Is this statement accurate....
From and article from "Learning With Experts" in regards to back button focusing:
"if you forget to release the button when shooting a static object, your camera's autofocus can get seriously confused as it's expecting a moving subject – so again you might end up fluffing the shot."
I thought when using back button focusing that once you hit the button you have designated as the focus you
didn't let go until the shot was completed. ??
No. Not accurate. Expert card is revoked for spreading this false idea. AF does not go searching for a moving subject just because it's focusing on a static subject. Granted, you can release the BFF button once you've focused on a static subject, but never I have encountered a negative result of not releasing the BBF on a static subject.
Similar to IS / VR performance, it's possible the AF function behaves differently on different camera models (old vs new) and / or camera brands. Modern EOS equipment can detect a tripod and the lens doesn't go into a 'loop' searching for motion to counter-act. Your trainer seems to be extending this legacy IS / VR problem onto AF performance.
I can't comment definitively, as I don't know which camera with which auto-focus system, but I have to suspect the original quote is none too accurate. My rationale for thinking this is that the default setting on all new cameras is auto-focus pinned to the half-press of a shutter button. This button is 'not released' prior to the full press, and an even occasional fail of auto focus under these conditions would simply be a fail. My guess is that the prior text was devoted to using BBF to track moving objects and was also devoted to setting and utilizing continuous focus, so there MIGHT be cause to intimate users should turn off continuous focus when shooting static scenes, but that is not expressed here.
will47 wrote:
"if you forget to release the button when shooting a static object, your camera's autofocus can get seriously confused as it's expecting a moving subject – so again you might end up fluffing the shot."
I would suggest it's "expecting" nothing.
What it will be doing whilst you remain depressing the AF-ON button (BBF) is 'reacting' IF there is movement causing it to register not sharp focus which can be caused by your movement or the subjects.
IMO, many people can't handle one "Trigger" reliably, never mind two, or back and forth. Ever since there has been auto focus, the shutter button has worked pretty satisfactorily for me. Muscle memory works under stress.
I have held my BBF button on many static subjects with no ill effects.
Don
Gene51
Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
will47 wrote:
From and article from "Learning With Experts" in regards to back button focusing:
"if you forget to release the button when shooting a static object, your camera's autofocus can get seriously confused as it's expecting a moving subject – so again you might end up fluffing the shot."
I thought when using back button focusing that once you hit the button you have designated as the focus you
didn't let go until the shot was completed. ??
No. Autofocus expects hard edges if PDAF (phase detect AF - or through the viewfinder), or contrast if CDAF (contrast detect AF - as in Live View). Movement and other "predictive" modes are purely enhancements provided to help with moving subjects. But even if you have a moving subject that stops and becomes static, the AF system will not get "confused" - I would suggest that whomever wrote this is seriously confused, however.
Possibly this expert is all fluffed up?
With the exception, lets say a subject is moving and then you continue to pan past the subject, or if your hands are still moving and the focus point is still moving around, the camera will still try to focus. But if the subject is still and your camera is still then you can press the BBF all day long and the camera will not hunt or get confused. Sounds like your on the fence these last few weeks about using BBF. Just DO IT. Change the settings in your camera, go out in the field and try it.... If it ain't for you change the settings back. I'm not trying to bust your chops, but getting out in the field is really what photography is about. Take a chance, have some fun. Find what Works For You... 75% of the advice you get from these forums ais either wrong, or given from somebody that is only Repeating what the have read and have Never actually experienced. Experience in the field will make you a better photographer, Hands Down..
I use BBF for mountain bike racing and never experienced the problem. Complete hogwash.
CHG_CANON wrote:
No. Not accurate. Expert card is revoked for spreading this false idea.
I've been printing my own Expert cards. People are really impressed.
That statement doesn't sound right to me. Is someone going to hold the BB and press the shutter button at the same time? Doesn't that defeat the purpose of BBF? Either way, I don't see the camera getting confused.
Agree it is easier to do one thing than two
Tex-s wrote:
I can't comment definitively, as I don't know which camera with which auto-focus system, but I have to suspect the original quote is none too accurate. My rationale for thinking this is that the default setting on all new cameras is auto-focus pinned to the half-press of a shutter button. This button is 'not released' prior to the full press, and an even occasional fail of auto focus under these conditions would simply be a fail. My guess is that the prior text was devoted to using BBF to track moving objects and was also devoted to setting and utilizing continuous focus, so there MIGHT be cause to intimate users should turn off continuous focus when shooting static scenes, but that is not expressed here.
I can't comment definitively, as I don't know whic... (
show quote)
You apparently don’t really understand BBF. The point is that you leave your camera set for continuous focus and get the best of both worlds. For tracking subjects you continue to hold the button while you shoot for continuous and for static subjects you can release the button once focus is achieved for single shot. That being said, I often keep the button pressed for static subjects and have never had a problem.
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