7D Markll custom back button focus

I assume I can do this. Can I set the AF-ON button to us AIServo to follow my subject and snap my shot with the shutter button and then have single shot work as normal by pressing the shutter button half way to compose and then press all the way to take the shot. If I have someone else take a shot of say my wife and I when on vacation, I think it is easier for someone not familiar with the whole back button thing to take the shot. Seems like it should be no problem but I didn't know if having the shutter button set to compose a shot in single shot would mess up the back button focus. Any special setting I need to use?

AF/ON button is ON from factory. What you really need to do is remove FOCUS from the Shutter

Nascar Nut wrote in post #17973037
I assume I can do this. Can I set the AF-ON button to us AIServo to follow my subject and snap my shot with the shutter button and then have single shot work as normal by pressing the shutter button half way to compose and then press all the way to take the shot. If I have someone else take a shot of say my wife and I when on vacation, I think it is easier for someone not familiar with the whole back button thing to take the shot. Seems like it should be no problem but I didn't know if having the shutter button set to compose a shot in single shot would mess up the back button focus. Any special setting I need to use?

The button cannot Focus AND not focus at the same time; Schroedinger's Camera isn't really a thing You're talking about separate functions that just happen to inhabit the same control [which is something that drives me nuts, anyay; thanks Canon]. One Shot, AI, AI Servo are AF functions and are controlled by whichever button(s) are configured to AF Start/Stop; but you cannot configure one button to AF with One Shot and another one to do so with Servo.

You'd have to do this by registering a Custom (C1, C2, C3) setup with the settings you'd want (or just change the dial to 'P') if you are handing if off to someone else.

you can customize the camera controls so that the af-on button switches from one shot to servo, but you have to hold that button down for the switch to work. so if you're in one shot mode normally, it'll switch to ai servo and vice versa. it does nothing in ai focus.

the one shot<->ai servo customization also doesn't actually start focus--all it's doing is switching from one shot to servo or the other way around. you have to keep the af and metering on the shutter for it to work correctly.

edit: pg 446-447 in the 7d mk ii manual shows which buttons can be set to do the one shot<-->ai servo, so it's not just the af-on button, if you want to use a different button for that instead.

So the reason I posted this is, when you set the shutter button half press to metering and AF start that it won't mess with my AF-ON button that is set to metering and AF start AI servo. So now when I push and hold the AF-ON button and track my moving subject and now push the shutter button to take the photo while still holding the AF-ON button, does the shutter button try to focus before taking the shot? Hope that made sense.

Snydremark wrote in post #17973086
The button cannot Focus AND not focus at the same time; Schroedinger's Camera isn't really a thing ...

You seem to fundamentally misunderstand Erwin's thought experiment. The button really can focus and NOT focus at the same time. The problem here is the experimenter (shooter) forces the reality by participating in the experiment (pressing either button). Upon selecting and pressing a button, the shooter moves from the quantum world to the macro world, where one or the other realities must take place. Reality is dictated by the settings chosen on the camera.

For example, I have my "*" button programmed to annihilate the Andromeda galaxy in an matter/antimatter collision. Alas, that is only in the realm of possibility. Once I force reality by actually pressing the button, my camera does the usual exposure lock.

Ok, Scotty. I'm done here. You can beam me up, now.

Archibald wrote in post #17972252
Great Egret in a stretch.

Nascar Nut wrote in post #17973613
So the reason I posted this is, when you set the shutter button half press to metering and AF start that it won't mess with my AF-ON button that is set to metering and AF start AI servo. So now when I push and hold the AF-ON button and track my moving subject and now push the shutter button to take the photo while still holding the AF-ON button, does the shutter button try to focus before taking the shot? Hope that made sense.

Since you are still pushing the af-on button the Camera continues to focus and the BBF attributes (AI Servo in your case with whatever parameters) is over riding the AF parameters on the shutter button. So yes this will work. But one of the nice things about BBF you are losing and that is the ability to stop focus if you keep it on the Shutter as well.

As was me mentioned, it is better to use one of the Custom C1 C2 C3 buttons for with you or someone else.

Nascar Nut wrote in post #17973613
So the reason I posted this is, when you set the shutter button half press to metering and AF start that it won't mess with my AF-ON button that is set to metering and AF start AI servo. So now when I push and hold the AF-ON button and track my moving subject and now push the shutter button to take the photo while still holding the AF-ON button, does the shutter button try to focus before taking the shot? Hope that made sense.

Think of it this way. The shutter button is, by default, acting as two, distinct buttons. Button 1 is "Metering and AF Start" for a half press (this is the function you can remap) AND shutter release, which you cannot change. So, when you set "Metering and AF Start" on any button, it is doing the exact same thing as a half-press of the shutter button; which is engaging whichever AF function you have set on the camera. So, you *can* have both buttons set to "Metering and AF Start" and if you are using one (say the AF-ON button) and then engage the other one, the camera knows it's already trying to focus and doesn't "try again".

HOWEVER, The buttons cannot be set to control separate AF functions. Both buttons will still be triggering AI Servo if that is the AF mode you currently have selected; so this, "set the AF-ON button to us AIServo to follow my subject and snap my shot with the shutter button and then have single shot work as normal by pressing the shutter button half way to compose and then press all the way to take the shot", is not possible.

To get around that, when you think you're going to be in situations where you want to hand your camera to a non-photographer, you can:
A. Set the camera to 'P' mode and have them take the snapshot
B. Define a custom setting (C1, C2, C3) with the AF setting active that you want [In this case, One Shot AF); this one would also require that you evaluate where you are and lock in your metering, too. Otherwise, this would be a lot of work to achieve A, above.
C. Map another button, like the DoF preview button to toggle One Shot/Servo when pressed; leave the camera set to One Shot AF and then hold that while you're doing your own shooting. That way, when someone else picks up the camerra, it will function in One Shot. I say the DoF preview button simply because, on the 7D!!, they moved it to a location that is pretty easy to access/use, finally. It's quite easy to reach with your ring finger when holding the camera normally.

Does that (wall '0 text) help?

Bassat wrote in post #17973638
You seem to fundamentally misunderstand Erwin's thought experiment. The button really can focus and NOT focus at the same time. The problem here is the experimenter (shooter) forces the reality by participating in the experiment (pressing either button). Upon selecting and pressing a button, the shooter moves from the quantum world to the macro world, where one or the other realities must take place. Reality is dictated by the settings chosen on the camera.

For example, I have my "*" button programmed to annihilate the Andromeda galaxy in an matter/antimatter collision. Alas, that is only in the realm of possibility. Once I force reality by actually pressing the button, my camera does the usual exposure lock.

Ok, Scotty. I'm done here. You can beam me up, now.

Also, I hate you well played sir

If I am reading this correctly then I have what you want set up using the * button.
Camera is in one shot focus mode with focus on the shutter button. Holding in the * button switches the camera to AI servo focus mode. Nothing else changes. This can be done with the AF-ON button also. It just toggles the focus mode and it works in both directions. Camera in servo and pressing the * button switches to one shot focus mode.

My camera is always in continuous shooting mode anyway so I don't need to configure it but you can with either of the two buttons mentioned above.

In your scenario, hand the camera to someone else and all works as expected with the shutter button but you have AI servo focus under your thumb.

Rod

Snydremark wrote in post #17973737
Also, I hate you well played sir

Likewise, I am sure.

Care to go down the 'size' of a blackhole blackhole?

yeah, you can't have the af-on button (or any other control, really) specifically start af as ai servo, but like Snydremark was saying, you can have both the af-on and the shutter set to do af start and metering, and use the dof button to switch between one shot and ai servo. that way, you can use the af-on button to do back button focus, and novice camera users can use the shutter to focus as well. you can leave your camera in one shot mode and hold the dof button when you want to switch to ai servo.

again, there is no button that starts ai servo af by itself. this is probably the only way to accomplish what you're trying to do.

Ok, set up my camera with the AF-On button set to AI Servo and the shutter button set up as normal. Now when I want to shoot in one shot mode, I use the shutter button. Say a bird on a nest, I take its picture. Now the bird takes to flight so I push and hold the AF-On button to follow the bird and press the shutter button to take the picture. Not sure about the post above saying I can't start Ai servo with this button. If you hit the info button while in that setting it is right there. The only thing I don't see is for continuous shooting mode. I don't leave my camera in this mode as I end up taking a bunch more pics when I am just shooting in single shot. Is there a way to add continuous shooting mode to the AF-On button?

Nascar Nut wrote in post #17974097
Ok, set up my camera with the AF-On button set to AI Servo and the shutter button set up as normal. Now when I want to shoot in one shot mode, I use the shutter button. Say a bird on a nest, I take its picture. Now the bird takes to flight so I push and hold the AF-On button to follow the bird and press the shutter button to take the picture. Not sure about the post above saying I can't start Ai servo with this button. If you hit the info button while in that setting it is right there. The only thing I don't see is for continuous shooting mode. I don't leave my camera in this mode as I end up taking a bunch more pics when I am just shooting in single shot. Is there a way to add continuous shooting mode to the AF-On button?

How do you have one button doing Servo and one button doing One Shot? Or are you doing what Rod said where you're setting AF-ON to enable Servo while you're holding it but actually activating AF via half press of the shutter button?

Maybe I am not doing it right but here is what I did. Go to custom controls and select AF-ON and hit the set button. Set that to metering and AF start and then hit the info button. Now go to AF operation and select AI Servo. Now set up the shutter button for one shot same way.