Last year I began photographing motorsports. I shot some super bike and GP car races on road courses and shot a lot of motocross and atv races. The gear I used was a 1D Mark IV along with my 70-200 f/2.8L IS II and 300 f/2.8L IS with great results.
I am fortunate to have full access to the motocross and atv tracks and end up strolling all over the track for extended periods of time. After a while, the gear package I mentioned above starts to take it's toll on me due to the weight. I am looking at possibly utilizing the Canon 70-300 f/4-5.6L IS to reduce the weight while retaining the focal length range. I have no concerns regarding the image quality of that lens. I know it's excellent.
What does concern me is that given it's slower speed, will it AF fast enough and accurately enough? I have no concerns on the road races as there is usually a lot of time to lock on and track the vehicles. However, on the motocross and atv tracks, the first glimpse I often have of the bikes and quads is when they suddenly appear over the top of a jump. Immediate and accurate AF is an absolute must in these circumstances. My f/2.8 lenses perform beautifully in that regard, but will the slower 70-300 f/4-5.6L IS be up to the task?
Has anyone out there had any experience they can share using this lens in a similar environment? Your input would be appreciated.
Everything about the lens is a step down, one other thing I'd be careful of, is shutter speed. Can you get the shutter speeds you want at f/5.6 compared with your 300mm f/2.8?
Certainly, the IQ is not nearly up to that 300mm lens, nor the 70-200 either.
This is a case where I'd rent one first before making such a huge downgrade.
From what I can see in the online reviews, the IQ should be more than good enough. It looks like it's not far behind my 70-200 f/2.8L IS II.
Shutter speed should not be a problem. Usually there is a lot of light, shooting outdoors. Besides, I can crank the ISO on the Mark IV pretty high with excellent results.