G'day I just got my self a sigma 150 -500mm lens but I am not sure what way I'll go for filter Brand or type Eg; Cokin, Lee for the quick option Or Hoya ect. Screw on type I am thinking of ND's, Circular Polariser, & maybe some Graduateds at some stage so which type or brand do you recomend. Thanks for your time & effort Dan.