Looking for tips on focusing for moving subjects

I am having trouble with focusing moving subjects. Mostly for me that is dogs, horses, birds and the like. I am using shutter speed of 1/500 and in TV mode. I am using auto focus as I can't manually focus fast enough - still finding many shots not in focus. The AF mode I am using is Al Focus AF. I would be grateful for any tips. Usually using ISO of 100 or 200. In dimmer light, I have set ISO on auto. Those are often pretty noisy.

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Permalink Reply by marcus.scheer on June 17, 2011 at 1:38pm

I would probably move your AF mode to AI Servo -- and then check your AF Point. I would brush up on your camera's manual (it provides you with a few details). AI Servo should continue to focus on your subject the whole time. Try to start with your subject in the middle of your frame (if your AF Point is the center) and press your shutter button halfway. Even if your subject moves from the center, your camera *should* maintain focus on it.

If you are feeling ambitious, I'd even try back-button focusing. (Once you get used to it, you may never go back.) Basically, it removes the focusing part away from the shutter button and onto a different button. You don't have to worry about your camera not taking a picture because it is trying to focus! If you want to know more about it, let me know!

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Permalink Reply by Charlotte Louise on June 17, 2011 at 4:10pm

My AF point is in the center... I have checked my manual.

I would like to know more. What is back button focusing?

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Permalink Reply by CameraClicker on June 17, 2011 at 5:26pm

"back button focusing" is assigning a button on the back of the camera, where the thumb of your right hand rests, to use as the focus button, instead of using the shutter release. Then when you want the camera to focus you press the button you assigned.

Can we see a sample problem shot?

The book for my T2i says AI Focus AF switches the AF mode from One-Shot AF to AI Servo AF automatically if the still subject starts moving. Once in AI Servo mode, the focus confirmation light will not light, but it might beep. You have to keep the focus point on the moving subject. This makes it sound like AI Focus is a good choice.

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Permalink Reply by Charlotte Louise on June 17, 2011 at 10:44pm

So here the sharpest area is the hind end of the dog. Not ideal. :-(

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Permalink Reply by CameraClicker on June 18, 2011 at 5:00am

The resized image does not show the AF points. The centre AF point is on the grass in this image. For this sort of shot, where you know almost exactly where the dog will be, you can pre-focus then release the shutter when the dog arrives. I applied sharpening to the image and all of it looks reasonably focused. At this size, I don't see the hind end as having better focus.

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Permalink Reply by Craig Ruhl on June 17, 2011 at 7:05pm

I am just an amateur when it comes to actions shots. The shots that have been successful for me have been where I have my Canon Xti set on AI Servo, center weighted metering and a fast shutter speed. I have shot birds in sports mode, but prefer to shoot in Tv (shutter priority) with a speed of about 1/1500 to 1/2500. I will adjust F stop depending on available light. My technique is to use manual focus, watch the pattern of subject movement for a bit to get a feel for distance and location. Then I manually focus the lens on the spot where I anticipate the subject to be when I take the shot. After that I wait until a subject enters the "shot" zone. From there, small adjustments in focus can be made. Obviously, I take a lot of shots that don't work out, but that is the beauty of digital. I do use also multiple shot mode and keep the shutter held down as I lead the subject a bit. Like I said, I am not pro on this subject so hopefully others who know better will help out.

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Permalink Reply by marcus.scheer on June 18, 2011 at 9:53am

If you want a more detailed version on back-button focusing, here is a link to an article directly on Canon's site. http://www.learn.usa.canon.com/resources/articles/2011/backbutton_a...

As far as getting the 'fast movement effect,' basically you use a slow enough shutter speed to blur the background and you physically pan the camera to follow your subject -- allowing for it to stay in focus. (And I imagine there are plenty of other people here who can explain this better than I just did!)

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Permalink Reply by Charlotte Louise on June 19, 2011 at 11:39am

Thanks everyone. I am going out to practice more today on this issue keeping your tips in mind.

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Permalink Reply by Anne Brooks on July 1, 2011 at 7:16pm

So, how would I do this on the Nikon d90? If I set it on continuous, the focus changes to something else than my subject. How do I keep it on the subject and recompose? Thanks.

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Permalink Reply by Bill Perry on July 8, 2011 at 1:10pm

Move the switch from "C" to "S" mode on front of camera and focus will stay locked while re-composing shot as long as the shutter release is held 1/2 way down.

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Permalink Reply by mike whatley on July 9, 2011 at 4:35am

I usually use a much higher shutter speed (1500-2500) in the TV mode and Al Servo for outdoor sports action shots. Try a free program called "Noiseware Community Edition" to reduce any noise you are getting.