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Who uses * (CF-4) for focusing and why?

Nill Toulme

New member
Here's Jonathan's article. I don't know if 5D offers the same option. Note that on Mark II 1-series you can set * to center point and AFPS to X, which I find highly preferable, and which is opposite to way Jonathan describes it in his article (because you could only do it opposite to that on the original 1-series).


Bob Krueger

New member
Yes, Nill, the other custom function is 18, which if set to other than zero allows access to the registered AF point by using only the assist (X) button) rather than having to press both the assist button and AF buttons simultaneously. I set CF18 to 2 so that as long as I hold the button, the registered point is active and the focus will track in AI-Servo mode. Setting it this way means that I can push and hold the X button to track for my motorsports stuff, but also just push and release if I want to focus on a static subject and and then recompose before firing the shutter, or pre-focus on a point on the track and fire a burst without refocusing at all when the cars arrive. CF18-2 and CF4-3 work together to be a very versatile setup for me no matter what I want to do.

I think the Jonathan Wienke article to which you refer is here.

By the way, there is a very good summary of the 1DMkII custom functions and how their various options work here.

There is a related summary of personal functions here.

Mike Johnson

New member
For wildlife, separating the focus from the exposure (when in Av or Tv) and shutter trigger is very helpful. You can also easily switch between center focus and the 45 point sensor by using your thumb on the back. It took awhile to get used to, but I really find it helpful.

Sadja Herzog

New member
focus - shutter/meter

Seems to me that focus, whether single shot or ai servo is one thing. Shutter release is another. Metering is the third and it is tied to the shutter. I will often focus on the subject (single AF) move the viewer to another area where I want the meter to take its reading, half press to lock in the reading, recompose and shoot.

Dan Lovell

New member
Will It Encourage Bad Habits?

Swapping the AF function from the shutter button to the * button may well have it's use, but in general, I rather not do that if it encourages me to Lock-Focus-Recompose, or enocurages me to rely solely on the center FP.

René Damkot

New member
Why would it encourage FLR? I use whatever AF point is closest to the subject...

Remember that in Evaluative, metering is 'biased' to the manually chosen AF point.

I use CF4-3 mainly because I disliked the fact that 'default' operation for Canons seems to be to lock AE simultaniously with AF, when using OneShot/Evaluative. (All Canon camera's apart from the 10D also exibit this behaviour when in CFn4-3 while keeping '*' pressed!)
Therefore I use AiServo with CFn4-3 now mostly...
CFn 4-2 seems like an option, but the other way around: You have to press '*' to lock AF and resume metering when in OneShot/Evaluative. Drawback seems, you loose the ability to rapidly switch to another AF point by pressing 'X'...

Philip Chong

New member
I have used CF-4-1 since the original EOS-1 film camera of 1989, and using this feature has been 2nd nature to me with each successive 1-series EOS, film or digital. Until the EOS-1D Mark III made its appearance last year.

Combination of the AF-ON and shutter button to make AF works took some time getting used to. Using one for AF automatically cancels out the other but I found out this practise is not feasible in AI Servo AF mode when the main subject remains static and not within any of the 45-point AF sensor mark. Due to this, I activated the C.Fn to have AF activation exclusively on AF-ON button and disabled it from the shutter button.

It also took me quite a while to get used to activating the AF-ON button with my right thumb as it would be closer to the * button and the C.Fn option to switch AF operation with the * button and AF-ON was utilized instead.

However, after having used the EOS 40D for nearly a month, using the AF-ON regularly with my thumb is no longer a hassle. And using the same style on the 1D Mark III is no longer an issue either.