Yo lioneldude, same lionel from the f1sg forum?
But yeah. The problem is... fast lens, AI servo, as lionel carefully mentioned is "useful" but not mandatory.
Why? Cos even at f11/f22, you can blur the background since panning deliberately does that, although not in the bokeh way that so many are familiar with.
AI Servo? Great if you are using AF and tracking for panning. Useless if you are using MF.
So yes, useful if you are starting out but not a must.
So TS, confused already?
Yeah i'm the same guy on f1gpsg forum.
When you are composing your shot, the aperture is wide open and hence it helps with your AF. Your shot setting may be f/11 but during focusing it is open at f/2.8 or the largest aperture you have.
AI servo only good if you should from certain areas that you can track the car comfortably without hitting the fence, i.e from higher ground. I found this useful when i shot from row 15 of Turn 2 which is above the fence and able to track the car as it goes thru turns 1 and 2.
However, if you are just trackside, AI servo can work with IS mode 2, by delibrately swinging your lens to blur out the fence in your view finder and such that the AF cant find the fence. Of course there are times when you hit a fence post or fixture, so you prob got to experiment and see what works.