Getting very annoyed with my 1D Mark IV

butterfly2937 wrote in post #17834941
Have you tried using the focus points to the left and right of the selected AF point. It would help to see samples and know what custom functions you have set. It is really hard to comment without seeing the photos in the sequence. Reset all the custom functions to default and try setting up the custom functions again.

I set my Custom Functions to this with the exception of leaving safety shift off and changing the Tracking sensitivity based on the subject, Haven't found a sweet spot yet for that.
http://www.sportsshoot​er.com/news/2371

I'll have a look when I get home as I think I do have that activated if it's struggling to lock on.

Those look good. Are you using all focus points or one of the single point plus surround? You do need to make sure your shutter speed is correct. With a busy background and when the subject in small in the frame I prefer the single point plus left and right helper points while I work hard to keep the center focus point on my subject. With a person running toward you and bouncing up and down and arms swinging you have to work hard to keep the focus point on the face and I always use the left and right surround only for that. Turn down sensitivity to the second to the lowest setting. If the person is really small and far away wait ti start tracking until the subject is a little larger in the frame.

Phoenixkh wrote in post #17834843
I read in one of the guides about the two focus points above center and below center. Do you use them at all? I'm not quite sure how to describe it other than to say... if you select the point right above or right below the dead center point... you get double auto focus points. I already have the expanded auto focus points selected in the menu.

Any thoughts, Steve.... or anyone else?

That is because the focus points are staggered, and it is not restricted to the centre point.

butterfly2937 wrote in post #17835053
Those look good. Are you using all focus points or one of the single point plus surround? You do need to make sure your shutter speed is correct. With a busy background and when the subject in small in the frame I prefer the single point plus left and right helper points while I work hard to keep the center focus point on my subject. With a person running toward you and bouncing up and down and arms swinging you have to work hard to keep the focus point on the face and I always use the left and right surround only for that. Turn down sensitivity to the second to the lowest setting. If the person is really small and far away wait ti start tracking until the subject is a little larger in the frame.

Always use Single Point AF with surround points. Not sure what you mean by helper points.

DJHaze596 wrote in post #17835202
Always use Single Point AF with surround points. Not sure what you mean by helper points.

Now I'm home just checked mine and it's custom function III-8 is set to 2 same as yours.

Sensitivety is set to the middle. I've found that to be ok for all my sports tracking cyclists. BIF I don't know, not tried it and could be way off.

DJHaze596 wrote in post #17835202
Always use Single Point AF with surround points. Not sure what you mean by helper points.

Look at pg 222 of the manual. C.FnIII-8 option 1 Left/Right Af point.

Quick Update, Micro Adjusted the 50mm STM to -11 and wow what a difference. Pulled focus and had a lot more keepers. Took back my 70-300L so I cannot do any BIF test till I get my 300mm f4L back on Wednesday. Anyway, everything is starting to look better.