Back Button Focus
Oct 30, 2012 13:16:35 #
I use back button focus lock on my Canon 7D. Does anyone know when you use AI-SERVO, do you hold the back button down during the shooting cycle? Since you don't get a focus lock beep in AI-SERVO, how do I know it's in focus?
Oct 30, 2012 13:26:32 #
Never used it never will, 45 years in photography, half press the shutter release, job done
Oct 30, 2012 14:03:43 #
Once you have locked the focus at the desired distance you can change the composition without changing the focal point. Just make sure you're aperture is set for the depth of your subjects front to back.
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Oct 30, 2012 14:33:19 #
big bear. I understand I can lock focus and recompose. When in AI-SERVO there is no indication of focus lock. SO so I need to hold down the back button focus button so it continues to re-focuses?
Oct 30, 2012 15:01:33 #
Oct 31, 2012 07:03:55 #
So is there any advantage to BBF over using the half shutter release method?
Oct 31, 2012 07:15:26 #
gemlenz wrote:
big bear. I understand I can lock focus and recompose. When in AI-SERVO there is no indication of focus lock. SO so I need to hold down the back button focus button so it continues to re-focuses?
I figure when the lens stops trying to acquire focusing on my subject it's focused and release my back button. I don't wait for the beep.
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Oct 31, 2012 07:23:03 #
JeffT
Loc: Central NY
I also use BBF on my Canons. You are correct; holding the back button continually focuses when in AF-Servo mode.
Oct 31, 2012 07:36:03 #
Oct 31, 2012 08:42:09 #
andrew.haysom
Loc: Melbourne, Australia
redpepper wrote:
So is there any advantage to BBF over using the half shutter release method?
I have used BBF on my Canon 60D for over a year now and would never go back to half-shutter-press. The biggest advantage for me is on second and subsequent shots where you don't want to refocus, you just keep shooting. Using the old way, the second press of the shutter would have caused a refocus by the camera. I shoot a lot of birds and when trying I get focus through foliage etc this is a big help.
Oct 31, 2012 09:18:00 #
GeoffHD
Loc: Essex UK
Surely AI-Servo is for subjects that are moving, Pressing the button half way in this mode does not retain that focus if the subject has moved, it will alter to keep the subject IN focus.
If want to retain that focus and then recompose use 1 SHOT mode.
If want to retain that focus and then recompose use 1 SHOT mode.
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Oct 31, 2012 09:47:54 #
gemlenz wrote:
I use back button focus lock on my Canon 7D. Does anyone know when you use AI-SERVO, do you hold the back button down during the shooting cycle? Since you don't get a focus lock beep in AI-SERVO, how do I know it's in focus?
Watch the view finder. If shooting in continuous you will most likely get your shot.
One of the biggest advantages of BBF is you do not have to worry about the camera trying to refocus when you push the shutter button. You can pick a spot in anticipation, focus and wait for the action. Such as waiting for a bird to fly in a certain direction. Another example, focus on second base and wait for the runner from first. You do not have to wait for the camera to find focus as the runner comes sliding into second, you are already focused. Start shooting, in continuous, and continue thru the action.
Jim D
Oct 31, 2012 09:54:43 #
oldtool2 wrote:
quote=gemlenz I use back button focus lock on my ... (show quote)
Great description for this, Jim! Thanks!
Oct 31, 2012 10:15:23 #
tk wrote:
quote=oldtool2 quote=gemlenz I use back button f... (show quote)
I started using BBF earlier this year back in May after reading about it, and will not go back. I find it works very well for me being a wildlife photographer, especially with BIF. My thanks to birdpix and swamp gator for introducing me to this.
For those of you not familiar with this practice, or trying to learn more about it, read the first couple of pages of this thread.
http://www.uglyhedgehog.com/t-39889-1.html
It also explains the advantage of using the larger button on the back.
I actually find it feels more natural to me because of the way I hold the camera, I find my thumb in that section of the camera normally.
Jim D
Oct 31, 2012 10:38:10 #
bamfordr
Loc: Campbell CA
Just started using BBF a few months ago as a result of advice in a Canon seminar.
The thumb positioning is pretty natural; it is taking me a while to remember to do it. The ability to recompose makes it worthwhile, but I discovered (the hard way) that here are a couple of settings in C.FN III on my 7D that can wreak havoc with autofocus:
#1 "AI Servo Tracking Sensitivity" [I set to between 0 and Fast]
#2 "AI Servo 1st/2nd img Priority" [I set it to zero]
#3 "AI Servo AF Tracking Priority" [I set it to zero]
The thumb positioning is pretty natural; it is taking me a while to remember to do it. The ability to recompose makes it worthwhile, but I discovered (the hard way) that here are a couple of settings in C.FN III on my 7D that can wreak havoc with autofocus:
#1 "AI Servo Tracking Sensitivity" [I set to between 0 and Fast]
#2 "AI Servo 1st/2nd img Priority" [I set it to zero]
#3 "AI Servo AF Tracking Priority" [I set it to zero]
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