Canon 7D ~ AF settings

Yes, I've googled it, RTFM and searched PotN... I just can't find a straight and simple answer!

On my 20D and 30Ds, I have the multi-point controller set to select my single focus point. I then use the * to focus lock and half-shutter for exposure-lock. I like it this way, and it's been like that since day-one.

I've now got the 7D set-up the same way.

But, I'd like the AF-on button to enable AI Servo focussing - is this possible?

What can I do with the AF-ON button that will help me day-to-day? Just looking for some help.

Also, I always use a single AF point. Should I use expanded focus points to gain better focus-lock - at the expense of focus inaccuracies?

The AF-ON button can't do that. The DOF button can, though, as long as you keep it pressed.

You can have the AF-ON focus with the selected point and the * button focus with the Home Point, for example. If you still need AE Lock, you can move that to M.Fn.

Cool, I'll set the DOF button to do that then, great.

What's HP exactly, I don't quite get it!? Would that be the centre focus point, or a pre-determined 'default' AF point?

HP is Canon's abbreviation for "Home Point". An AF point you register at some location where you want it. You can then for example set a button to always focus with that registered Home Point (HP), regardless of where you have moved around the selected AF point.
You can also set the multi controller (joystick) to select either the center or the home point when your press the multi controller, instead of tilting it.
You can register different Home Points for different orientations, if you have that function enabled.

Cool, I'll have a look in the manual for where I set the Home Point, and for where you make it selectable with the correct button.

I presume you could set the AF-ON button to focus using the HP and the * button to focus using the selected focus-point?

Yes, you can. And if you then still want to keep AE lock available, you can move that out to the M.Fn button.
Or if you want to do it in another way, you can focus with selected point with half-press of the trigger and with home point using AF-ON. Then AE lock can remain with the * button.
Look at the detailed description of C.Fn IV-1 for all the info you need.

I have AE Lock on half-press shutter.

That's one other option. But if you still want to have the ability to track a subject, which is lit differently as it moves (in and out of shadows, for example), my suggestion is better.

dof button is clumsy and out of the way I really liked having the af button as the on off. You can use it to turn servo off though. So that is backwards from prior. a half press of the shutter turns it back on so that is another option.

Hmmm, lots to mull over! I'll try them all out over the weekend and decide what's best for me.

dashotgun wrote in post #9001346
You can use it to turn servo off though. So that is backwards from prior.

You can also use Servo AF all the time, but just execute when AF-ON is pressed. Kind of converts it to One Shot, with the drawback of less sensitivity at low light.

Ah, that's interesting. So AF-ON could activate SERVO and * be One Shot?

sando wrote in post #9001674
Ah, that's interesting. So AF-ON could activate SERVO and * be One Shot?

I think what he meant was you can emulate One Shot by using AF-ON (or "*") button for AF start/stop since you have that separated from the shutter. All you have to do is let go of the AF-On button when you achieved the desired focus...

But then there's no focus confirmation beep, flash of red light, or green light. Shame.

sando wrote in post #9001887
But then there's no focus confirmation beep, flash of red light, or green light. Shame.

Why is that a shame?
The camera is continuously focusing in servo mode. Why would there be a beep or other confirmation mechanism in servo mode?