Back Button Focus: Making Focusing Easier

April 29, 2016  •  2 Comments

There are still many people that have not heard of back button focusing, and of those that have there are many who are not entirely sure of its benefits. For me, using the back button focus is a real game changer in all all types of photography but especially for sports and wildlife.

Canon cameras have the equivalent of One-Shot or AI-Servo modes.  For Nikon users, you can shoot in AF-Single (AF-S) or AF-Continuous (AF-C). Those using One-Shot and AF-S modes mean that your camera focusses at the point you half-press the shutter button. If your subject moves (which is guaranteed to happen at some point with wildlife) you have to release and repress the button to focus again. As a result, most photographers will find themselves looking away from the viewfinder to change between the two modes depending on the type of scene they are shooting. This is precious time, and can often result in missing shots.

Back button focusing allows you to separate the focusing action from the shutter button. So instead you press AF-On when you wish to focus. This allows you to remain in AI-Servo /AF-C mode whilst maintaining the benefits of being able to focus and recompose your shots like in One-Shot or AF-S.

 

Here’s an example of using the AI Servo to lock focus and recompose:

Whilst photographing this great grey owl perched in the tree, I was using back button focusing. I pointed the chosen focal point (the center point, as it is most accurate) at the owl and pressed AF-On to focus. Then, having released AF-On, I was able to recompose the shot and press the shutter to take the image. All the time in AI Servo mode!

 

December Projects 2014-021Great Grey Owl

 

 

Here’s an example of using Back Button Focus along with AI Servo to track the subject:

Are you more into action photography? Then the biggest advantage of using back button focus is for you.  Each time you have a moving subject you just need to simply press and hold the AF-On button and follow the subject while in AI Servo mode.  The camera's AF system will do it's best to track the subject allowing you to concentrate on pressing the shutter button to capture the image while everything is happening quickly right in front of you. There are many advancement to AF tracking, especially in the newer cameras.  Canon, for one, offers adjustments case settings which help the AF system track more effectively.

 

Florida Getaway 2016-052Florida Getaway 2016-052

 

There are other reasons why you should make the change, too. You’ll never have to fiddle around with the dials to switch to manual focus. Just don’t press AF-On, manually focus the lens with the focus ring, then press the shutter, and your adjustments aren’t altered.   It will not make any adjustments to the focus until you press the AF -On again.
 

Making the Switch

I imagine that by now you have decided you want to make the switch – at least just to try it out.

 

For Canon Users

Go to your menu and head to Custom Functions. Select the shutter button, and change its function to Metering Start. Then change the function of AF-On button to Metering and AF Start.

 

For Nikon Users

Go to your menu, and enter the Autofocus custom menu. Scroll down to AF activation and switch it to AF-On only.

Some older Nikon camera users will find this under the AE-L/AF-L option.

 

Still not sure and want to see it in action then watch this video by Tony Northrup as he explains it in more detail

 

And remember... 
Life is short... so go make some images to remember the journey along the way!


Comments

2.MH PhotoDesigns, LLC
Yes Milton, for any action photography were you need to track the image you just simply press and hold the AF On button while in AI Servo mode and follow the subject. The AF system will do its best to track the subject so all you need to do is press the shutter button to capture the images you are after. There are many advancements to AF tracking, especially in the newer ones. Canon offers adjustments to case settings which help the AF system track more effectively.
1.Milton Findley(non-registered)
Marcus, what if you were shooting a BIF, would you just point and hold the AF On button down while trying to get the shot?
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