EOS 6D Mark II Thoroughly confused on back button focus (yes, I read the manual!)

[Skip70]

Yes, I believe the first step is to carefully read the manual, and I've done that several times. I must have taken my dumb pill this morning, but I need some hep and hope someone here can offer that. 

I have already "removed" AF from the shutter button. 

I'll start with what I['m tryin to set as a capability:

• press and release the AF On button to hold focus as I hit multiple shutter clicks  
• be able to hold the AF Botton while in Serco mode. 

What I don't understand is how to assign both functions to that button. I don't understand what AF Start and Stop means,, but I also don't understand how to assign those two functions on the button. If I select one, it shows on the menu, but if I then pick the other, the first one is replaced. 

Help, please? 

[stevet1]

Skip70,

I read this on another website concerning the AF-STOP or AF-OFF function:

- QUOTE -

"According to Canon's Lens Performance page, this button is intended as a way to temporarily disable the autofocus, for example if you see that an object is about to pass in front of the lens that's not on the same plane as your primary subject. Thus, focus is retained (or close to retained, with a moving subject) while the obstruction passes, and autofocus can be resumed from a good starting point once it's gone.

Edit: Note, also, that the AF Stop functionality can also be achieved through other buttons on some cameras, via Custom Function settings, by setting a button (e.g. the * button) to "AF-OFF". (Thank you @caleb, for that information.)

- ENDQUOTE -

Steve Thomas

[p4pictures]

Ok step by step.

Press MENU button and navigate to the Custom function menu tab, then navigate to C.Fn III-4 Custom controls and press SET.

You'll see a list of the buttons that can be reconfigured. The one you need to change is the shutter button to stop it initiating AF at the half-press stage of its travel. The full-press will always fire the shutter. Select the shutter button, the first icon on the left, and press SET. You should see that it is set to Metering and AF start as that is the default. For back button you need to change this to either metering start or AE-Lock (while button is pressed)

If you choose metering start option - the camera will meter the exposure for each frame in a sequence, so you might see different exposure values for each or some of the frames in a sequence. As an example, if you photograph a horse as it runs from open field to under a tree and out the other side in to the sun, this option adjusts the exposure between the brighter sunny open section and the frames under the tree in the shade.  

If you choose AE-Lock then the exposure is measured and locked for the first frame of the series while you press the shutter. If you release the shutter fully, and then re-press it the camera meters again. This option is for when you want the same exposure, so if you metered from the face of a player and they run towards you in the same light then the exposure would be consistent for the face for all the shots in the sequence. 

If you use manual exposure mode M on the dial and set the shutter speed, aperture and ISO values yourself, then both options above will give the same results. For other modes like P/Av/Tv they work as described above, and also for M with AUTO ISO.

Once you set the shutter button, just move to the AF-ON button and check that it is set to the default Metering and AF start.

[Tronhard]

This was sorted a while back.  OP is all good now

[Skip70]

These cameras are endowed with so much functionality it can bewildering! Paradox Of Choice writ large.