Problem using 50D back button focus with vertical grip

I just bought a battery grip for my 50D. I have my AF set up for the back button, and only use AI Servo and the back button - no reason to focus any other way, for what I shoot.

So, I installed the battery grip. This is the original Canon grip, not a 3rd party version. I notice it has the shutter button and the two other buttons, but it appears to be missing the "AF on/off" button, which is what I use to focus with.

So my question is, how does one use back button focus using the vertical grip's controls? If this is simply not possible, the grip is practically useless to me.

Any help or advice would be greatly appreciated.

Use the * button.

I was going to suggest that you set the Custom Function to use the * button for BBF - thats what we use on models that don't have the AF-ON button. In the 50D manual I see you can swap the AF-ON and * button with another custom function.

However, that would change it on the grip and on the body. You probably don't want that.

Don't know how you can change it on the grip and not on the body.

I did not realize that custom functions allowed the back button focus to be assigned to any button other than the AF on/off button.

When I made if able to back button focus, I just got on YouTube and did what the guy said to do in the custom functions. Nothing was ever mentioned about having different options.

I'll have to see if there's a video that shows how to re-assign the back button function to a different button.

This should be it. C.Fn IV-1 - whats your set to now? With C.Fn IV-2 you can switch whatever AF-ON did to the * button.

runninmann wrote in post #15113362
Use the * button.

...but then you lose a convenient way to lock exposure, since that button is no longer available. Gotta wonder why Canon didn't put both buttons on the grip!

Wilt wrote in post #15114051
...but then you lose a convenient way to lock exposure, since that button is no longer available. Gotta wonder why Canon didn't put both buttons on the grip!

No way to lock exposure - oh, this is frustrating!

I guess if I re-assign the function of the asterisk button to that of the AF on/off button, then I will simply have to shoot in Manual all the time, or my images will be all messed up, exposure-wise. That is unfortunate, as there are situations in which I really do rely on Av mode.

Tom Reichner wrote in post #15114095
No way to lock exposure - oh, this is frustrating!

When you activate the previously mentioned custom function that switches the AF-ON and * buttons...well, the functions just get switched, so the AF-ON button becomes your exposure lock button. It does mean you won't have an exposure lock button on the vertical grip, but at least you'll always have one on the main body.

If that isn't satisfactory for you, could also remap the C1 and C2 positions on the mode dial. That'll let you quickly change control layouts...though there are other limitations with doing that. I agree that the BG-2N should've had the third button.