FSATIN Loc: Westchester, NY

I have read many posts about BBF and so I decided to give it a try. I have a Canon 70D. When I use the BBF in one shot focus mode the green confirmation light comes on when it achieves focus. If I use AI Servo (which many articles say is best with the BBF) the light does not come on. I wrote Canon customer service and they told me that the light should come on in AI servo as well. Did I do something wrong with my setup? Any ideas would be greatly appreciated. Thanks in advance.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

I can't comment on the 70D, but I have my T3i set for BBF and also for AI servo. I have just done a test with three lenses.

With a Canon EF 70-300mm IS zoom and EF-S 10-22mm zoom I get the confirmation light when each of the lenses first achieves focus. If I continue to hold the back focus button and aim at something else the auto focus tracks and refocuses but does not give any additional confirmation. There is no audible beep when focus is achieved.

With a FL 55mm f/1.2 manual focus lens adapted to EF mount and with a focus confirmation chip I get both a confirmation light and audible beep when focus is achieved. With above two zoom lenses in manual focus mode then the behavior is the same as the 55mm f/1.2 manual focus lens.

It also depends how you have assigned the shutter / AE lock functionality under custom functions. In the AF mode section the manual describes how each of the AF modes operate and what feedback (lights, beeps etc.) is associated with each setting.

I would recommend that you refer to your manual and try each of the various settings to see what happens.

Good luck.

FSATIN Loc: Westchester, NY

Thanks for the info. I have the same two canon lenses as you, but when I used AI servo I did not get the green light. I do get it with one shot focus. Is it possible that I have to program something different for the AI servo method?

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

It is certainly possible, which why I suggested experimenting. I can only check what happens with a T3i or T2i and the 70D is probably similar but not necessarily exactly the same. It also will probably vary according to how you have set up the custom function options for AE/AF lock. I don't know the answer for a 70D but your manual may have the answers....

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

Just guessing, but you may have inadvirtintly (spelling?) programed something you did not want to. Why not revert to Out of the box settings and start with a clean slate. It may help

marki3rd Loc: Columbus, Indiana

I checked and my Canon 550d/T2i works exactly the way you describe your camera working. If I set either "One Shot" or "AI Focus" modes I get the green focus confirmation light in the view finder. But when I set "AI Focus" I do not get the green light even though the camera does auto focus fine.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

I think this may have something to do with how focus points are set but I am not sure. When people talk about green focus confirmation lights I firstly get confused and then think that my camera may be different. However, I look at the focus point indicators in the viewfinder which are red and I don't pay attention to the data and the bottom of the view finder for focus - which I think is green, just for the other details about shutter speed, aperture, exposure, ISO and so on.

On my T3i, I have focus point set to the center point only, and I get a red focus point flash using BBF but not a green light at the bottom of the viewfinder. This may be something to do with my camera, or it may be something to do with how the feedback signals change in different modes.

My suspicion is that the OP's camera is working OK, but the feedback changes depending upon the settings.

The suggestion of doing a reset may be a good one, especially followed by a detailed exploration of following the manual for different modes and checking whether the camera does what the manual says it should do.

Also, do consider the red focus point indicators as well as the info at the bottom of the viewfinder.

Good luck

davidrb Loc: Half way there on the 45th Parallel

Your camera is working properly, the green light will only illuminate in one shot mode. On page 101 of the manual ( I think that is close) it states that in Ai Servo AF to light will not illuminate nor will the beep chirp. That is fairly common with Canons, at least mine all function that way. I think that the selected focus points will illuminate in the viewfinder when focus is achieved while in Ai Servo AF.

mwsilvers Loc: Central New Jersey

The focus light should only come on in One Shot and in AI Focus as long as your subject is not moving. When your subject is moving, AI Focus and AI Servo work similarly. That is the focus is not locked and automatically changes as the position of your subject changes. That is why the focus light does not come on in AI Servo. It is perfectly normal for all EOS cameras.

Grnway Loc: Manchester, NH

Agreed. I have a few Canon bodies and had the same experience. The green light will not go on in servo mode because it is a constant state of focus. The focus does not lock, therefore no green light.

foathog Loc: Greensboro, NC

inadvertent |ˌinədˈvərtnt|
adjective
not resulting from or achieved through deliberate planning: an inadvertent administrative error occurred that resulted in an overpayment.

foathog Loc: Greensboro, NC

canon - What is the difference between AI Focus and AI ...



AI focus is constantly active for moving subjects. Therefore it doesn't have a SET focus so the green light does NOT come on. Single shot is just that. One set focus.

sidney Loc: London.Eng.

THanks for all that info..was having the same situation.

mwsilvers Loc: Central New Jersey

That's incorrect. What you are describing is AI Servo. AI Focus is a combination of One Shot and AI Servo. With AI Focus the focus light will come on if you focus on a static subject, like One Shot. If the subject moves AI Focus will behave like AI Servo and automatically change focus. The focus light will not turn on. Generally most people don't use AI Focus. As a hybrid system it is not as effective as either One Shot or AI Servo.

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

I know the meaning and even used it properly. I can explain the function of dual chamber pacemakers as well as implantable pace ICDs but i can't spell a dam thing.(pun intended). I never paid attention to grade school gramer.(another intended pun)