What is Back Button Focus all about?
Here it is - All said and done, the button activates focusing, instead of the shutter button. If you do not press the back button, it will continue to shoot at the focus distance that was shot last, in effect, providing you with a focus distance lock.
You can use back button focusing to solve this problem because the distance between the photographer and the subject stays the same between both shots, but the composition changes. With back button focusing, the photographer activates focus for the first shot, and then is able to recompose infinite times as long as the distance between the camera and the subject remains exactly the same.
my focus would have been locked on the wolf still and I could have shot to the side of the photographer and still got sharp shots as soon as I shewed him out of the frame.
I see we went full circle as this info was provided in the 2nd post by Scorpio a week ago..........
I am easily amused, at times, Mike
The above sentence was what I was referring to. The thread was informative, and valuable. To come full circle in less than a week was amusing to me.
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"Five out of four people have trouble with fractions."
Hey, I am glad we amused you rather than abuse you!
I am glad you stayed with us while we fumbled through this and understood the BBF concept.
All said and done, I personally believe thus is the wrong term to use. If I put that same button on the front of the camera doing exactly the same thing, I would have to call it FBF?
I'll just mention this. IMO the design of the two upper-right backside buttons (the AF-point & "back button AF" button) is tremendously improved in the newer Rebel bodies (T5i/T4i) over the T2i. I have both the T2i & T5i at the moment.
The T2i buttons are spongy and recessed. A PITA to use IMO, and frustratingly regressed from even-older bodies (XSi).
The T5i buttons are prominent and have a good pop when pressed. Huge improvement IMO.
Note that I'm just talking about the 2 upper-right buttons. Almost every other button feels worse on the T5i IMO, but that's another subject...
Thought I would present this. I have the Sony A65 and it has a button on the front left side of the camera (looking from your side) that when pressed will hold the focus (distance) which you achieved when you half pressed the shutter button. After that you can click as many times as you want and it will continue to capture at that distance as long as you keep clicking and do not let go of that button.