Welcome to the forum!

As an adjunct to the Tangents blog, the intention with this forum is to answer any questions, and allow a diverse discussion of topics related photography. With that, see it as an open invitation to just climb in and start threads and to respond to any threads.

(Canon) AI Servo or AI Focus for "Animated" Speakers/Presenters

I just shot a 2-day conference, and one of the speakers was really animated and moving around. Having never experienced someone quite like this AND never using any drive mode other than "one shot", I was very unfamiliar with the other two modes. I ended up using AI Focus, because (and I just looked at manual to find out why) in AI Servo, you don't get the focus-confirmation light and the beep. In AI Focus, I could see the light flashing while the beep was beeping, and it was a bit more comforting to know at least the camera was responding. I haven't gotten to those pictures yet.

Any thoughts on what you guys/ladies would do? Which one in your opinion would be better?



  • TrevTrev Moderator

    In the A1 Focus mode, you do need to have the actual focus point you are using on the subject you are shooting just in case you sometimes "auto think" to recompose, a catch for people not used to it.

    Having said that, as long as the subject is not moving back/forward, you should be right in the One Shot focus lock mode, even if he is moving around. Of course some other things do come into play here, like depth of field and the lens you are using.

    If you are on telephoto, and zoomed in a bit and have like f2.8 you are then having to be 'quick on the shutter' to get it sharp.

    In that case what you can do is make sure the camera is set to have shutter fire only when focus lock is achieved, and instead of pressing the shutter halfway, waiting for confirmation, fully depress it as long as the focus point itself is bang on the target, that way the camera only fires once focus lock is achieved. Takes some getting used to trusting the camera, so do practice.

    Also lighting comes into play here, with getting focus lock in low light more difficult and if indoors using on camera flash, you have the Infrared Speedlight's Focus Assist Beam to help.
    [Canon's Flash Assist Beam in my opinion is much better than Nikon's :( ]

    I use 'Continuous Mode' (Nikon) for brides/people walking towards or away and use the focus lock/fire mode 98% of the time.

    I do have a mate who uses a Canon, and he does get great shots of people moving towards him with just focus/lock mode, he refuses to use A1 Servo (said it confuses him, go figure) but he's not waiting for 'confirmation', he just depresses the shutter fully and camera fires when it's on lock and it seems to work.

    I also use Back Button Focus, and Shutter 'only' to fire and I am so used to that I just cannot got back to the other Shutter/Focus/Fire method personally.

  • Hi, Trev -

    Great to hear from you, I was wondering where you've been!

    "In that case what you can do is make sure the camera is set to have shutter fire only when focus lock is achieved ....."  Is this back-button focus?

    Thanks, and I'll start giving things a go.

  • TrevTrev Moderator

    Hi, that question you asked, what I meant there was there is a setting where you can fire the shutter without focus being achieved, silly thing to set but it's there, not related to back button focus.

    In other words if you have Shutter as Focus and Firing as 99% of people do, and for some obscure reason in the settings you can have it set so the Shutter fires regardless of having achieved focus lock or not.

    Try it in a moody setting, pick up the camera, point it at some reasonably dark but don't depress the shutter halfway as normal to lock focus, then just try and fully depress it and it momentarily just won't fire until focus is achieved.

    I have my AF On/Off Button set to lock focus and the Shutter does nothing but only actually fires the camera, that way if I lock focus using that AF On/Off button and hold it, it retains the focus and I can just keep firing as long as I/subject don't move, and as long as I don't zoom the lens in any way.

    Great for groups shots once I have set the ambient/zoom/lights and fire off 3-4 shots instead of having to lock focus via Shutter, recompose, shoot; frame up again, lock focus, recompose shoot.

    Also I find it fantastic for people walking once I set my camera to Continuous (A1 Servo Canon) and as long as I have the focus point on the subject, by holding the AF On/Off Button down I can just fire via Shutter easily and it keeps focussing predictively as they walk.

Sign In or Register to comment.