I shoot high school sports, and an advisor to the student sports photographers.
Warning, because of the LOW light level at many public high school venues, shooting high school sports is about equipment.
Parents and teachers often don't want to hear that, cuz that means $$$$.
Here are two video that I did for my class which may help you
In the gym.
For night field games under lights. Though this is aimed at stadium games (football, soccer, lacrosse)
Bottom line for LOW light, is the old saying
"in LOW light, FAST glass wins."
In very low light, sacrifice the flexibility of a zoom for the speed of a prime.
The lesson channel is
I have video lessons for basketball and baseball.
Basketball:
When I shot basketball in the high school gym with my D7200, I used a 35/1.8, instead of a f/2.8 zoom. The f/1.8 prime let me shoot at ISO 3200, instead of ISO 6400.
I shoot on the gym floor. If you are in the bleachers, you may/will need a longer lens, 50/1.8 or longer.
If you are farther away, you may need the 70-200/2.8.
Baseball:
What position does he play? And are you fixed in position, or can you walk around the outside of the field? These two questions will determine the focal length of the lens.
You have two very different conditions, day and night.
During the day, with plenty of sunlight, ANY lens will work. My general suggestion are:
- one lens = Tamron 18-400
- two lens = 18-140 + 100-400
If you have LONG shots (like to or from outfield), then you want the 100-400 or 150-600.
If you are only shooting infield, then the 18-140 will be adequate.
Focal length depends on distance from you to your son.
At night, you are significantly limited, presuming the usual high school level field lighting.
- 70-200/2.8
The lack of LIGHT drive the lens, not the distance.
Gud Luk