Newbie Question on Focusing in Sports Photography

[nelkwan]

Newbie Question on Focusing in Sports Photography

Hi:

I've just started out in sports photography and shot my first soccer game last Sunday. I use the AI Servo mode to auto focus and select the centre focus point to track the subject.

I would like to do recomposition to place the subject off-centre and AI servo would switch focus. How do you use AI Servo focus in such a situation? Is AF focus the only option?

Also, I would like to know if other focus points are able to track using AI servo mode. If it is so, I can at least try to select focus point other than the centre to achieve some form of off-centre composition.

Really want to find out how to take off-centre shots for fast moving subjects.

Please do share any other techiques you use for sport photography! Hope this is not a silly question. cheers!

 

[Reportage]

For fast sports, usually i would use Spot and pre-focus manually where i figure the action will be. Unless the weather is ideal for autofocus, will be losing some shots as the camera looks for contrast to focus on.

 

[Sivakis]

The general rule is:

Besides AI-Servo and One-Shot, there should be one more - AI-Focus. Not sure if that will help.

The other alternative would be to take a further shot with AI-Servo, then crop with recomposition.

 

[Octarine]

Also, I would like to know if other focus points are able to track using AI servo mode. If it is so, I can at least try to select focus point other than the centre to achieve some form of off-centre composition.

It's not described in your camera manual? Never tried out on your own? :dunno:

 

[kongping]

Newbie Question on Focusing in Sports Photography

Hi:

I've just started out in sports photography and shot my first soccer game last Sunday. I use the AI Servo mode to auto focus and select the centre focus point to track the subject.

I would like to do recomposition to place the subject off-centre and AI servo would switch focus. How do you use AI Servo focus in such a situation? Is AF focus the only option?

Also, I would like to know if other focus points are able to track using AI servo mode. If it is so, I can at least try to select focus point other than the centre to achieve some form of off-centre composition.

Really want to find out how to take off-centre shots for fast moving subjects.

Please do share any other techiques you use for sport photography! Hope this is not a silly question. cheers!

The way you describe the auto-focus modes, I suppose you are using Canon SLRs.

As you have described, for action you will usually want to use AI Servo, but yet there are occasions when you want to focus and recompose, i.e. you want the benefits of One-Shot AF.

If so, go to Custom Function 4 and choose either option 1 (or 3). You essentially get AF on demand, i.e. the shutter button only fires the camera / does Auto-exposure but does not AF. AF is performed by the (*) button or the dedicated AF-On / AF button.

For EOS 1-series cameras, with CFn-4-1 the AF-On button defaults to the centre AF point, while with the (*) button you can choose one of the 45 points to AF with. So depending on which button you press you can use the centre AF point or one of the other 45 points to AF with.

If paired with the longer telephoto lenses (300/400/500 2.8/4.0), you may also use the AF stop button. In this instance, no need for you to use CFn-4-1/3.

 

[nelkwan]

Hi KongPing:

Thanks for your helpful reply. I'm using Canon, though not EOS 1-series. For what I gathered, I will work towards two direction in shooting off-centred shots using AI Servo mode.

1) Selecting alternate focus points (other than the middle AF point) and using them to track the subject.
However, based on my research from mags, website etc, it seems that using the middle AF point is the preferred method. Is there a rational for this? What I could think of is that the middle sensor is most sensitive. Hence, people would trust it more than other AF points. Am I write to say so?

2) Using the 'AF on demand' you mentioned.

What I gathered from the manual is:
"2. Metering start/Metering+AF start
This is useful for subjects which keep moving and stopping repeatedly. In the AI Servo AF mode, you can press the <AF-ON> button to start or stop the AI Servo AF operation. The exposure is set at the moment the picture is taken. Thus optimum forcusing and exposure will always be achieved as you wait for the decisive moment."

I'll try to figure out how to best use this method. It'll be good if you share how you use it.

Thanks!

 

[Octarine]

1) Selecting alternate focus points (other than the middle AF point) and using them to track the subject.
However, based on my research from mags, website etc, it seems that using the middle AF point is the preferred method. Is there a rational for this? What I could think of is that the middle sensor is most sensitive. Hence, people would trust it more than other AF points. Am I write to say so?

It's a cross-type focus point. meaning: it can recognize vertical and horizontal lines and contrasts. depending on camera type the other AF sensors might not be cross-types but either horizontal or vertical types. That will limit the ability to determine correct focus. But that also depends on your subject.
More to read: http://en.wikipedia.org/wiki/Autofocus
Again, your manual will tell you whether the other AF points of your camera are cross-types or not.