Tried shooting horses running with 70-200. It kept trying to focus & wouldn't shoot

[spond]

Tried shooting horses running with Canon 6d, lens 70-200.  Pressed shutter half-way, but it kept going in and out trying to focus and wouldn't shoot.  I've taken pics of birds in flight a month ago.  I also had the same problem with my 40mm lens doing the same thing on a still portrait.  I didn't use a tripod on any of t hese shoots.

[spond]

Also, the bird shots were in bright light a month ago & did excellent.  The 40mm was indoors with & without a flash today.  The horses were before dusk 1630 today using both a flash and without.  Could it be the camera?  Settings in all were auto focus.

[cicopo]

Did you set the AF to AI Servo? You need to use AI Servo for moving targets.  It tells the camera to track the moving target & calculate where it should be as the shot is taken.

[cicopo]

Did you set the AF to AI Servo? You need to use AI Servo for moving targets.  It tells the camera to track the moving target & calculate where it should be as the shot is taken.

[jrhoffman75]

You said it works OK in bright light. Sounds like it was too dark and/or not enough contrast for AF to lock on to a subject.

Like cicopo say, you want to use AI SERVO to get sharp images of moving subjects. I don't think AF vs AI SERVO is your problem here, since AF should lock on. It just won't give you a sharp image since subject will have moved by the time the exposure happens.

[ebiggs1]

Without knowing more it is impossible for anybody here to to guess the problem. Ai-servo may have helped but may not have. It isn't a fix all.
A focus issue like this is almost always the camera not getting what it needs. It is up to the photographer to determine what needs attention.
Is this the f2.8 IS version?

[TCampbell]

If you use "One Shot" focus (the default) then the camera uses "focus priority" which means it wont take a shot until it can lock focus.  But since the object is moving, either that will be quite a struggle OR it will get lucky and lock focus, then take the shot -- but the subject will have moved from the focused distance and you end up with an out-of-focus shot.

If you use "AI Servo" mode, the camera uses "release priority" and it WILL take the shot when you fully press the shutter button (and this will happen even if it did not have a chance to focus.)  But the AI Servo mode has a 'predictive' behavior.  It'll acquire focus and not only realize that the focus distance keeps changing, it will notice in which direction the change occurs and will start to keep up with the focus changes.

The 6D doesn't have the advanced focus system capabilities of the 7D II or 5D III.  The center point is the most sensitive and fastest to focus.  But you can't move the camera after it focus or it will re-focus on whatever you moved to.  But you CAN enable a feature called "back button focus" which allows you to push the back button to focus and then release and you'd release when there's a risk that the camera is going to focus on the wrong thing.

On a 7D II or 5D III it's best to let the camera use all available focus points, but this works on those cameras because you get to pick the "initial" point and the camera will follow the subject as it moves around (the focus point will change and keep tracking your subject.)  The 6D doesn't have those advanced modes and since I don't own a 6D I'm probably not the best person to tell you how it will perform if you allow it to use all available focus points when shooting action.

[TTMartin]

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@TCampbell wrote:

If you use "One Shot" focus (the default) then the camera uses "focus priority" which means it wont take a shot until it can lock focus.  But since the object is moving, either that will be quite a struggle OR it will get lucky and lock focus, then take the shot -- but the subject will have moved from the focused distance and you end up with an out-of-focus shot.

If you use "AI Servo" mode, the camera uses "release priority" and it WILL take the shot when you fully press the shutter button (and this will happen even if it did not have a chance to focus.)  But the AI Servo mode has a 'predictive' behavior.  It'll acquire focus and not only realize that the focus distance keeps changing, it will notice in which direction the change occurs and will start to keep up with the focus changes.

The 6D doesn't have the advanced focus system capabilities of the 7D II or 5D III.  The center point is the most sensitive and fastest to focus.  But you can't move the camera after it focus or it will re-focus on whatever you moved to.  But you CAN enable a feature called "back button focus" which allows you to push the back button to focus and then release and you'd release when there's a risk that the camera is going to focus on the wrong thing.

On a 7D II or 5D III it's best to let the camera use all available focus points, but this works on those cameras because you get to pick the "initial" point and the camera will follow the subject as it moves around (the focus point will change and keep tracking your subject.)  The 6D doesn't have those advanced modes and since I don't own a 6D I'm probably not the best person to tell you how it will perform if you allow it to use all available focus points when shooting action.

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On quick thing to add to this. If your using a single AF point centered on the body of a horse there is not a lot of contrast in that area to focus on. So just like with a person, try focusing on the eye/head of the horse. There is more contrast in that area for the camera to pick up on.

[ScottyP]

I agree with everyone on the AI Servo mode for the moving horses. 

What at kind of camera is this?  Rebels will have difficulty auto focusing in dim light, which can be very frustrating, and what is dim to the camera is not really all that dim to the human eye at all. 

Also:  

1.) Forget the flash.  The shutter speed you need to freeze a running horse is above the max flash sync speed, so your flash will be in HSS mode with diminished output/range, and the distance of a running horse in any scenario I can imagine puts the subject too far away for flash to really do much.   Especially if we are talking about the built-in flash.  Maybe if you had off camera flash on light stands right close to where Mr. Ed would run by it or something...

2.) Use the focus limiter switch on the 70-200 (if yours has one).  Set it to only focus at longer distance things. That way it has less freedom to hunt all over the place wildly if it loses focus. 

3.) Shoot before dusk if possible.  Everything in photography, including autofocus, is easier when there is plenty of light.  

[ebiggs1]

"Maybe if you had off camera flash on light stands right close to where Mr. Ed would run by it or something..."

I have set up dual flashes in the corners of a gymnasium and flashed the Seniors walking across the stage on the other end. This just depends on what flash you are using.  The one that comes on a Rebel or even the 7D Mk II is a joke.  Canon must be snickering under their breath over that one!

"Everything in photography, including autofocus, is easier when there is plenty of light."

Amen to that! Amen.