Ernie +1 !
A good lens choice in a great location will produce better images than the perfect lens in a mediocre location. With basketball both your position with respect to the court AND the angle/height you are shooting from are critical for different shots. If you aren't comfortable holding the camera body in portrait orientation, spend some time developing that comfort because you are going to be using that for the majority of your basketball shots.
Space is tight in most gyms so talk to the relevant AD or official to make sure where you are allowed and then scope out that area to find the best spots. Although it doesn't happen as often as in football, plays in basketball will bleed over the lines so you have to be prepared to retreat/avoid and have an open spot to go and that is especially true if you are right behind the net.
I shot my first indoor soccer game of the new season last night and I had forgotten what a pain it is to work in a confined area where you have very little depth between the field of play boundary and the wall; it makes it more difficult to follow the action so like basketball much of the time you either have to choose a primary location based upon the type of play and players you want to capture or choose the best compromise position for the majority of plays.
For basketball I use a 70-200 F2.8 on one body and a 24-70 F2.8 on the other (both full frame bodies). For indoor soccer the 300 F2.8 works well with the 70-200 2.8 on the second body but in a poorly lit soccer venue (F2.8, 1/640, ISO 12,800) the focus acquisition speed between the prime and 70-200 is obvious although the 70-200 is a pretty fast focusing lens. I will experiment with the 135 F2 later in the season to see how it does as the second body lens.
Depending upon which Canon body you are using, make sure you have the servo AF setup optimized for the type of action. The Canon guides explaining this are excellent so read them with your camera at hand to set it up as you read.
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
