40D custom Functions IV "AF-ON"

[Julian H]

Just upgraded to a 40D and despite doing some browsing, can't seem to get my custom functions set the way I'd like.

Here's my wish:

To be able to switch AF from the shutter to the "AF-ON" button.
If I keep this depressed, the "AF-ON" switch behaves like AI Servo basically. Shutter takes the picture.

When I let go of the "AF-ON", I'd like AF to lock on my subject, allowing me to recompose and depress the shutter to take the shot.

This way I get to use both AI Servo and "one shot" focussing without the hassle of switching the modes via the dials.

I know this can be done on other models, yet despite some trying, I cna't seem to get it to work?

Anyone configured their camera's CF buttons to achieve this, and if so, a detailed list of the settinngs would be good.

Thanks in advance,

Julian

[Roy C]

Just upgraded to a 40D and despite doing some browsing, can't seem to get my custom functions set the way I'd like.

Here's my wish:

To be able to switch AF from the shutter to the "AF-ON" button.
If I keep this depressed, the "AF-ON" switch behaves like AI Servo basically. Shutter takes the picture.

When I let go of the "AF-ON", I'd like AF to lock on my subject, allowing me to recompose and depress the shutter to take the shot.

This way I get to use both AI Servo and "one shot" focussing without the hassle of switching the modes via the dials.

I know this can be done on other models, yet despite some trying, I cna't seem to get it to work?

Anyone configured their camera's CF buttons to achieve this, and if so, a detailed list of the settinngs would be good.

Thanks in advance,

Julian
Hi Julian, I have this set-up and use it all the time for birds.
Enable the custom function C.Fn IV-1 in the set-up menu I use option 2.

set the lens to AF and the camera to AI servo and providing you have a full time manual focusing lens you have the best of all worlds:
a) Keep your thumb on the button and you have AI servo
b) Hit the button and release and you have a one-shot AF
c) by not touching the AF on button you have manual focusing.

Hope this helps.

[Julian H]

Roy,

Thanks for that! I'll give it a whirl..

best,

J

[Mahsleb]

Hi Julian, I have this set-up and use it all the time for birds.
Enable the custom function C.Fn IV-1 in the set-up menu I use option 2.

set the lens to AF and the camera to AI servo and providing you have a full time manual focusing lens you have the best of all worlds:
a) Keep your thumb on the button and you have AI servo
b) Hit the button and release and you have a one-shot AF
c) by not touching the AF on button you have manual focusing.

Hope this helps.

Thanks Roy this has helped me too :t:
While in for repair my camera got reset to default
and I couldn't remember how to set it back again

Cheers

[Tannin]

There are quite a few ways to set up the AF on Canon cameras, just in case anyone is reading this thread and pondering what will suit them best, there is a third good alternative.

If you've tried back-button focus and see some advantage to it but, on balance, dislike not having auto-focus available on the shutter button, try [i]reverse back-button focus[/b]. Through the same custom function menu, you can set the back button to act as an auto-focus STOP. You AF as usual with a half-press, but whenever you want to freeze the focus and reframe (or freeze it for any other purpose) you simply squeeze with your thumb. For example, focus on the eye, squeeze, then reframe and shoot. When you want to go back to normal auto-focus, just let go. The same applies if you want manual focus for a moment: you return to normal auto-focus mode as soon as you lift your thumb.

(Which is the best method of controlling focus? None of the above, or all of them - just whichever way suits you best. Try all three and decide for yourself.)

(Sorry for going a little off-topic.)