EOS-1D Mark III: AF custom function settings

The EOS-1D Mark III has a plethora of Custom Function settings making it easy to personalise. However, it can be a bit of a minefield if you don’t know where to start.

The EOS-1D Mark III has a completely re-designed autofocus system that gains much of its performance improvements from the increased sensitivity and instant response. However, it is precisely this instant response and heightened sensitivity that can catch you out if you’re not expecting it.

Fortunately, all the Custom Functions allow an enormous range of flexibility in how you set up the camera so it can be tailored to your needs.

If you’re photographing fast moving subjects and are struggling to use AI SERVO to track them reliably, there are a few of the custom functions you should take a look at, as well as a potential change in the way you work.

Most photographers will tend to use the central focusing point as in previous EOS cameras it was the most sensitive. With the EOS-1D Mark III however, all AF points are as almost sensitive as the central focusing point. With the EOS-1D Mark III, the other focusing points have been further refined and, depending on your subject, you may find it easier to focus by using one of the off-centre points. It should also provide more flexibility in composition.

1

C.Fn III-2

The heightened sensitivity of the EOS-1D Mark III AF system can, in some situations, cause the autofocus to appear erratic. In fact, it is not erratic at all, simply it is so sensitive that it will identify and re-focus on a new subject much faster than previous cameras – and crucially – much faster than you might expect.
Turning down this response rate to ‘Moderately Slow’ or ‘Slow’ will help when tracking subjects as the camera will not jump instantly to any new ‘subject’ or the background and should ensure a more familiar AF response. Note that this will not slow down the speed of the autofocus, only the speed at which the camera recognises a new subject. It’s like a buffer than provides you with more time and leeway to track a subject without the camera constantly finding new ones.

2

C.Fn III-8

Expanding the size of the active autofocus point will improve the tracking of the camera as it will stand more chance of holding focus if the main focus point moves from the subject to the background. (The AF speed is the same even is III-8-2 is used.)

3

C.Fn III-4

When you activate C.Fn III-8-1 or -2, it is best to also set C.Fn III-4-1 so the camera will continue to track the main subject, even if a ‘subject’ moves to the foreground and is therefore covered by one of the active AF points - a swimmers hand moving in front of their face, for example.
This custom function will be operation in automatic AF point selection mode, or if C. Fn III-8 is set to –1 or –2 in manual AF point selection mode.

4

C.Fn III-5

When tracking subjects against a background with little detail, a bird in flight, for example, if the AF point moves from the subject to the background, the camera can begin to ‘hunt’ for a subject to focus on. Setting C.Fn III-5-1 will stop the camera hunting – and risking a completely out-of-focus situation while the lens searches for a subject to focus on – so when the AF point re-finds the subject, it can re-acquire focus faster.