If I can't keep the subject more-or-less centred, then I lose track. That's my preference. You might prefer to have all AF points active, but you still have to achieve initial AF lock and keep AF active the whole time that you're tracking the subject, or re-acquire AF lock if AF has "spun down".

Also, you can have problems if you're using an IS lens to track a subject while IS is in Mode 1 (and in some cases, in Mode 2).



Oct 05, 2014 at 06:08 AM
dgdg
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p.1 #4 · p.1 #4 · Can someone help me with AI Servo? Moving subject issues.


Certainly good advice Jim, a well experienced bif photographer.

I was trying to think of the easiest setup for the OP to prove ai-servo tracking was working. Sounds like a settings issue. I assume ai-servo is on. With low keeper rate, some focus tips are in order too.



Oct 05, 2014 at 07:54 AM
rolette
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p.1 #5 · p.1 #5 · Can someone help me with AI Servo? Moving subject issues.


Simple test to see if it is working...

Get a volunteer to stand well away / across the room from you. Focus on them in AI Servo mode and keep AF active (half-press shutter button or using back-button focus). Have them walk towards you slowly.

You'll hear the lens make AF adjustments as they move toward you if it is working.

Jay



Oct 05, 2014 at 08:02 AM
EB-1
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p.1 #6 · p.1 #6 · Can someone help me with AI Servo? Moving subject issues.


Which lens are you using? I'm inclined to suspect a settings issue, as the 5D III has a good AF system, even for off-center points.

EBH



Oct 05, 2014 at 08:44 AM
dwweiche
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p.1 #7 · p.1 #7 · Can someone help me with AI Servo? Moving subject issues.


Lightlightlight wrote:
...
My goal is to improve moving subject photographs. I can't see to get high keeper rates with even walking subjects. Even when I'm 1/250th or high I am getting maybe 20% keeper rates using one shot.

Thank you


Eliminate the possibility of blur due to subject movement. 1/250 on moving subjects is an issue. Fix your shutter speed at 1/1000 and then you can be more confident if focus is your real issue.



Oct 05, 2014 at 10:08 AM
Gochugogi
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p.1 #8 · p.1 #8 · Can someone help me with AI Servo? Moving subject issues.


Lightlightlight wrote:
I have been trying to use AI servo for moving subjects with very little success. In fact I don't think it's even turning on. I've read the manual 5D3. I've watched videos. I'm stumped. Should I not see the focus point track a subject as I keep holding down back button AF?

My goal is to improve moving subject photographs. I can't see to get high keeper rates with even walking subjects. Even when I'm 1/250th or high I am getting maybe 20% keeper rates using one shot.

Thank you


Besides enabling AI Servo, you should use continuous high speed shooting mode. One-shot will have a very low keeper rate since, well, you only get one shot. With a short bust I normally get a few keepers along with a few missed frames, and often the first one frame isn't the good one.



Oct 05, 2014 at 11:48 AM
jcolwell
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p.1 #9 · p.1 #9 · Can someone help me with AI Servo? Moving subject issues.


+1


Oct 05, 2014 at 02:36 PM
gdanmitchell
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p.1 #10 · p.1 #10 · Can someone help me with AI Servo? Moving subject issues.


Just a real basic point that some folks overlook: AI Servo is a "predictive" focus mode. It not only attempts to find an AF point (sort of) but it also attempts to make an intelligent guess as to the actual focus point at the time of exposure, when the subject will not be in the same position it was in when focus was determined.


Oct 05, 2014 at 03:01 PM
jcolwell
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p.1 #11 · p.1 #11 · Can someone help me with AI Servo? Moving subject issues.


gdanmitchell wrote:
Just a real basic point that some folks overlook: AI Servo is a "predictive" focus mode. It not only attempts to find an AF point (sort of) but it also attempts to make an intelligent guess as to the actual focus point at the time of exposure, when the subject will not be in the same position it was in when focus was determined.


With continuous shooting in AI Servo AF mode, the camera actually calculates the relative velocity of convergence or divergence between the subject and camera, and so calculates where the subject will most likely be located when the shutter goes off. That's better than an "intelligent guess". As Peter K.F. hints when he mentions that it should be in continuous shooting mode, the camera can't do this reliably in One Shot AF mode, because it doesn't know when you'll push the shutter button.



Oct 05, 2014 at 03:14 PM
gdanmitchell
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p.1 #12 · p.1 #12 · Can someone help me with AI Servo? Moving subject issues.


jcolwell wrote:
With continuous shooting in AI Servo AF mode, the camera actually calculates the relative velocity of convergence or divergence between the subject and camera, and so calculates where the subject will most likely be located when the shutter goes off. That's better than an "intelligent guess". As Peter K.F. hints when he mentions that it should be in continuous shooting mode, the camera can't do this reliably in One Shot AF mode, because it doesn't know when you'll push the shutter button.


Well, semantics aside ("intelligent guess"), we are saying the same thing, aren't we? ;-)

(In my view, cameras with multiple AF points must "guess intelligently," since they cannot, for example, "know" the relative importance of the different points to the photographer. However, I'm happy to instead say that the camera uses algorithms which determine the focus setting for the lens based on multiple AF point data and predictions about the likely location of a moving subject.)

Dan



Oct 05, 2014 at 10:07 PM
onesickpuppy
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p.1 #13 · p.1 #13 · Can someone help me with AI Servo? Moving subject issues.


I would say....we need to see some samples...with data intact

Too much vague descriptions....assumptions of target....etc etc.

I have the 5D3 as well...and at times it does have issues with tracking...but there are reasons:
1. no contrast on subject
2. bad technique
3. settings (shutter speed/f stop)
4. what lens are you using (and I got less keepers on the newer version II's long glass on fast moving targets at times)

so...please post a few samples showing settings..and let us have a better idea of what we're guessing at



Oct 06, 2014 at 01:42 AM
Ferrophot
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p.1 #14 · p.1 #14 · Can someone help me with AI Servo? Moving subject issues.


I second the suggestion that 1/250th is too slow for a moving subject. 1/1000th or more is needed. Another suggestion is to give the AF some latitude, so choose a higher f stop as well. Something like 1/1600th at f 6.3 or 8. If that improves things you can come on down with both settings as you get more practice and experience.


Oct 06, 2014 at 02:01 AM
Lightlightlight
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p.1 #15 · p.1 #15 · Can someone help me with AI Servo? Moving subject issues.


Thanks everyone for the replies. I have taken all the suggestions to heart and will utilize all of the suggestions offered. I am grateful. As for posting samples, I have never had AI Servo work. I am still as of today missing a setting somewhere as the camera says I'm in servo, but I do not see tracking. I see the same thing as one shot and have to manually move my point. I am stumped. I've read the manual, went through every function in the menu and I'm not finding the setting that's keeping it off. I'm going to look into this more in the next few days.


Oct 06, 2014 at 02:49 AM
Deborah Kolt
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p.1 #16 · p.1 #16 · Can someone help me with AI Servo? Moving subject issues.


At 1/250 of a second, you're going to get so much motion blur you won't see anything. The minimum shutter speed to stop motion is 1/500 and at that you're sometimes going to see some blur in hands or feet. If they're running, your best bet is 1/1000 and above. In football, for example, I try for a minimum of 1/2000 if the light is adequate, so it is tack sharp.

Sounds like the problem is your settings, not the AI Servo. Put your camera in AV, open your aperture as wide as it will go, and see if you've got enough light to get you to 1/1000. (if you don't have a grey card to meter, you can use the grass. It's close to 18%.) If not, bump up your ISO and check again. Repeat until you do. Then test your camera again. And remember, you won't see the focal point indicator move when it's tracking.

You might try reading over in the Sports Corner for more hints.



Oct 06, 2014 at 01:10 PM
ccho
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p.1 #17 · p.1 #17 · Can someone help me with AI Servo? Moving subject issues.


Lightlightlight wrote:
Thanks everyone for the replies. I have taken all the suggestions to heart and will utilize all of the suggestions offered. I am grateful. As for posting samples, I have never had AI Servo work. I am still as of today missing a setting somewhere as the camera says I'm in servo, but I do not see tracking. I see the same thing as one shot and have to manually move my point. I am stumped. I've read the manual, went through every function in the menu and I'm not finding the setting that's keeping it off. I'm going to
...Show more

I think most of these answers are great, but none of them addressed your question about a visual display of the tracking. The 5Dmk3 does not provide this, nor does any Canon DSLR to my knowledge. What you are selecting in AI Servo is the initial focus target so when you initiate the autofocus, it will attempt to lock focus on the object that is on that select focus point. If you hold down the focus button, it will continue to try to track the object even if it has moved within the frame. There is currently no visual indicator showing where the camera believes the object to be in your frame. Perhaps what you were thinking was something similar to face tracking available in which a visual indicator is displayed on a live view screen that a camera such as the EOS M features.

Hope this clears up your confusion.



Oct 06, 2014 at 05:56 PM
gdanmitchell
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p.1 #18 · p.1 #18 · Can someone help me with AI Servo? Moving subject issues.


ccho wrote:
I think most of these answers are great, but none of them addressed your question about a visual display of the tracking. The 5Dmk3 does not provide this, nor does any Canon DSLR to my knowledge. What you are selecting in AI Servo is the initial focus target so when you initiate the autofocus, it will attempt to lock focus on the object that is on that select focus point. If you hold down the focus button, it will continue to try to track the object even if it has moved within the frame. There is currently no visual indicator
...Show more

Jeez, you are right! I meant to "way back" in this thread, but then got sidetracked reading other replies and figured that someone must have already pointed out that you don't get AF confirmation lights (at least not on my Canon DSLR) in AI Servo mode.

I recall that this confused me at first, too!

Dan



Oct 06, 2014 at 06:52 PM
PetKal
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p.1 #19 · p.1 #19 · Can someone help me with AI Servo? Moving subject issues.


gdanmitchell wrote:
Jeez, you are right! I meant to "way back" in this thread, but then got sidetracked reading other replies and figured that someone must have already pointed out that you don't get AF confirmation lights (at least not on my Canon DSLR) in AI Servo mode.

I recall that this confused me at first, too!

Dan


The old 1D cameras flash a red alert LED in VF when Servo AF gets derailed (i.e., no AF). That is your Servo AF confirmation. No fast red LED flash means Servo AF is locked onto something, not necessarily the intended target.

New cameras like 1DX with their advanced VF display screens do Servo AF display differently . When the camera does a multipoint AF auto selection, be it zone AF or full frame AF, the AF points which attain focus are displayed in VF "on line". That feature I like. What I do not like is poor visibility of the display points, whether they are flashing, changing colour or what not.



Oct 06, 2014 at 07:28 PM
gdanmitchell
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p.1 #20 · p.1 #20 · Can someone help me with AI Servo? Moving subject issues.


I'd be happy to see _some_ confirmation on the 5D2, but I've learned to deal... ;-)

Dan



Oct 06, 2014 at 07:29 PM
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