Hallo . I love to take pictures of indoor volley contests . I currently had a NIKON D750 . In your opinion what would be the best choice between NIKON 80-400 F4.5-5.6 Vs SIGMA 120-300 F2.8 ex dg os hsm ? I don't care about optical weight because further taking sport pictures I practise a lot of sports ....... I really thank you in advance for your comments and opinions . Have a nice day .