Spot AF with 1D MK IV

I'm in the process of sorting out the settings on my new 1D MK IV.
The new Spot AF function sounds promising for getting precise focus on small birds.

Have you used the Spot AF setting? Have you found it effective?

Can this setting only be used with telephoto lens with Lens AF stop buttons?

According to Canon's DSLR Camera Guide for this camera that "Spot AF can be activated on supertelephoto L-type lenses by pressing and holding the AF stop button after C.Fn. III-6 AF stop button function has been set to option 7:Spot AF setting.

I have attempted to do this hand holding my 300 2.8 and found that I could not hold the camera steady with my hand on the AF Stop button. For me it looks like it can only used properly with a tripod.

Any comments?

Joe

Compared to the 7D's spot AF implementation, the Mark IV's is clumsy. I have more or less stopped using it.

Thanks Doug. That's what I suspected. Wanted to make there wasn't something I was missing. Too bad, it looks like it could a useful feature. Let's hope Canon issues a firmware upgrade that improves it's functionality similar to the 7D.

Joe

It's true that the Spot-AF have to be avoided while using AI Servo for moving subjects?