4 Benefits of using Back Button Focus in wildlife photography

Andrew Beck All Authors, Andrew 7 Comments

A while back I shared a a post on the power of back button focus in wildlife photography and I am planning on recording a video blog on this same topic in the near future. This past weekend I was asked about the benefits of shooting using back button focus and I thought this would make for a great blog post.

1. You can Shoot in AI-Servo (AF-C) and One Shot (AF-S)

Why would you want to do this? More often than not we are working with subjects that will be moving erratically. Whether its a lioness walking across the open plains, or a buffalo grazing in the marshes, the distance between the camera and our subject is almost always changing. In AF-C (or AI-Servo) the camera’s autofocus system is continuously adjusting focus on your behalf in order to render a crisp, in focus image when you trip the shutter.More often than not I’ll be using the central focus point as this is the fastest and most accurate of the focus points available and still leaves some margin around my subject in terms of achieving the desired composition.

Andrew Beck Wild Eye Back Button Focus-2

What happens when the subject stops or you want to get a bit more creative with your composition?

More often than not you’ll be wanting to compose and leave some negative space to help you tell the story in this scenario. Whilst still being in AI-Servo I have two options to achieve this:

  • I can manually adjust my focus point to suite my composition and continue to depress the AF-ON button which engages the autofocus
  • I can use the central focus point to achieve focus before releasing the AF-ON button and recomposing

I typically use a combination of both of these methods, especially when a subject is at close range or shooting at large apertures such as F2.8, as even the smallest of changes in distance can effect the accuracy of your focus and resultant depth of field. I will usually select a focus point closest to the centre of the frame which compliments my intended composition before fine tuning my focus points.

In the image below, the red focus block shows where my outermost right-hand focus point was originally engaged in order to achieve focus. The orange dotted line shows the movement of the camera to the left and the final resting place of the same focus point after I had achieved my intended composition. Had a made use of the central focus in this instance, there would have been a good chance that my focus and resultant depth of field would have been off.

Andrew Beck Wild Eye Back Button Focus move point

Andrew Beck Wild Eye Back Button Focus

Always make use of the nearest focal point to your subject before recomposing in order to maintain maximum accuracy with focus and depth of field. 

2. You can manually focus without needing to adjust settings on your lens

How many times have you been frustrated by your lens “hunting” for focus in low light or busy scenes? Since the Autofocus is only engaged when you press the AF-On button, you can take complete control of the manual focus on most lenses without your camera overriding your focus when you release the shutter.

This is very handy for busy scenes where the camera focusses on obstacles in front of the subject, and in low light where there is not enough contrast for the camera to achieve focus.

Andrew Beck Wild Eye Back Button Focus-3

3. You save time by not switching between modes

Sometimes the precious time that it takes to pull your head back from the viewfinder and adjust modes means you miss the shot. With back button focus setup you can essentially control all variables without needing to pull your head back from the viewfinder, meaning that you will have a better chance of capturing the action.

Andrew Beck Wild Eye Back Button Focus-4

4. Other people will think your camera is broken and wont use it!

So this could also be seen as a potential downside but most people who pick up your camera to shoot wont be able to achieve focus. Something to remember when asking someone to take a group shot!


About the Author

Andrew Beck

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Very few people can tell you what their passion in life is. Even fewer will be able to tell you that what they do for a living is in fact their passion. My love for the bush and conservation took me on journey which would not only allow me to explore the continent which fascinates me so much, but to share my passion for photography and conservation with others. Be sure to check out my my website and instagram account.

Comments 7

  1. Judy Royal Glenn

    Thank you Andrew for sharing your tips and knowledge of back button focusing. I am one who does not like to try new things, but from what I have read, I think it will help my photography exponentially. I agree the combination of the AF-C and AF-S would be a wonderful option while photographing wildlife. I love photographing wildlife, especially hummingbirds! Thanks ~ Judy

    1. Post
      Author
      Andrew Beck

      Hi Judy

      Thanks so much for the comment and feedback. I should probably have mentioned this but this system is great for pre-focussing on a branch or perch and waiting for a bird to approach and land. Stop down to F8.0 or so to give yourself a bit of room to play with and then pick the moment as the bird stalls to land. You’ll have a far greater success rate with this than you would if you tried to track a small bird like a hummingbird.

  2. Barry

    Back button focus is definitely one of the best “tricks” I ever learnt, I find it interesting that you still move your focus point around for wildlife shots though, I find the focussing with the centre point and recomposing one of the most useful and time saving benefits of back button focus. With wildlife I’m always concerned that the subject might move before I get the right focus point and then I want to use a different one. Do you ever find that or do you only change focus point with a relatively stationary subject? (Although I must admit it could be a bit to do with the camera, I found the joystick on my 40D a lot easier to use than the direction pad within the main control wheel on the 70D.)

    I definitely agree about using f2.8 and the caution/precision needed to achieve sharp focus! I went through a patch where I shot all my wildlife at f2.8 and couldn’t figure out why my focus was off on so many shots! Playing around with the variables in a DOF calculator was an eye opener!

    1. Post
      Author
      Andrew Beck

      Hey Barry

      Glad you’re enjoying back button focus. I too used to use the central focus point a lot in the beginning but did notice that my images were not as crisp as I had wanted them to be. I attributed this to the subtle changes in distance that occurred when recomposing and started to achieve focus with the focus point nearest to my intended area of focus before recomposing. The buffalo image in the blog is a great example as you can see just how far the central focus point would be away from the actual intended area of focus.

      In terms of the time it takes to shift the focus point, I find this almost negligible but must admit that I am very comfortable with my camera setup. It does take a bit of getting used to (This has given me another idea for a blog post by the way!).

      This obviously becomes more of an issue at larger apertures and shallower depth of field. Give it a try as it is a good habit to get into!

  3. Kelly

    Hi, thank you for your sharing. This is a very useful tips for me. May I ask how many focus point do you use? single? 11 points? 51 or rather group area AF ?
    Thank you very much.
    From Hong Kong.

    1. Post
      Author
      Andrew Beck

      Hi Kelly

      It all depends on what I am photographing at the time but typically I make use of a single focus point but will expand the AF from a single point to a specific zone (for moving subjects) or even the entire AF area (for birds in flight).

      I hope this answers your question?

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