I have the Sigma 18-35 (ef /af non cine version) and I like it a lot but I would like to get a bit wider. Considering a speedbooster to make it wider and faster. Would also work well with my leica 28 mm which I love but don't really like it closer to 35 as it is with the crop. (obviously, covered by the 18-35 focal range but the leica has it's own look) If I bought a wide lens it would probably be the tokina 11-16. That's around my price range and is close to the same cost as buying a speed booster. What do you suggest- buy the lens, or put a speed booster on the lens i have? Which speed booster is recommended? I've seen the metabones and the canon one for the c70. I'm also open to other wide ideas, and don't mind a prime.