1DMk IV focusing with busy bg help needed

i am having difficulty focusing small birds on distance with busy bg. even with "focus search off" the 500+1.4tc works pretty slow at 10m-infinity switch on.. tried different CFNIII-8 but nothing helps.

can anyone tell me what to setup for BIF in 1DMk IV ?

i have 7d also and i find the zone feature good for tracking and it does lock up the in-flight.
1DMk IV focus is just spot on but i really find tracking is bit trouble.

plz guide.

Hi Mital,
Last week I compared both the bodies (1DMkIV & 7D) by renting them for three days - before making a purchase decision !
I also followed Artie Morris's user manual and tried some target based focussing calibration to ensure correct sensor micro-adjustments. This was done with 500/f4.
At the end of this whole excercise -my observation & conclusion has been that the focus lock was much better, faster & definitive in case of 7D whereas I had to struggle a little bit more with MKIV. I faced some remarkable hunting / tracking while using MkIV AF with smaller objects at a far distance - whereas the same were easier to ficus with a 7D. This effect was more pronounced when the light levels of the object and the background were different (say backlit or more contrasty).
(However, the images at higer ISO were certainly better from MkIV as compared to the 7D).

saleel you are right on that part about HIGH ISO. I do have both Arthur morris book on 7d and mkIV and setup with respective changes given in the book but i really found hard on flight with like you have experience of indian birds on distance with busy bg :) 7d locks them for quite a good and long time MK4 instant focus them but release them instantly too while in burst so can say if you shoot in burst with 7d you get 5/6 frames in perfect focus but with mk4 in smaller tiny birds like lapwing on quite distance i find you hardly get 1/2 frames of 5to6 frames bursted.

then i tried stopp on high speed bursting and given a try on single shot bu ALSERVO and surrounding AF assistance and i find it was getting confuse compare to 7d's locked on track.