MARKUS VARESVUO

FOCUSING METHODS AND HOW TO USE THEM

Autofocus revolutionized flight shots less than two decades ago.

Before autofocus, focusing was done manually, and you relied on your eyesight. Trying to take sharp images of flying birds was very hard, especially when they flew close. Now you see one great action shot after another, and most of them were taken with continuous AF.

Bird images are primarily taken with autofocus. You typically use continuous focusing when photographing moving subjects and one-shot focus for subjects that are still. You occasionally need to use manual focus, which we’ll talk about more at the end of this chapter.

When you use continuous focusing, you try to keep a chosen AF point, or points, locked on your subject, such as a flying bird, so that the camera processor can calculate and estimate the subject’s flight path. In an ideal situation, you can admire a long series of sharp images after photographing a flying bird and decide to keep only the images in which the wing positions and the background please you most. Unfortunately, the reality is often very different, and in the most challenging situations you can count yourself lucky if you get one sharp frame.

The success ratio is best when photographing relatively large birds against an even background, such as a blue sky, and the bird is quite big in the frame. You can use one AF point because it’s fairly easy to keep it locked on the bird, for example on its head. Most camera makes and models with autofocus can produce sharp images in such situations with a good success ratio, as long as the shutter speed and other adjustments are correct (read more about this in the chapter “Freezing Movement”).

An essential basic adjustment to make on your lens is to select the working distance. For photographing flying birds, you should select the option with a focusing range from the largest available number of feet to infinity. This makes the focusing faster, especially the refocusing that has to happen after your subject has disappeared from your viewfinder.

When photographing a fast bird against a busy background, the success ratio drops noticeably, even with the best professional cameras. With Canon’s professional models, your best option for this kind of situation is the slowest or second slowest tracking sensitivity, which helps to keep the focus steady and prevents it from switching to the background. Also, birds that fly fast in erratic paths can prove difficult, even impossible, to track with just one AF point, and you could be better off using an extended central AF point (four or eight extra points); if the central AF point loses the subject, the surrounding AF points become active and can lock onto the subject.

A Common Crane flying against a blue sky (Grus grus)
Canon EOS-1D Mark II N, 500mm f/4.0, 1/1250 second, f/8.0, ISO 400, continuous focus with a central focusing point, handheld camera, blind. Sweden, April 2007.

A Lammergeier flying against an alpine background (Gypaetus barbatus)
Canon EOS-1D Mark IV, 500mm f/4.0, 1/2000 second, f/8.0, ISO 800, continuous focus with an extended central focusing point (the left edge of the image has been cropped), Gitzo tripod, Manfrotto 501 video head, blind. Spain, November 2010.

Sometimes, when the circumstances are really challenging, even the extended central AF point is not good enough to keep a flying bird in focus for any length of time, and it’s better to use the largest number of AF points, such as 45 points, or 61 points with the Canon EOS-1D X. This way it’s likely that at least some part of the bird is in focus, provided that it’s in the viewfinder to begin with.

I used to select 45 AF points often, and in easier circumstances, with good results. This worked delightfully well in the Canon EOS-1D Mark II camera, and satisfactorily with the EOS-1D Mark IV, whereas I hardly ever used it with the EOS-1D Mark III, where the 45 AF points was hopeless. I now have some experience with the new EOS-1D X and can safely say that the 61 AF points is the best focusing system that Canon has ever engineered. It poses a serious threat to the hegemony Nikon has had over focusing in the past few years. For flying birds in demanding circumstances, the 61 points work so well that I’ve all but scrapped the use of one AF point or even the extended AF points. One exception, where the extended central AF point has proved better than the 61 points, is photographing fast-flying seabirds against sharp waves from a heaving boat.

One-shot focus is mainly used for birds that are still. Using one-shot focus means that you aim your AF point to the desired spot and press the shutter release halfway down. The camera focuses on the spot and locks it; you can either take several frames with the same focus by pressing the shutter release all the way down or move your camera to reframe for better composition before pressing the release fully down. To refocus, let go of the shutter release and then press it again.

Some photographers use continuous focusing even on stationary birds, but I recommend using one-shot focus because its focus is more accurate and it makes composition easier. Keep in mind that when you’re taking closeups and using the largest possible aperture, the focus area is very shallow. To ensure that you will get shots where the subject, or the desired part of it, is in the focusing area, focus on the target several times and take many frames.

One-shot focus is also good when you prefocus on an area in anticipation of an action image, where continuous focus would have no chance of tracking the subject. For example, first you prefocus on a nest hole entrance, then you set your lens focus to manual. As soon as you see the bird getting close to the nest, take a series of images and hope that at least one frame has caught the bird in the right position and it’s sharp in the frame. This will probably yield better results than continuous focus.

I took the Common Redstart image using one-shot focus. I followed a Common Redstart parent for a couple of days, photographing from a blind. The bird always used the same route to return to the nest with food for the young, and it always stopped on the same perch for a second or two before making a short movement, practically vertically, into the nest. First I tried using the continuous focus, but it was mostly locking on everything except the head—the focus was probably deceived by the quick opening of the wings as the bird took off. I needed a new strategy, so I started using one-shot focus, which I aimed at the bird’s head the second it landed on the perch. Then I pressed the shutter release to fire a series of images until the buffer was full or until the bird was out of the frame. A few days later I had many decent images.

A Common Redstart bursting into flight (Phoenicurus phoenicurus)
Canon EOS-1D Mark III, 500mm f/4.0, 1/2500 second, f/4.5, ISO 2000, one-shot focus with a central focusing point, Gitzo tripod, Manfrotto 501 video head, blind. Vaala, Finland, June 2007.

Use manual focus when the autofocus isn’t working for some reason, such as the following: