Most of you have mentioned the difficulty in rotating the zoom ring to take it from 150-600 in one go.
The short video in this field report below, the guy shows it can be push-pull like the Canon dust pump.
Has anyone tried zooming like that? If that works (w/o any damages to zoom mechanism), it would be neat.
I tried it as soon as I got it, after noticing the lens creep when the lens was vertical. I tried it gently though, as I don't know if reversing the intended drive train puts too much strain on something. I'm going to wait to hear if other people break their lens first, before I really get into it.