Which is in itself too large and heavy to handhold for an extended period... I tried using a Sigma 70-210 f/2.8 that I bought second hand... I had a hand ache, plus a shoulder ache and a cramped palm after like 1 hour holding it to shoot some performances... oh the 70-400 is 1.5kg heavy... the A900 is 850g... that makes for 2.3kg and if you put on a flash that weighs another 500g, that makes almost 3 kg... think of carrying around a desktop replacement laptop which comes with a 17" screen... not funny...