In need of advice

Alex great photos, and as Marko says says another great thread.

Thank you so much everybody for your help. Although the flash is not an option this time first, because I still don't know how to sync, (I will have to learn about it first) and second because I am usually very close to the dancers. I'll try to get a better lens soon based on recommendations.

Alex, by the way you have an amazing work! I Loved the motion!