I rented a Nikon D810 over the weekend. The camera was setup for focus and recompose- that is the focus function was disabled for the shutter-release button and enabled for the AF-ON button. This technique worked fine as long as there was little delay between focusing and recomposing. Many times a longer delay (10 seconds?) was required, and then the shutter-release button would not work until I re-focused. Does this sound right? Any comments?
In AF-S Mode keeping the AF-ON button pressed while recomposing and releasing should work.
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Best Regard
EMs1950
But if he holds down the AF-On button while recomposing then his focus point will change from what he had originally intended.
Ed
Not in AF-S mode. Pressing an holding AF-ON locks the focus.
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Best Regard
EMs1950
Oh, I see your point. I have my camera configured so that pressing AF-On activates the focusing instead of using a half shutter button press. Then when I release the AF-On button the focusing stops and isn't activated when I press the shutter release.
So many choices. :-D
Ed
On second thought, I don't see your point. AF-On always initiates focus. I think you're thinking of AF-L(ock).
Ed
He is correct. The problem with the OP's post is he is not specific about how the camera is set up. All he says is that supposedly the AF-ON button is being used to initiate focus. He doesn't state whether he is using AF-S or AF-C... an important distiction! He says his camera is set for "focus and recompose". By itself that is meaningless.
If the camera is set to AF-S then pressing the AF-ON should lock focus (green dot) and then he can recompose (keeping the back button pressed). The shutter should trip immediately upon shutter button press as long as the green focus lock dot is lit.
If the camera is set to AF-C (which too many people in this thread simply assume, although that is how most people use BBF) then focus and recompose will work by focusing and then releasing the AF-ON button and recomposing. But... the release mode needs to be set to Release Priority in this case or the shutter may not trip after recomposing.
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Mike Dawson
Interesting. This isn't quite how my D800 works. I'm sitting with it right now and testing as I write this. In brief, when focusing with AF-On only, Focus priority never works with AF-C.
Details:
Focus is set to a4 AF activation: AF-ON only. In each case, I focus on a near subject using AF-On, then recompose so that an out of focus far-away subject is under the focus point.
There is only one combination of settings which causes the camera not to trigger the shutter: AF-S, Focus priority, stop pressing AF-On before recomposing.
All other possible combinations of focus settings and AF-On activation allow the shutter to fire even though the recomposed subject is completely out of focus:
--AF-S, Focus priority, continue to press AF-On while recomposing on unfocused subject.
--AF-S, Release priority, release AF-On or continue to press AF-On while recomposing on unfocused subject
--AF-C, Focus priority or Release priority, release AF-On or continue to press AF-On while recomposing on unfocused subject.
When the D800 first came out, focus priority didn't work in
any combination when using AF-On. It was a later firmware update that restored focus priority to the one scenario listed above (also known as focus trap). When the camera was first released, there was a lot of frustration in the omission of this functionality. It was a pleasant surprise when it was later restored.
All of the above is only true when shooting with AF-On only. If you change a4 to Shutter/AF-On, then focus priority works with AF-C.
Joe