I am primarily shooting all of my sons Football, mostly at night, and Baseball. I am using a D3s. I have used the Sigma 120-300 and loved the zoom but not real happy with the AF speed at night for football and although I got some really good shots, wide open it always seemed to me to be a bit soft. The Sigma worked OK during the day but I struggled with it at night with the AF. I sold the Sigma and now considering the 300mm 2.8 VR, but I have not used a prime in the past and concerned I will miss having the zoom. Any advice, insight etc,.. would be very much appreciated. Thanks in advance for the help.