Setting up 7D for back-button-only autofocus

My 20D is giving up the ghost and I will be ordering a 7D in a week or two. I've been looking at a .PDF of the 7D manual and cannot quite figure out how to set up the 7D for back-button-only autofocus. I do not want the shutter release button to activate autofocus.

I understand that, unlike the 20D which has one setting to change, the 7D has two settings that need to be made for this functionality. Can anyone point me to the proper settings?

Thanks.

1) Menu
2) C.FN IV: Operation/Others
3) Item #1
4) Change AF-ON to Metering and AF Start (I think that's the default, though)
5) Change the shutter button to either Metering Start or AE lock. That will tell it not to use the shutter button for AF.

Thanks for the reply.

I guess I may not have made it clear that I want the shutter release button to activate auto exposure if I am not using manual mode but I want the AF ON button to be the only way to activate autofocus. Also, I don't want the AF-ON button to do anything but activate autofocus.

It appears that the setting you've selected in step 4 has the AF-ON button also activating auto exposure when pressed. Have I interpreted that correctly?

This is a good article on how to do this.

http://www.learn.usa.c​anon.com …ckbutton_af_art​icle.shtml

vorlon1 wrote in post #14225013
This is a good article on how to do this.

http://www.learn.usa.c​anon.com …ckbutton_af_art​icle.shtml

Thanks for the link.

SkipD wrote in post #14224988
Thanks for the reply.

I guess I may not have made it clear that I want the shutter release button to activate auto exposure if I am not using manual mode but I want the AF ON button to be the only way to activate autofocus. Also, I don't want the AF-ON button to do anything but activate autofocus.

It appears that the setting you've selected in step 4 has the AF-ON button also activating auto exposure when pressed. Have I interpreted that correctly?

When you go into the set-up menu and get into the shutter button half press menu one of the selections is "metering start" so you set the shutter to do that. Then you set the AF on button to AF and Metering Start. I do not see any choice on the menu for the AF start button that allows only auto focus. The choices are: Metering and AF start, AE Lock, AF stop, or FE Lock. So, mine is set to Metering and AF start, and I have the shutter button half press set to Metering start.

vorlon1 wrote in post #14225092
When you go into the set-up menu and get into the shutter button half press menu one of the selections is "metering start" so you set the shutter to do that. Then you set the AF on button to AF and Metering Start. I do not see any choice on the menu for the AF start button that allows only auto focus. The choices are: Metering and AF start, AE Lock, AF stop, or FE Lock. So, mine is set to Metering and AF start, and I have the shutter button half press set to Metering start.

Thanks a lot. Since I normally use manual exposure controls, that should work just fine. I only hope that the AF-ON button won't activate auto exposure if I elect to use one of the auto exposure modes.

I really like the total separation between using the shutter release button for auto exposure (if I use it) and the * button for autofocus on my 20D.

SkipD wrote in post #14225136
Thanks a lot. Since I normally use manual exposure controls, that should work just fine. I only hope that the AF-ON button won't activate auto exposure if I elect to use one of the auto exposure modes.

I really like the total separation between using the shutter release button for auto exposure (if I use it) and the * button for autofocus on my 20D.

Well, my guess is that when you focus using the back button and then let go of the button if you want to lock focus the metering would stop also, then the shutter button will take over with the metering when you press it. If you continue to hold down the back button for focus tracking in AI servo for a moving subject then I guess the metering would stay on, but I;m not sure if it would be causing any issues because you would be initiating metering anyway with the shutter button.

SkipD wrote in post #14225136
Thanks a lot. Since I normally use manual exposure controls, that should work just fine. I only hope that the AF-ON button won't activate auto exposure if I elect to use one of the auto exposure modes.

I really like the total separation between using the shutter release button for auto exposure (if I use it) and the * button for autofocus on my 20D.

Hi Skip,

Not to worry... it will be the same in any of the "Creative" modes (as Canon calls them: M, Tv, Av, P). BBF won't "force" AE when you don't want it and have the camera set to M. It will merely start the metering, just the same as if you didn't have BBF set up.

To clarify a little... essentially it's a two or three step process setting up BBF on 7D.

First thing though... be aware that you can assign to either the AF-On button or to the * AE Lock button. Your choice. (Personally I use the * button because it's bigger, more prominent and closer to my thumb... But also because I still have and use some older models that don't have the AF-On button and have to use the * button, so this is the most consistent setup for me. If you are keeping your 20D and want to use it as backup, you might want to use the * button on both.)

As mentioned above, go to Custom Function IV-1. This allows you to assign functions to a number of different buttons on the camera. On 7D, when you call up that C.Fn you'll see a summary of all the configurable buttons. Press the Set button and the first button will be shown in detail and happens to be the Shutter Release button, half-press. Press Set again and you'll see the three choices for that button. Choose the center one (looks like the metering icon) to turn off AF and only have metering (and IS) done by the shutter release button, half-press. The third choice is the same, plus AE Lock. I don't recommend having AE Lock on all the time, though. There are too many situations where you don't want AE Lock to happen. And, you'll still have it available at the press of another button.

If you plan to use the * button for Back Button Focusing, you'll need to do two more steps. If still in the Shutter Release Button setup panel, press Set again to back out of that and use the Back Dial to navigate to the AF-On button, press Set to enter the setup panel and change it to the second choice, which is * (AE Lock). Once that's done, pressing Set one more time to get back to the overall display. Use the Back Dial again to navigate to the * Button panel, press Set to enter the setup panel and change it to the second choice, which is "Metering and AF start". Press Set again to save the setting and go back to the main Custom Control display.

You're done setting up focus and have one last thing to do. You actually will get metering (and IS) start with both the shutter release button, half-press and with the * button. So it's not a concern. AF will only operate when the * button is pressed. One Shot and AI Servo will work as usual.

The last thing you need to do if setting up to use the * button for back button focusing is to go into the AF-On button setup panel and change it so that it will perform * AE Lock. It's the second choice on that panel.

Alternatively, if you prefer to use the AF-On button to control Back Button Focusing, it's even easier. First do step 1 above, then just go into the AF-On button setup panel and check to be sure it's set up on the first choice, which is Metering and AF start. It should be by default, so this is just to double check.

So, to summarize, in the first case you have unassigned AF from the shutter button, reassigned it to the * button, and then also reassigned the AF-On button to do AE Lock.

In the second case, you've unassigned AF from the shutter button and checked to be sure it's assigned to the AF-On button (and left AE Lock alone, at it's default assigned button).

I mentioned in passing above, Image Stabilization will start along with metering, so IS also will start with both half-press of the shutter release and pressing whichever back button you chose to use.

Thanks much, Alan. I appreciate the info.

You can also access the button customization screen by pressing the Q button and navigating to the picture of the back of the camera. Easier, IMO.

Higgs Boson wrote in post #14225653
You can also access the button customization screen by pressing the Q button and navigating to the picture of the back of the camera. Easier, IMO.

Good info. Thanks.

I've used this method for years for sports and wildlife.