The main contender is the Sony FE70-200 F2.8 GM. The Tamron is much lighter, smaller to carry in a bag , can focus closer and is half the price of the Sony FE70-200 F2.8 GM; The Sony FE70-200 F2.8 GM keeps its contant length when focusing, optical stabilisation and additional buttons (focus hold, distance limitation, AF/MF, OSS) and is compatible with Sony TC1.4 and TC2.0.