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All you need to know about BACK BUTTON FOCUS





An Intro to Back Button Focus

What exactly is back button focus? Most cameras focus by half pressing the shutter button where it focuses and when you completely press it all the way down. Back button focus is taking the focus ability away from the trigger or shutter button and assigning it to a back button instead. All that the front shutter button will then do is start the light metre and take photos.

The focusing of the camera is now controlled by the back button. When you press it down, the camera focuses. When you release the finger it stops focusing.





Most cameras have two types of focus modes, a 1 shot mode and a continuous mode. In one shot mode, the camera freezes the focal plane at a certain spot and as you keep taking photos, it keeps taking them at that one focal plane. Continuous focus means that the focus point moves back and forth. This is very useful for wildlife photography as most of the time your targets are moving and make it very difficult for the one shot mode. AI servo on Cannon, Nikon and Sony are referred to as AFC known as autofocus continuous, so remember.






Keeping the Focus Point on a Still Subject

Sometimes when you're taking photos you don't want the focus to change. Most cameras have focus points in the centre of the frame and there are times when you want to have the subject for composition purposes often to the edges of the frame. If you move your subject off to the edge and the focus points in the centre are pointed on the background, your camera will try to refocus on the background and your subject will no longer be in focus. Using back button focus, it avoids this problem.





By pressing the back button focus while pointing on your subject and then releasing your thumb, your subject will be focally locked in place. When the camera is moved, your camera is no longer trying to refocus on the background that its still focused on. In this case, you can move your target all around the frame as much as you want and your camera is not trying to refocus. You can move the subject around the frame for better composition only if it has remained in the same spot.

If how ever you have noticed your subject has moved forward or backwards, you would need to use the back button focus to refocus on the subject where you can again have the freedom to move the subject around the frame for changing composition.





Back Button Focus - Avoiding Objects

Another benefit of using back button focus is when there are obstructions in front of your animal. In this scenario, if your try to focus on an animal such as this Baboon surrounded by grass, there's a chance that the auto focus will try to focus on a vegetation in front of the subject. Instead you can aim the autofocus point to the edge of the baboon where the grass is not present. I will take my finger off the back button focus and then recompose my shot and take the shot.







Back Button Focus - Submerging Hippos

Another very helpful way to use back button focus is when photographing hippos in rivers or pols of water. I would use the back button focus to focus on the head of the hippo and then release the button. Once the head of the hippo will submerge, the auto focus will not be able to focus on the surrounding water and will remain in focus on the area of where the hippo submerged. Usually the hippo would re appear out of the water and your focal are that was locked in place by the back button focus would help you capture or re-focus on the hippo with out your camera refocusing on the surrounding water.







Back Button Focus - Nesting Bee Eaters

Another helpful scenario would be when waiting for small birds to reappear out of nest holes from which they fly into and flying out. When set up nearby using a tele lens, you would use the back button focus to focus on the bird as its head pops out of the hole. Once you have the bird in focus, you would release the button and your set up to capture as many shots as possible as that focal area is set. You can actually photograph continuously to capture the full body as the bird exits the hole. This will help you not worry about the camera accidently focusing on the vegetation surrounding the hole.







Setting up Back Button Focus (BBF)

This will be based on setting up your back button focus on an SLR and a mirrorless Canon camera. To get it into your head, you need to assign the focusing ability from the shutter button to the back button focus button. We will provide you the how to information for a CANON.



CANON BBF Setup


Setting up a Canon SLR (Based on the R5)

  1. Press the Q button and select the icon for customising dials and buttons.

  2. Now press the shutter button located at the upper left and select.

  3. Change from (Metering and AF Start) to (Metering Start) and click set.

  4. Now press the AF on button located below.

  5. Change the original setting to AF and press set.

  6. Your good to go!

Setting up a Canon Mirrorless (Based on the 7D)

  1. Press the Q button and select the icon for customising dials and buttons.

  2. Now click Customize Buttons

  3. Change from (Metering and AF Start) to (Metering Start) and click set.

  4. Now press the AF on button located third down from the top.

  5. Change the original setting to AF and press set.

  6. Your good to go!

What's Next?

Having gone through this simple alteration for your camera, the next in the field camera body blog will go through the workings of when and how to use the eye tracker in all different environments. I will also go though how the eye tracker can help you gain those images that you die for and when not to use it and rely on your human capability instead.







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