1d mk3 AF - Object moving away?

[dunganick]

I got a 1dmk3 yesterday, using it at the BTCC Media day, i found the AF performance on objects/cars moving away fast was at best poor. Objects moving towards me it was spot on.

I have had a breeze through the custom functions and cant see anything immediately obvious that might be causing this/solve this, so anyone able to shed some light on this for me?

 

[desantnik]

Hi Nick,

I *think* you'll find thats to do with "C.Fn III-2: AF system sensitivity to sudden subject changes when in AI Servo mode".

Probably the difference is between shooting a car braking into a corner and one accelerating away - ie the latter is a faster change of distance.

What is C.Fn III-2 set to currently?

If its any help, on Nikon's myself and Steve normally have it set to the equivalent of +1 or +2.

Have a look at this for some help on the settings:

http://www.robgalbraith.com/public_files/EOS-1D_Mark_III_C.Fn_III.pdf

 

[NickR]

I got a 1dmk3 yesterday, using it at the BTCC Media day, i found the AF performance on objects/cars moving away fast was at best poor. Objects moving towards me it was spot on.

I have had a breeze through the custom functions and cant see anything immediately obvious that might be causing this/solve this, so anyone able to shed some light on this for me?

Hi Nick,

have you changed Any AF settings from default? I guess you are using single point AF - AI-Servo ? Also I have found really bright Sunlight affects the AF on the MKIII especially shooting into the Sun. Can't see why the AF should work definitely with objects moving away or coming towards you?

Cheers

 

[dunganick]

It is set to 0 currently. So neither fast or slow. Standard was super fast, but this was causing serious seeking indoors. I will try this setting next time out.