Sigma 20mm f1.8 EX DG ASP RF

Hi! I'm new to the forum. I've just bought my first videocamera: Blackmagic Cinema Camera 4k EF.
I'm searching a lens with focal around 11 and 55 in full frame format of course.
I found this Sigma 20mm f1.8 EX DG ASP RF.
So I'm asking if someone know if it is fully compatible with blackmagic cinema camera, in terms of autofocus and aperture.

I also saw the Tokina 16-28 f2.8 PRO FX:

there is fully compatibility with this lens?

Which is better?

thank you, sorry for my english, I'm Italian

Cant speak for the Tokina, but there is no lens I use more on my BMCC than the Sigma 20mm 1.8

Has to be my favorite lens I own. Highly recommend it.

And yes, the auto-focus and aperture controls work as expected.

Some examples from my last short where I used it extensively ( 80%+ of the time )
https://www.behance.net/gallery/2727638 ... terstellar

This clip was shot with several Nikon and "for Nikon" third party lenses on a BM4KV1 URSA which apparently shares the same size sensor as the original BM4K.

The second image in the series of images was with the Sigma 20mm f1.8 DG EX, likely older than the lens you are looking at.

youtube.com/ watch?v=tId-fPKc1zo&feature=youtu.be

I am unable to successfully embed youtube clips here so you will have to reconstruct the web address by removing the spaces between "youtube.com/" and "watch" and add in front the usual "http://www".

I find the lens I have is fine but a bit soft wide-open.

Thanks for the answers, my dubt now is if with last firmware update (which is the last for bmcc??) is possible to have a continuous automatic focus?

No, no and no! None of the BM cameras Supoort or have "continuous" AF (this is more if a consumer and Prosummer function in a camera). BM only has a push to focus on the EF and MFT mount cameras.
DS