5d mark iii ai servo odd problem

[Ryant]

This last weekend I was on a boat and I switched to the focus mode that allows all points to be used in ai servo mode. I had my 24-70 2.8 on my 5d mark iii. I had selected the center as my start point for focus and I choose a jet ski speeding by. The camera chose to create a cross of focus points in the center and did not track. If I pointed to the other side of the boat my camera would track the rocks. I choose another slower moving boat and the same thing happened. The camera would not track. I have never had this happen before with the 5d. I switched to zone mode and it tracked fine. I rarely try the all points mode, I am curious what others have experienced. Also I am sure you will ask I tried switching to several of the focus types. I tried the basic generic one at the top, also I tried the mode at the bottom of the tab that says it does focus point switching and tracks distance. I found neither worked. It was sunny out maybe the water and the reflective boats tricked the camera and it couldnt focus?

Ryan

 

[Radiating]

You need to change the behaviors in the autofocus menu, most likely the camera is ignoring fast moving subjects due to the speed of the objects you have selected it to track or some other such problem.

 

[Ryant]

Nope I tried several settings and it would not auto focus even on slow boats in the very sunny side of the boat. I pointed at the other side of the boat that had darker objects to point at and it would focus. I tried several focus menu changes and it did not affect it. It definitely was some sort of error. Also I mentioned that if I was in zone mode it would track fine.

Ryan

 

[awinphoto]

What "case" setting do you have your AF on? There are AF modes such as zone, expanded, single, spot single, etc... and then there's case settings such as erratic, fast moving, etc... that may be to blame.

 

[bdunbar79]

What "case" setting do you have your AF on? There are AF modes such as zone, expanded, single, spot single, etc... and then there's case settings such as erratic, fast moving, etc... that may be to blame.

Yes that autofocus system can get "ugly" if one thing is off. I'd go back through the manual and read everything very carefully again, camera in hand, and make sure every setting is where you want it. There are actually 3 panels that can affect the AF behavior, so be careful.

 

[Ryant]

Yeah ive read the manual severl times and the pdf canon put out. I think I found a bug, it has never locked up like that on me before and it did not lock up anywhere else on the lake with similar subjects.

Ryan

 

[bdunbar79]

Yeah ive read the manual severl times and the pdf canon put out. I think I found a bug, it has never locked up like that on me before and it did not lock up anywhere else on the lake with similar subjects.

Ryan

Noted. I'll keep it in mind when I'm shooting.