Ques. about 80D auto-focus: How does the initial point get set/determined?

Started 4 weeks ago | Discussions thread
ohaya
OP ohaya Regular Member • Posts: 143
Re: Ques. about 80D auto-focus: How does the initial point get set/determined?

ohaya wrote:

Sharlin wrote:

C.Fn II-11 Initial AF Point, AI Servo AF

You can set the AI Servo AF’s starting AF point for when the AF area selection mode is set to Auto selection: 45 pt AF.

0: Auto

The AF point which AI Servo AF starts with is set automatically to suit the shooting conditions.

1: Initial AF pt selected

AI Servo AF will start with the manually-selected AF point when the AF operation is set to AI Servo AF and the AF area selection mode is set to Auto selection: 45 pt AF.

2: Manual S AF pt

If you switch from Manual selection:1 pt AF to Auto selection: 45 pt AF, AI Servo AF will start with the AF point that was manually selected before the switch. Convenient if you want AI Servo AF to start with the AF point that was selected before the AF area selection mode was switched to Auto selection: 45 pt AF.

So, basically, the alternatives are:

0: Let the camera decide

1: Assign one AF point to be always used as the starting point

2: Use the point that was last selected in one-point AF mode.

Hi,

Thanks. I have been reading and re-reading the in-camera help and also doing testing, and I am not able to see the difference between when I select "1" vs. "2" options.

Sorry, to be clear, I am NOT trying to be argumentative, but I am really confused, so let me try to ask some questions, because I am wondering if my confusion is because of terminology?

1) Is it correct that you can only select the starting point for the "45 point AF" area, and that you cannot select the specific individual starting point for either the "Zone AF" or "Zone AF, Large" areas?

I think that that is part of what is confusing me. I thought/imagined/assumed that there was a way to select the starting point for all 3 of those "area selections" (i.e., "for Zone AF", "Zone AF, Large", and for "45 point AF".

2) Looking between the help for option #1 and option #2, I'm having a hard time "visualizing" the difference between option #1 and option #2 (I think because the wording is a little convoluted):

AI Servo AF "starts with" the AF point you selected "as the initial point" when switching to 45-point auto selection AF.

vs.

AI Servo AF "continues from" the AF point you selected "for single-point AF" when switching to 45-point auto selection AF.

Can you help me understand that a little better?

Thanks,

Jim

Hi,

Ok, I just did another test (and re-read what you said about "basically"), and I *think* I understand.

So with option #1, the 45 point AF will ALWAYS start at the point that you had configured as the starting point in the 45 point AF, regardless of if you had been using a different focus point in single point AF AND THEN SWITCHED TO 45 point AF.

Is that right?

Whereas, with option #2,  when you switch the camera from single point AF to 45 point AF, whatever point you had selected when you were using single point AF will become the starting point for the 45 point AF.

Is that right?

I guess that I am not sophisticated enough yet to even imagine why you would want to do option #2 :).

The only thing I could think of is if you have the camera in "AI FOCUS" mode (since I think that that mode automatically switches from single point AF to AI SERVO??

Is that the use case for option #2?

Also, can you let me know if I was correct in my guess that there isn't a way to set the starting point for "Zone AF" and "Zone AF Large"?

Thanks for the patience!

Jim

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