AF-ON button related Custom Functions.

Hi,

lately I've been using the AF-ON, Back-button-focussing-button or whatever you want to call it, on my newly acquired 40D (which is an awesome camera btw.)

Now, there's two pretty important CfN concerning the Af-on button.
CfNIII-2 and CfNIV-1.
The thing is this:
I've set CfNIV-1 to 2: Metering start/Meter+Af start.
This means my shutter button is only used for metering and my Af-on button for focusing. I find it much more convenient.

Now, onto CfNIII-2; this functions lets you control what the AF-on button is used for. Currently I've set it to zero: Af stop, but would it even be possible to let it do something else? Personally, I would to use the One Shot <-> Ai Servo mode, but if I'd use that functions, wouldn't the camera be ALWAYS using Ai Servo mode, because I'm pressing the Af-on button for focusing? Is there any way around this?

What do you guys 'n gals use as combination between these two settings and why so?

EDIT: One more thing. When choosing the One Shot <-> Ai Servo mode, the display doesn't change when triggering the function right? It will still read One Shot even though you triggered it and the actual Af mode is Ai Servo?

Regards from Amsterdam

How is your camera going to use the AF-On button to focus when you have it set to stop AF?

Fligi7 wrote in post #12585815
How is your camera going to use the AF-On button to focus when you have it set to stop AF?

That's what I wondered too, but apparently the one function overrides the other, thus AF'ing but not using the stop-Af.

If you want to use your AF-ON button for something else, you can swap your * and AF-ON buttons so that back-button focus is assigned to * and AF-ON can be assigned to something else. Which function does that and what options you have will vary, but will be in your manual.

CFnIII-2 dictates functionality of the "AF Stop" button that is present on some super telephoto lenses. It doesn't do anything except muck up your camera function if you inadvertently set it to "5: IS start". Selecting this setting, with any other lenses, will cause your IS system to never engage.

Do yourself a favor, set that back to '0' and forget that custom function exists until you slap a 400mmL f/2.8 or such on there that has that button

Snydremark wrote in post #12587205
CFnIII-2 dictates functionality of the "AF Stop" button that is present on some super telephoto lenses. It doesn't do anything except muck up your camera function if you inadvertently set it to "5: IS start". Selecting this setting, with any other lenses, will cause your IS system to never engage.

Do yourself a favor, set that back to '0' and forget that custom function exists until you slap a 400mmL f/2.8 or such on there that has that button

I know, but it's like this: I want to assign two different functions to the Af-on button:
- Focusing (like I have it now) and no focusing on the shutter button
- Ai Servo <-> One shot mode

It seems like it isn't possible to allocate both functions to the same button...

Fligi7 wrote in post #12587175
If you want to use your AF-ON button for something else, you can swap your * and AF-ON buttons so that back-button focus is assigned to * and AF-ON can be assigned to something else. Which function does that and what options you have will vary, but will be in your manual.

Yeah but that still doesn't solve the problem.

As far as I know, you can't assign two different functions to the AF-ON button. If you could, you wouldn't be able to currently use your AF-ON button since it's programmed to focus and also not focus at the same time.

Fligi7 wrote in post #12587344
As far as I know, you can't assign two different functions to the AF-ON button. If you could, you wouldn't be able to currently use your AF-ON button since it's programmed to focus and also not focus at the same time.

Yeah, but that would be two options in the same setting.

I'm talking the focusing function ánd the Ai servo <-> One shot on the same button.
Switching the '*' with the Af-on button doesn't matter...

TijmenDal wrote in post #12587277
It seems like it isn't possible to allocate both functions to the same button...

Fligi7 wrote in post #12587344
As far as I know, you can't assign two different functions to the AF-ON button. If you could, you wouldn't be able to currently use your AF-ON button since it's programmed to focus and also not focus at the same time.

TijmenDal wrote in post #12587532
Yeah, but that would be two options in the same setting.

I'm talking the focusing function ánd the Ai servo <-> One shot on the same button.
Switching the '*' with the Af-on button doesn't matter...

I thought that's what I just answered. You've lost me now.

TijmenDal wrote in post #12587277
I know, but it's like this: I want to assign two different functions to the Af-on button:
- Focusing (like I have it now) and no focusing on the shutter button
- Ai Servo <-> One shot mode

It seems like it isn't possible to allocate both functions to the same button...
...

This is correct; what you are trying to do is not possible. Period.

What is the problem you're trying to solve?

Snydremark wrote in post #12587656
This is correct; what you are trying to do is not possible. Period.

What is the problem you're trying to solve?

Which of the two should I choose?

And when using Ai Servo <-> One shot mode, is it true that on the top lcd it doesn't change, even when pressing the Af-on button (with that option assigned to it, and the focus mode not)?

It was already stated above that you are looking at the wrong custom function. The one that offers a switch between One Shot AF and Servo AF is not related to the AF-ON button, but the AF stop button. It's a button which is present on some expensive lenses. So to use that you need such a lens, or a 7D (a cheaper way).

You can't use it. You don't have the gear for it, until you purchase an EF 300 mm f/2.8L IS II USM or similar.

And yes, the display does indicate the focus mode being used.

Snydremark wrote in post #12587656
This is correct; what you are trying to do is not possible. Period.

What is the problem you're trying to solve?

apersson850 wrote in post #12591068
It was already stated above that you are looking at the wrong custom function. The one that offers a switch between One Shot AF and Servo AF is not related to the AF-ON button, but the AF stop button. It's a button which is present on some expensive lenses. So to use that you need such a lens, or a 7D (a cheaper way).

You can't use it. You don't have the gear for it, until you purchase an EF 300 mm f/2.8L IS II USM or similar.

And yes, the display does indicate the focus mode being used.

Oh! But, as I'm not using sick telephoto lenses it doesn't show. Ok, never mind.
I guess this can be closed now. Sorry, that was really stupid.

Not stupid, just confused So, what's the problem you were trying to solve? Just an easier way to toggle between One Shot and AI Servo modes?

I would love to be able to switch the "AF-ON" button to One Shot -> Servo... Would be so nice. And not like the 7D where it switches only when held down, but instantly switch the function all together. Would be great!

I guess in the 5D2 it would have to be a function for the * button, and then switch the button function over to the AF-ON button... I would love that though.