Back Button Focus Question

THis is probably so simple I'll feel like a moron for asking, but once you set your camera'a custom fn for bb focusing, is it always on or do you have to press the AF on button (or the other, if you've switched the button fn like I have) to turn it on?

Is what always on?

krb wrote in post #9639844
Is what always on?

Is the back button focus always on, operational?

I'm still not sure I understand. If the button is set to do AF (and the camera is turned on) then it will do AF when you press it and stop doing AF when you release it, just like when the shutter button half-press is used for AF.

Michelle Brooks Photography wrote in post #9639834
THis is probably so simple I'll feel like a moron for asking, but once you set your camera'a custom fn for bb focusing, is it always on or do you have to press the AF on button (or the other, if you've switched the button fn like I have) to turn it on?

Focus and Is only on (working) when you press the button, when you remove your finger it will stop focusing.


Krb: in before me.

As dumb as it sounds, that is exactly what I was wanting to know...don't judge me!
Thanks guys!

Oh wait, I forgot to mention I Manual focus...how does that mix in? NO difference? Redundant?

If you manual focus (and have back button enabled), just don't push the AF-ON button and the camera won't autofocus at all.

If the lens is set to MF, it won't matter what you do since only turning the focusing ring will focus the lens.

And even if you've set the AF to the * (or AF-ON, depending on your camera), when you put the camera into one of the "Basic" modes, AF will revert to the shutter release.

If you manual focus, best bet is to set the lens to MF, that way there is no chance of an inadvertant button press screwing up focus.

Veemac wrote in post #9639969
If you manual focus (and have back button enabled), just don't push the AF-ON button and the camera won't autofocus at all.

Jon wrote in post #9639992
If the lens is set to MF, it won't matter what you do since only turning the focusing ring will focus the lens.

And even if you've set the AF to the * (or AF-ON, depending on your camera), when you put the camera into one of the "Basic" modes, AF will revert to the shutter release.

I never shoot in one of the auto (basic) modes, so I don't have to worry about that. And I always keep my lens in MF. So--is there even any reason for me to use the BB method in conjunction with MF? Sorry if I'm confusing the issue. I've only been practicing this BB method a little bit--from memory, I think what i do is, in MF, I press the * button (which I switched with the AF On button) and while pressing it, focus manually until I get my little beep then let off the * button.

If you have lenses with full-time manual, you can leave the lens in AF mode and manual focus when you like. Just don't press the AF On or * button, whichever AF is set to. The focus confirm light/beep won't go on, though...but you shouldnt be using that as a focusing guide with an AF lens. You aren't getting any more accurate results.

Michelle Brooks Photography wrote in post #9640209
I never shoot in one of the auto (basic) modes, so I don't have to worry about that. And I always keep my lens in MF. So--is there even any reason for me to use the BB method in conjunction with MF? Sorry if I'm confusing the issue. I've only been practicing this BB method a little bit--from memory, I think what i do is, in MF, I press the * button (which I switched with the AF On button) and while pressing it, focus manually until I get my little beep then let off the * button.

Yeah, that will work. But if you're going to rely on the camera to tell you when you're in focus, why not let it move the lens, too.

If you are in AI Servo, it will continue to focus as long as you hold down the AF-On (or *) button, and cease focusing when you release it.

If you are in One Shot, it will start to focus when you press the back button, and cease when it acquires focus.

If your lens switch is set for MF, then your back button will do nothing when you press it. If your lens has full time MF, it will override the AF just like it would with shutter button focusing.

toxic wrote in post #9640242
If you have lenses with full-time manual, you can leave the lens in AF mode and manual focus when you like. Just don't press the AF On or * button, whichever AF is set to. The focus confirm light/beep won't go on, though...but you shouldnt be using that as a focusing guide with an AF lens. You aren't getting any more accurate results.

Question-- if you aren't looking for the confirmation light/beep to tell you when you've achieved focus, are you just going by when it looks to be in focus?