JeffreyG wrote in post #16352137
To me, 200mm is very limited for soccer owing to reach. Adding the 1.4X TC is better, but then the 100-400 will offer better AF performance.
Then there is the degree of blur and separation possible with each lens.
200mm @ f/4 = 50mm iris.
280mm @ f/5.6 = 50mm iris (obvious, since the TC does not change the iris)
400mm @ f/5.6 = 71mm iris.
200mm @ f/2.8 = 71mm iris.
So if you are shooting with all of these lens options at the maximum focal length possible, the 400mm f/5.6 lens will offer the same blur effect as the 200mm f/2.8 lens.
It's also true that when the action is close and you are shooting at less than the maximum focal length, then an f/2.8 lens will offer more blur than a 400mm lens. But I find on a soccer field that I shoot the 100-400L between 300mm and 400mm most of the time.
Thank you for the info and the education. Since the OP is shooting kids soccer, I find a longer lens less usefull since kids often tend to be crowding the ball and with a longer lens, it is more difficult to get player separation. At closer ranges, there is a better chance of capturing the player and the ball without all the other bodies crowding the shot. Of course this changes with older kids. Again, thanks for the info. For soccer, I try to shoot from angles that have the least distracting background. It helps a lot with shooting without an f2.8 lens.