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One of our readers, Rachel, left a comment on the Nail your Autofocus tutorial from a few weeks back. She wanted advice on photographing busy kids and particularly mentioned Nikon’s 3D tracking and continuous servo.

But there’s more to photographing moving subjects than that. So let’s look at achieving focus in fast moving situations. If you want to photograph sports that involve fast movement, including your kids’ sports, or your young children playing, this tutorial on how to focus on fast moving subjects is absolutely for you.

We’ll go into greater detail on autofocus settings, specifically:

  1. Continuous autofocus
  2. Autofocus area modes
  3. Focus tracking duration
  4. Back button focus
  5. Vibration reduction / Image stabilisation

But first, here’s Rachel’s questions on how to focus on fast moving subjects….

1. Does every Nikon model do 3d tracking?

2. You mentioned that you use continuous servo when taking pictures of active kids. Is that used in conjunction with 3D tracking or are they two separate actions used for separate occasions? And if they are separate, how is the 3D tracking different than the continuous servo?

3. When using continuous servo, do you continually hold the shutter button halfway down like you do with the single servo?

And here’s my reply….

Not every Nikon has 3D tracking, but I don’t know which models they are. I do know that, of those that do have 3D tracking, it works better on some models than others. For example autofocusing on the D750 is better than the D7000.

The problem with 3D tracking is that the camera struggles to focus when the subject is close to a background, or if the background is a similar colour to the subject. I’ve also heard that green can confuse it, particularly grass.

When talking about continuous servo and 3D tracking, we’re talking about two different aspects of focus: autofocus modes (continuous servo and single servo) and autofocus area modes (single point, dynamic area, auto area and 3D). It’s confusing, because they sound similar.

With continuous servo, the camera focuses continuously whilst depressing either the back button focus button or half depressing the shutter button. With single servo, once focus has been locked it is held until you fully depress the shutter button. If you or your subject moves in that time the subject will be out of focus.

For this reason you can’t use the 3D tracking auto focus area mode when you are in single servo mode.

I use back button focusing, so I keep the back button continuously held down and depress the shutter button only when I want to take the shot. If I weren’t using back button focusing, I would, like you say, hold the shutter button down half way while in continuous servo mode.

Now let’s get into the details…

How to focus on fast moving subjects

Before you begin photographing a fast moving subject, ask yourself if your subject is: 

  • moving erratically (football, hockey, small kids), or 
  • moving in an expected line (runners on a track, ski jumpers, divers).

This will form the basis of many of your focusing choices.

1. Continuous autofocus

As we’re photographing moving subjects, the focus mode needs to be set to continuous-servo AF (AF-C) if using Nikon and AI Servo AF if using Canon.

Use single-servo AF (AF-S) if using Nikon and One Shot if using Canon for still subjects only.

You will need to change your AF-C priority selection depending on what you’re shooting and how fast the movement is. This will vary between RELEASE or FOCUS + RELEASE for Nikon, and for Canon Focus Priority and Release Priority.

The rule of thumb is:

  • Where precise timing is not essential, use FOCUS + RELEASE (Nikon) or Focus Priority (Canon). Examples are skating, surfing, cycling.
  • Use RELEASE (Nikon) or Release Priority (Canon) when the subjects are moving and changing rapidly. Also for when they suddenly appear in the frame. Examples are football, hockey, volleyball, diving or ski jumping.
Focus techniques for photographing children

2. Autofocus area modes

Your next consideration for achieving a well focused image of a fast moving subject is the autofocus area. In other words, how much of the field of view (frame) will be a focus target? There are two autofocus area modes to consider:

a) Dynamic AF area modes (Nikon) or AF Point Expansion (Canon)

b) 3D tracking

a) Dynamic AF-Area Mode (Nikon) / AF Point Expansion (Canon)

How many points of focus you select depends on your subject’s movement and what is around your subject. Let’s look at:

  • Single point AF
  • 9 point
  • 21 point

Single point AF

If there are fixed obstacles between you and your subject, switch to single point autofocus. This will prevent the camera accidentally focusing on something other than your subject.

A sports example would be volleyball – you don’t want to accidentally focus on the net or the ball.

Likewise, it would be a good choice when photographing children running around the park in between the slide and the swings etc.

9 point dynamic area AF

A dynamic area of 9 points is good for most situations as it allows for some subject movement for the camera to track, but doesn’t cover too great an area that might confuse the focusing.

21 point dynamic area AF

If your subject is likely to move towards the edge of your focus area, it is better to use the 21 points dynamic area so that you have most of the area covered. This way if your subject momentarily moves away from your selected focus point, the camera will maintain focus, based on the information from the surrounding focus points.

In addition, if the background is plain, such as the sky behind a ski jumper, a 21 point dynamic area is useful and effective.

b) 3D tracking

This is a Nikon only feature. It is prone to getting confused by the background, especially green backgrounds such as grass. It also can be confused when there isn’t enough contrast between the subject and the background, or if the subject is too close to the background. For these reasons I would not use it and would favour the other focusing options I’ve covered.

DSLR autofocus areas to use for movement

3. Focus tracking duration

Our next consideration is regarding focus tracking and how long we need the camera to track the fast moving subject. To decide on your focus tracking setting, ask yourself 3 questions:

a) How quickly do I need to focus on different subject?

b) Will my subject be moving in an expected trajectory without interruption?

c) Do I need to track my subject past obstacles?

a) How quickly do I need to focus on a different subject?

In a fast changing situation, such as hockey, set focus tracking with lock-on to 1 or switch it off. This reduces the amount of time the camera is locked on, so the response time to focus on a new subject is faster.

b) Will my subject be moving in an expected trajectory without interruption?

The most commonly used setting for focus tracking lock-on is 3. This is the normal setting and is ideal for speed skating, diving, ski jumping, surfing and figure skating.

If you’re photographing one child playing, a focus tracking lock-on of 3 would be ideal.

c) Do I need to track my subject past obstacles?

When your subject is occasionally being obscured, such as runners at a track event, it helps to set your focus tracking lock on to a long lock-on so that you can continue focusing on your subject.

For example, if you’re focusing on a runner overtaking another runner that is between you and your subject, your view of the subject will be temporarily blocked. If your focus tracking lock-on is set to 3 or 5, the camera will maintain focus on your subject and not the runner being overtaken.

5 is considered a long setting and is ideal when photographing pairs of figure skaters.

With a bunch of busy kids running around and playing together, a long lock-on of 5 would be ideal if you’re trying to photograph your child in the middle of the busy crowd.

4. Back button focus

The button to use is the AF-ON button. It is on the back of your camera – hence the name, back button focus. If you don’t have an AF-ON button, you can use your menu to set the AE-L/AF-L button to function as your back button focus button.

I’ve written a separate article about back button focus, so won’t go into too much detail here. What I will say is that back button focusing is essential when photographing any moving subject.

The only time you could capture a moving subject in sharp focus without using back button focus is if you have pre-focused on an area where you expect your subject to be. Examples are a horse jumping over a fence or someone running across a finish line.

In this instance you’d have to use manual focus, or use autofocus to focus on a point and then switch to manual focus, or separate the focus function from the shutter release button to ensure that when you depress the shutter release button your camera doesn’t try to refocus. In other words, disable it’s autofocusing ability.

To do this on a Nikon, select your AF activation as AF-ON, rather than Shutter/AF-ON. For Canon go to custom controls and then shutter button and then select metering start.

Further reading on back button focus: Why back button focus is your BFF, and how to use it

5. Vibration Reduction (VR) or Image Stabilisation (IS)

The last point to consider when photographing fast moving subjects is vibration reduction (Nikon) or image stabilisation (Canon).

Selecting the correct setting will also help to reduce blur. However, if you’re shooting with a shutter speed faster than 1/500 turn off your VR. You won’t need it.

When you’re panning with moving subjects, or are photographing stationary subjects, set your it to ON/NORMAL.

When you are moving and photographing, such as from a moving car, set it to ACTIVE.

How to focus on movement

If you have any questions about how to focus on moving subjects, let us know in the comments.

Also, we love good news, so if our focusing tips have helped you to understand how to focus on moving subjects, share that too.

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