ai servo on 5d mark iii

Hi all. Just a question...

When using AI servo mode i normally set my autofocus points to the 9 center points. Would it be better to use all 61 so that the camera picks the focus points?

May be a dumb question. But my issue with using all 61 will cause the camera to focus on the nearest spot as opposed to me picking just the center foucus...

Hope this makes sense.

First of all, it sounds like you are using some sort of automatic mode for focusing, which isn't a great idea if you want control. You are either in scene intelligent (greenbox) mode, or you are in a manual/semi-manual mode with the '61-point automatic selection AF' selected for your focusing method - which in both cases will cause the camera to automatically focus on the nearest object regardless of what you desire...

So, the smart way to do it is to 1) activate all 61-points OR at least 41 of the cross-type points for better composition freedom (9 points is a pain to compose with) and then 2) change your focusing point selection method...there are 6 options and you need to choose something besides the last one (which tells the camera to automatically choose a focus point). I would recommend playing around with 'Single-point AF' as this would let you choose where YOU want the camera to focus, and you do so by dialing in exactly which focus point youd like to use. Additionally, you can go ahead and expand your focus point using an 'AF point expansion' mode. Should your main target move out of or away from the first af-point you selected, either 4 or 8 surrounding points (depending on the mode you choose) will kick in to keep the autofocus running. Really cool stuff I highly suggest you spend some time in the manual.

http://www.fredmiranda​.com …/topic/1204685/​0#11485916

AI Servo + single center focus

milleniumking wrote in post #16744373
When using AI servo mode i normally set my autofocus points to the 9 center points. Would it be better to use all 61 so that the camera picks the focus points?

No and why?

Are you missing shots?

You buy a 5D3 to get precise focus, not letting your camera to choose and decide where to focus for you. That's what a dumb P&S does with intelligent mode.

In AIServo you have the option to pick an initial focus point and have the camera follow the subject and hand-over to neighboring points. You pick a single point in the AF selection, but the one WITHOUT the little dot inside the square. As you press the button to focus (I use BBF) you will see the AF points that have focus as black sided squares.

MakisM1 wrote in post #16744646
In AIServo you have the option to pick an initial focus point and have the camera follow the subject and hand-over to neighboring points. You pick a single point in the AF selection, but the one WITHOUT the little dot inside the square. As you press the button to focus (I use BBF) you will see the AF points that have focus as black sided squares.

Yeah this is great advice. And to add to that I'd like to say how bad I wished those squares would light up bright green or something...I want the camera to feel like it understands me

There are too many situations and options to know which is best, but certainly I would not let the camera pick the initial focus point.

I would use the smallest focus area that you can still track the subject. Usually for me that is an expanded focus point, very occasionally a group of 9.

IME picking the initial focus point and then allowing the camera to track with all others is somewhat of a specialized feature. For most subjects (BIF, sports etc..) I think you are much better off moving the camera to track the subject (man maybe expanding the focus area somewhat) with whatever focus point you think will provide the framing you want.

If you pick any other than single AF point in AIServo, you will limit the ability to hand-over to neighboring points (note I don't say eliminate, just limit). You can start with any point you want because that will help you keep your composition right. Say you are shooting equestrian. You want to place the AF point towards the top of the photo at the head of the rider. You will still have to follow the horse/rider and you will allow the camera to hand-over left or right.