What is Back Button Focus all about?

Started Mar 25, 2014 | Discussions thread
enemjii Senior Member • Posts: 1,889
Re: What is Back Button Focus all about?

enemjii wrote:

Phhoenyxx wrote:

Phhoenyxx wrote:

enemjii wrote:

I read through the postings and I figured it is a Focus lock button. Did I get that right?

No, it's an autofocus triggering button. If you want it to lock focus you set the camera to AI Servo and lift off when you want to lock focus, and back on again when you want autofocus to go again. Try it!

Does it need to be on AI Servo?

No it doesn't need to be, but if it's in One-shot that will lock the focus on the subject for you, rather than you lifting off the button. So you see how it's not a subject-in-focus lock-by-lifting-off button unless you're in Servo?

I thought that as soon as you let go, it is essentially locked because it doesn't refocus, so you can take as many shots as you like without pressing it again.

In One-shot it will do that if you don'tlet go. Try it!

In One-Shot, you keep pressing until it achieves focus. Once it achieves focus and you let go of the button, what happens? Does it somehow lose that focus?

Only if you press it again. (But you knew that because you tried it, right?) That's why it's an autofocus triggering button, not an autofocus locking button. You don't generally define the function of something by what it doesn't do when you don't use it.

Whaaaa... That is just semantics. It is a focus lock button. A rose is still a rose....

Let me refine it... It is a focal length lock button.

The only way to lock the focal length  is to let go of the zoom.........or use a prime. Wilba and others are not using semantics,they're telling it as it is.

So back button focus is how you use it. But what is it?

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