Autofocus and Birds in Flight

Published On: January 15th, 2022By Categories: Blog, FUJIFILM, Learning & ResourcesViews: 1764

Many people consider wildlife to be one of the most challenging genres of photography. But that’s a very general statement to make and it is debatable! What isn’t quite as debatable is the challenge of successfully photographing moving wildlife. Being able to accurately and consistently acquire and maintain focus on rapidly moving targets is probably at the top of wildlife photography challenges.

It is no coincidence that the increasing number of pin sharp photographs of moving wildlife such as birds in flight correlates with developments in autofocus technology. There’s no denying the benefits of this technology, but it goes a lot deeper than simply half-squeezing the shutter button.

There is a lot to consider, wildlife can move at remarkably fast speeds often with an erratic and unpredictable path. The surrounding landscape can also present difficulties. Physical obstacles and other wildlife are a perfect distraction for our eye and our camera’s autofocus system.

Modern cameras are full of detailed autofocus settings. We can’t ignore these and expect consistently good results. Ansel Adams said “The single most important component of a camera is the twelve inches behind it.”

Despite the modern technology, this quote remains just as relevant today. We need to understand how the detailed autofocus settings work, how they can be changed and how it affects our photography.

This is quite a lengthy blog post so I’ve added these navigation points if you’re looking for something specific:
Focus Mode | Autofocus Points | Custom AF-C Settings | Aperture, Depth of Field & Shutter Speed | Handhold, Tripod or Monopod? Fieldcraft | Back Button Focus & AF-On | Lens Focus Limiter | Performance Boost | Final Words

Arctic Tern © Alan Hewitt Photography

Arctic Tern, Fujifilm X-H1 & 100-400mm, (1/2500, f/6.4, ISO640, 335mm)

FOCUS MODE

Cameras usually have 3 or 4 basic focus settings, manual and then the autofocus modes; single, continuous and sometimes, automatic. Yes that’s right, an automatic autofocus mode!

Forget manual focus. There is no chance of any consistency if you are manually focusing and tracking a fast moving bird in flight while also thinking about your exposure and composition.

Also, forget single shot autofocus mode. When you half-squeeze the shutter (or activate using AF-On), this mode will autofocus on your subject then ‘lock in’ the distance between yourself and your subject. If you or your subject moves, it will not re-focus until you stop and reactivate the autofocus system.

Automatic autofocus? This is not something we see on all cameras. Canon refer to it as AF A. In this mode, the camera will decide if the subject is moving or stationary and will use either the single shot or the continuous focus mode. Wildlife and birds in flight are a moving subject so don’t waste time letting the camera make this decision.

Continuous autofocus, also known as C, AF-C, AI Servo, C-AF… Different camera manufacturers use different terminology but it means the same thing. Continuous autofocus is the most fundamental setting for moving subjects. As long as your finger is half squeezed on the shutter or activated via a AF-On setting, your camera will continuously focus as you or your subject moves.

As I continue with autofocus settings, the terminology and settings will reflect the Fujifilm X-Mount system I use. Other cameras will have similar set up features so hopefully this blog will still be of use if you use cameras from a different manufacturer.

What about back button focussing / AF-On? I’ll discuss this later in the blog post. But for now, don’t let it confuse issues as it isn’t as relevant as many people have been led to believe.

AUTOFOCUS POINTS

Single Point Autofocus Fujifilm Viewfinder Simulated

Single point autofocus through the EVF

We can further customise autofocus settings to use individual autofocus points to determine the precise location of focus in an image. Typically, more ‘advanced’ cameras are likely to have a greater number of individually selectable autofocus points covering larger areas of the frame. You may also find you can choose the number of focus points available for selection in your set up menus.

With a stationary subject I always use a single autofocus point. I move this around the frame to suit my intended composition and place it on the key area, usually an eye or the head.

When a subject is moving, I use a stepwise approach.

If the subject is moving slowly and predictably and I am able to keep a single autofocus point on the key area, I’ll continue with just a single point. Practical examples may include birds or mammals walking or swimming.

Through the EVF

These two images also show how I customise my electronic viewfinder (EVF). The information we choose to see through the EVF is highly customisable. I prefer to keep distractions to the minimum and this can also contribute to extending battery life. Moving clockwise around the EVF; notification that I am in raw format, my white balance, performance boost, battery status, ISO, exposure compensation, aperture, shutter speed, exposure lock, metering, exposure mode (aperture priority), continuous autofocus and high burst mode. I also have live view highlight alert switched on so I can monitor areas which are overexposed and I find electronic level useful.

If it is too difficult to keep the subject on a single point, perhaps due to erratic or fast movement, then I will set the autofocus to automatically use different autofocus points intelligently from within small groupings.

On my Fujifilm camera this is called ‘zone’. Currently there are three zone sizes available: 3×3, 5×5 and 7X7. This zone can be moved around the frame for composition purposes as you would with a single point.

Just like my stepwise approach to the transition from single point to zone, the size I decide to use is based upon my ability to be able to keep the subject within the zone.

This is led by knowledge of my subject’s behaviour, panning ability and experience and also, use of tripods or monopods (more on that below).

I prefer to use the smallest zone necessary and rely on accurate panning rather than using larger zones.

3x3 Zone Autofocus Fujifilm Viewfinder Simulated

3×3 zone focusing through the EVF

CUSTOM AF-C SETTINGS

Continuous autofocus tracking and speed sensitivity settings can be selected to match how your subject is moving and how the camera should react with potential obstacles.

There are 5 presets:

1. Multi-purpose (Best described as a default or ‘general’ setting)

2. Ignore obstacles & continue to track subject (If we are tracking and panning with a moving subject and there is a potential for interference from obstacles)

3. For accelerating and decelerating subject

4. Suddenly appearing subject

5. Erratically moving and accelerating or decelerating subjects

Fujifilm custom autofocus settings

Custom continuous autofocus settings

Fujifilm custom autofocus settings

Option 6 custom continuous autofocus settings

Furthermore, some cameras have a 6th option where we can adjust the tracking sensitivity, speed tracking sensitivity and zone area switching to create our own autofocus setting.

If your camera doesn’t have this 6th custom setting, I’d recommend using preset number 5, Erratically moving and accelerating or decelerating subjects.

For subjects such as birds in flight I opt for the following custom setting:

  • Tracking Sensitivity: 4
  • Speed Tracking Sensitivity: 2
  • Zone Area Switching: Center

Tracking Sensitivity – higher values mean the autofocus is less likely to hunt by refocussing on distractions once focus has been achieved.

Speed Tracking Sensitivity – higher values mean the autofocus is more sensitive to changes in subject speed.

Zone Area Sensitivity – prioritises the centre of the zone.

Overall, I recommend experimenting with each of these preset custom continuous autofocus settings and the customisable setting. Understanding how they work will help you apply them to different situations.

Once you have mastered your camera’s autofocus system you are well on the way to achieving consistency in overcoming the challenges of focusing on moving subjects. Let’s not forget about the basics though…

APERTURE, DEPTH OF FIELD & SHUTTER SPEED

With most wildlife photography, our goal is to ensure the eye and the key facial features are within the depth of field and sharp.

Consider the ambient light and the colour / brightness of the species you are photographing. In sunny conditions, I’ve photographed Arctic Terns at f/13 thanks to their bright white feathers and the greater depth of field has helped with small focussing errors with this very fast and erratic moving species.

In many cases though, it is difficult to close the aperture sufficiently to ensure the whole bird is within the depth of field. Remember, we’re using long telephoto lenses and we need all of the light we can get to maintain fast shutter speeds.

Generally, I don’t worry about feet, tails and wings drifting out of the depth of field as long as the head is sharp. In many cases, I think blurring of the wings, caused by shallow depth of field or shutter speeds can provide a more dynamic feel to a photograph giving a sense of action and movement.

There is no absolute recommended shutter speed as different species move at different speeds. As a rule of thumb, I would try to keep shutter speeds at around 1/500 sec for large walkng mammals such as leopards and lions. That said, at dusk I’ve photographed a lioness and cubs walking directly towards me at 1/75 sec. It’s far from ideal though, I was relying on luck and this just leads to inconsistent quality and results.

For birds in flight we really need to be above 1/1600th sec but again, there are always exceptions and experience will become a key factor in helping you make this judgement.

Remember, if your shutter speeds are too slow then your autofocus settings and technique are pretty much redundant.

Don’t be afraid to increase your ISO. Cameras and post-processing software are so much better at dealing with high ISO compared to a few years ago. We can deal with noise easily, but rescuing a blurred photograph is altogether a different challenge.

Atlantic Puffin © Alan Hewitt Photography

Atlantic Puffin, Fujifilm X-H1 & 100-400mm, (1/3200, f/5.6, ISO1000, 291mm)

Marsh Harrier © Alan Hewitt Photography

Marsh Harrier, Fujifilm X-H1 & 100-400mm, (1/2700, f/5.6, ISO1000, 261mm)

HANDHOLD, TRIPOD OR MONOPOD?

Black Kite © Alan Hewitt Photography

Black Kite, Fujifilm X-H1 & 100-400mm, (1/1100, f/5.6, ISO500, 280mm)

I don’t know of any tripod and head combination that is as simple and intuitive as using our hips, waist and shoulders for panning and tracking with a moving subject.

If you can handhold your camera and lens it also offers you so much freedom of movement. However, even the lighter long telephoto lenses can quickly put a strain on our arms, especially when the action is happening thick and fast!

A solid tripod is the best option for stability and taking the strain. Choose carefully, not all tripods extend high enough to keep the camera at eye level and it is uncomfortable to be constantly lowering your neck to see through the viewfinder.

Your choice of tripod head is crucial and by far, a ‘gimbal’ type of head is the most suited for photographing birds in flight. My own choice is a Wimberley gimbal but other brands are of course available. This type of tripod head allows effortless, fluid and balanced movement around the camera and lens’ centre of gravity.

If you’re using a gimbal head, it is also worth considering a levelling plate. Some tripods have these built into them already. Placing a levelling plate between the tripod and head is a great convenience. It’s very unintuitive to pan with a gimbal head when you are also compensating for a tripod that isn’t perfectly level. A levelling plate allows you to get level very quickly without making numerous time-consuming micro adjustments to your tripod legs.

A smaller alternative to a gimbal head is the very convenient range of Uniqball heads. These are best described as two ballheads where one acts as a base levelling ball and the other, free movement to pan and track. They aren’t as well balanced as a gimbal head but their smaller size and lighter weight, plus their inbuilt levelling system makes them a good alternative.

Personally, I don’t find monopods an effective alternative to a tripod for extended periods of birds in flight photography. I find they aren’t stable enough to enjoy the balance and movement advantages of a gimbal head.

FIELDCRAFT

Ignore fieldcraft at your peril!

It’s not just about species recognition, safety and ethics although these are very important.

Think about how you position yourself in relation to your subject’s movement and position. Subjects which are moving rapidly towards you represent the most challenging type of constant movement for your autofocus system.

Instead, position yourself so subjects are moving perpindicular or across your field of view. By keeping the subject at a more consistent distance rather than a rapidly decreasing distance you’ll find your autofocus performs much more efficiently as it has much less movement to deal with.

Think about your background too. Autofocus systems are much more efficient at acquiring and maintaining focus with high contrast. Where possible position yourself so there is plenty of contrast between your subject and the background.

Lioness © Alan Hewitt Photography

Lioness, Fujifilm X-H1 & 200mm, (1/1400, f/2, ISO400, 200mm)

Next think about the wind direction. Your camera’s autofocus will perform a lot more efficiently and consistently with a slower subject. If you can position yourself with the wind on your back, a subject which is flying towards you is likely to be flying a lot slower than it would with the wind behind it. Most birds will take off into the wind to gain lift.

A common mistake is to wait too long before focussing on your subject. Get your subject in focus in your viewfinder while it is in the distance. You’ll give your autofocus more time to acquire focus and it will be much easier to track and follow compared to trying to react to something considerably closer. Give your subject plenty of room in the frame too, it’s very easy to clip wings, tails and heads when it gets closer!

BACK BUTTON FOCUS & AF-ON

Some cameras have a dedicated AF-On button. If your camera doesn’t, you may be able to assign this function to another button.

The technique of back button focusing is using this AF-On button to activate the autofocus instead of the traditional half-squeeze on the shutter button method.

A popular misconception is that back button focus is the holy grail for tracking fast moving subjects. There are no cameras (certainly none I know of anyway!) which have some secret super autofocus settings which are only enabled in back button focus. All autofocus tracking settings can be equally applied to shutter button focus as they can to a back button / AF-On method.

Back button focus is about deactivating autofocus from the shutter buttin. This allows you to focus and recompose while in a continuous autofocus mode. I’ve got a seperate blog about this here, Back Button Focusing and AF-On.

Great Crested Grebe © Alan Hewitt Photography

Great crested grebes, Fujifilm X-H1 & 100-400mm & 1.4x t/c, (1/1250, f/8, ISO320, 560mm)

LENS FOCUS LIMITER

Most long telephoto lenses, regardless of prime or zoom, have a focus limiter switch. Careful use of the options on the limiter can be a great assistance to the overall autofocus speed of the camera and lens. I’ll use the Fujifilm XF100-400mm for this example. The XF100-400mm lens minimum focus distance is 1.7m. The focus limiter switch has two options, full and 5m to infinity ∞.

If we set the limiter to ‘Full’, the lens will try to focus using the full distance range from 1.7m to infinity ∞. Generally, it is the closer distances where autofocus systems do the most work to find critical focus. If you know your subject is very unlikely to come within 5m of you and your position, by setting the limiter to ‘5m to ∞’ we are preventing the autofocus hunting in this closer 1.7m to 5m range. The result, more effective and faster autofocus! The critical part is that you must remember you have used the focus limiter switch. If you then try to focus on something which is within the 1.7m to 5m range you will need to switch it back to ‘Full’.

PERFORMANCE BOOST

For cameras with performance options, set to ‘boost’. This increases autofocus responsiveness and performance as well as improving EVF frame rates.

If you use an additional vertical battery grip, you may find a performance selector switch on the body. Otherwise, it can be changed via the power management settings in the set up menu. Performance boost does reduce overall battery life, but it’s worth it!

FINAL WORDS

Learn how your autofocus system works and how you can fine tune it to give you the best possible results. Don’t under estimate the importance of some fieldcraft knowledge and make sure you continue to use the fundamental knowledge too, i.e. aperture and shutter speed.

Applying the technical aspects, the technique and the fieldcraft means there is an awful lot to think about and more often than not, in a very short space of time!

Don’t get disheartened if it takes quite a while to come together. Above all else….. practice!

This blog post is an update to an older blog post I wrote a while ago. It covers my approach and you may find you have different techniques and settings which work better for you.

Azure winged magpie © Alan Hewitt Photography

Azure winged magpie, Fujifilm X-H1 & 100-400mm, (1/1700, f/6.4, ISO2000, 219mm)

Bonelli's Eagle © Alan Hewitt Photography

Bonelli’s Eagle, Fujifilm X-H1 & 100-400mm, (1/800, f/5.6, ISO640, 400mm)

Grey Heron © Alan Hewitt Photography

Grey Heron, Fujifilm X-T4* & 100-400mm, (1/1250, f/5.6, ISO200, 400mm) *Pre-production camera

Arctic © Alan Hewitt Photography

Arctic Tern, Fujifilm X-H1 & 100-400mm, (1/1700, f/6.4, ISO640, 323mm)

Atlantic Puffin © Alan Hewitt Photography

Atlantic Puffin, Fujifilm X-H1 & 100-400mm, (1/2200, f/5.6, ISO1000, 270mm)

Leopard © Alan Hewitt Photography

The Fujinon (Fujifilm) 100-400mm f/4.5-5.6 attached to the Fujifilm X-H1

Ostrich © Alan Hewitt Photography

Ostrich, Fujifilm X-H1 & 100-400mm, (1/680, f/5.6, ISO400, 400mm)

Ostrich

Izzy, Fujifilm X-H1 & 70-300mm*, (1/450, f/5.6, ISO200, 300mm) *Pre-production lens

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