Advanced focus techniques for sharp photos of moving subjects

One of the biggest challenges when it comes to capturing moving subjects in photography is making sure that your subject is in sharp focus. When a subject is moving, it can be very difficult to keep up and focus.

I got the idea to write this tutorial when one of our readers left a comment on the Nail your Autofocus tutorial asking for advice on photographing busy kids. They particularly mentioned Nikon’s 3D tracking and continuous servo, so I’ve included her questions and my answers at the end.

Capturing moving subjects in photos involves more than just focus and applies to many more situations than just photographing children.

For example:

• Sports photography, including your kids’ sports
• Young children playing
• Pets running around
• Birds in flight

How a subject moves determines how you photograph it

Before you begin photographing a fast moving subject, ask yourself if it’s moving:

• Erratically (football, hockey, small kids)
• In an expected line (runners on a track, ski jumpers, divers)

This will form the basis of many of your focusing decisions and camera settings.

Camera settings for capturing moving subjects

We’ll look at these 6 photography techniques and camera settings for focusing on moving subjects:

1. Continuous autofocus
2. Autofocus area modes
3. Focus tracking duration
4. Back button focus
5. Pre-focus on a point
6. Vibration reduction / Image stabilization

To receive the cheat sheet on autofocus areas shown further down, just pop me your email address and I’ll send it over to you. It’s for Nikon and Canon cameras, but the autofocus areas are similar for other camera makes too.

Now let’s get into the details…

1. Continuous autofocus for moving subjects 

When photographing moving subjects, set the focus mode needs to continuous-servo AF (AF-C) if using Nikon and AI Servo AF if using Canon. Continuous autofocus is also known as continuous shooting mode, or burst mode.

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

AF-C priority selection

Set 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.

To focus on moving subjects the rule of thumb is:

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

2. Autofocus area modes to use for moving subjects

Your next camera setting to adjust for a sharply focused image of a fast moving subject is the autofocus area. In other words, how much of the field of view (frame) will be occupied by the focus target (subject)?

The two autofocus area modes to consider are:

• Dynamic AF area modes (Nikon) or AF Point Expansion (Canon)
• 3D tracking

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

The number of focus points you should set depends on your subject’s movement and what’s around your subject.

Choose from:

• Single point AF
• 9 point
• 21 point

Single point AF

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

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

It’s also a good option when photographing children running around the park in between the slide and the swings etc.

9 point dynamic area AF

A dynamic area autofocus of 9 points is good for most situations involving a moving subject.

9 points allows for some subject movement for the camera to track, like with panning photography, but doesn’t cover too great an area that might confuse the camera’s autofocusing.

21 point dynamic area AF

If there’s a chance your subject will move towards the edge of your focus area, rather use the 21 points dynamic area autofocus 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 autofocus is particularly useful as it won’t get confused by an object in the background.

b) 3D tracking

3D tracking is a Nikon only feature for focusing on fast moving subjects.

While it sounds great, 3D tracking can easily be confused by the background in an image when:

• The background is green, such as grass
• There isn’t enough contrast between the subject and the background
• If the subject is too close to the background

So, 3D tracking isn’t ideal for many types of sports photography.

For these reasons I wouldn’t use it and would favor the other focusing options I’ve covered.

3. Focus tracking duration for moving subjects

The next camera setting to consider is focus tracking, which is how long you need the camera to track the fast moving subject.

To decide on your focus tracking setting, ask yourself 3 questions:

• How quickly do I need to focus on a different subject?
• Will my subject be moving in an expected trajectory without interruption?
• Do I need to track my subject past obstacles?

Let’s look at each one…

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

In a fast changing sports photography 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 sports photography setting for focus tracking lock-on is 3. This is the normal setting and is ideal for:

• Speed skating
• Diving
• Ski jumping
• Surfing
• Figure skating

It’s not just for sports photography though.

Because small children are always busy and move erratically, a focus tracking lock-on of 3 is ideal for capturing sharp photos of children playing.

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

In sports photography, 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 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 focus tracking setting, so it’s ideal when you need to hold the focus for a while, such as for photographing pairs of figure skaters.

With a bunch of busy kids running around and playing together, a long lock-on of 5 would also be ideal for photographing your child in the middle of the busy crowd.

4. Use back button focus to capture moving subjects

The button to use for back button focus is the AF-ON button and it’s 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 setting 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 with a DSLR camera.

To remove the focus function from the shutter release button for BBF:

• Nikon – select your AF activation as AF-ON, rather than Shutter/AF-ON.
• Canon – go to custom controls and then shutter button and then select metering start.

5. Pre-focus on a point for sharp photos

The only time you could capture a moving subject in sharp focus without using back button focus is if you’ve pre-focused on an area where you expect your subject to be.

Sports photography examples ideal for using pre-focusing are:

• a horse jumping over a fence
• a runner crossing the finish line

You have 3 options to pre-focus your camera:

• Manually focus on a point ahead of time
• Autofocus to focus on a point and then switch to manual focus
• Use back button focus and separate the focus function from the shutter release button so that when you depress the shutter release button your camera doesn’t try to refocus. In other words, disable the shutter button’s autofocusing ability.

6. Vibration Reduction (VR) or Image Stabilization (IS) for moving subjects

The last camera setting to adjust is vibration reduction (Nikon) or image stabilization (Canon).

However, when photographing with a shutter speed faster than 1/500, turn off your VR. You won’t need it.

Vibration reduction / Image stabilization settings

The two vibration reduction camera settings you can use are active or normal. Set your vibration reduction to:

• ON/NORMAL – when you’re panning with moving subjects, or are photographing stationary subjects.
• ACTIVE – when you’re moving and photographing, like when photographing from a moving car.

Summary of how to capture moving subjects

If you’ve skipped to the bottom, here’s a quick summary for sharp photos of moving subjects…

1. Decide if the subject is moving erratically or in an expected line
2. Switch to continuous focus instead of single servo (one shot)
3. Decide on the best AF-C priority for the situation
4. Select the best autofocus area mode for the type of movement and activity
5. Set focus tracking duration based on line of view to your moving subject
6. Use back button focus
7. Consider pre-focusing and isolating the shutter button
8. Decide on active or normal vibration reduction / image stabilisation, or switch it off

Questions I was asked on photographing 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?

My answer….

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.

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