Hi, Interested in picking up a super telephoto lens. I know that this lens is expensive... and large/heavy. I'm prepared to accept that once optical quality is very good. I've used a Canon 100-400LII previously and was very happy with that, sometimes wishing for longer reach. Conversely I've also shot Pan100-300 on m43 (600mm equiv reach) and often wished it performed better at the long end. Has anybody here tried the Tamron 150-600 or 70-400 with LAEA4 on A7 system? Care to comment? Thanks, Tom.