It was the Sigma 120-400 i had,it wasnt a bad lens for the money but the Tamron 150-600 is better,only used the Nikon 70-300vr a couple of times and that was on my V2 but it seamed ok,you might also consider the sigma 150-500,i dont feel 300mm is long enough for birding,ime considering getting the 300mm pf but i would use a 1,4 converter making it 420mm a lot of the time.