My 8 year old is in Tennis and Skating. (indoors for both)
I have a crop body and 55-250 but its rather slow for indoor use.
I don't want to spend a fortune until she makes it to the big leagues 
In the meantime what do you suggest to get good shots?
I was looking at:
- Sigma 70-200 f2.8
- Canon 85 f1.8
- Canon 100 f2
Obviously a zoom would be the best flexibility but its expensive and I am a little worried that f2.8 is not enough in the indoor skating ring and indoor tennis.
On the other hand I am not sure a prime with 85 or 100 is either too short or too long?
Are there better options?
Any recommendations from people that have shot in these types of conditions?

