Quickly toggle Ai Servo Focus on the Canon 5D Mark III

Here’s a quick tip for Canon 5D MkIII users.

Canon EOS 5D MkIII with EF 50mm f/1.2L

If you don’t use this camera, this tip probably isn’t very helpful for you. Instead you might be interested to read about how I shot the above photo. Also, I recommend skimming through your camera manual to see what customizations are available. Customizing your camera’s button configuration can help taylor the camera to your shooting style.

With the 5D Mark III, Canon added the ability for users to change the function of several of the buttons on the camera body. In addition to this new functionality, Canon also moved the Depth of Field (DoF) preview button. It’s now on the left side of the lens, in approximately the 8 o’clock position, as you look at the camera’s front.

The new location of the DoF preview button and the ability to assign different functions to the standard buttons brings an interesting new shooting option. As I rarely use the DoF Preview Button, I’ve changed it’s function to toggle Ai Servo Focus when held down. To re-assign the DoF Preview Button to toggle Ai Servo focus mode on the 5D MkIII follow these steps:

1. Navigate to menu C.Fn2:Disp/Operation

Step 1

2. Select the DoF Preview Button from the list of buttons

Step 2

3. Change the button’s function to ONE SHOT AI SERVO

Step 3

This customization allows me to stay in Single Shot AF mode, and toggle Ai Servo focus with my right ring finger if my subject starts moving. This is an incredibly flexible way to handle moving subjects and I like being able to toggle between two AF modes without moving the camera from my eye.

Give this a try and let me know how you like it. It took me a couple weeks to train myself to use my ring finger to toggle Ai Servo, but now that I’m used to it, I love shooting this way. As always, you can find me on Facebook.