[JJ_SO]

At this point the best solution looks like the Sigma + their adapter. Since they offer two 150-600mm I'd just like to understand whether the Sport version is worth while the extra cost and weight. 

 

It's difficult to answer, I never compared the contemporary to the sports version. The lens hood alone is 290 grams an it appears as it can take some serious bumps It's more than stable enough to rest the lens and camera on it when pointing it downwards. Like the whole lens more or less cries "put water and dust on me, use me in sand and rain".

 

I just put it out of the box again and pointed it at some things closeby. I think I keep it - actually there are some Sports on sale, maybe from guys like me who just gave up too early on learning how to use it. Also, I got two requests of even lower price and I must say, I'm done with people only looking on the price. 1800.- CHF for lens, 1.4× converter, tripod foot and Benro Gimbal is 800 less than I paid for it. If that's not cheap enough, I'm not willing to sell an adjusted lens for less.

 

Another thing you might consider, if landscape is primary: ø 105 mm for the filter thread vs. ø 95 mm can save you some bucks for polarizers.

 

I'm not sure if I would go for Sports again. If you don't have regular sandstorms or monsoon rain in Italy, I'd save 1 kg if I were you. Also, you can remove the tripod foot on the contemporary version, which makes the whole thing even lighter. I can't, instead I got a very long foot to balance it on the gimbal head - and when zooming you need to balance again. Except sealing and tube for rough environments, the Sports version has not much to offer as a difference. Sigma itself doesn't state it very clearly.