Nikon mount lens is in stock now -

• http://www.amazon.com/Sigma-210306-18-35mm-Nikon-APS-C/dp/B00DBL09FG/
• http://www.bhphotovideo.com/c/product/967345-REG/sigma_18_35mm_f1_8_dc_hsm.html

You need at least a basic adapter : nikon to mft (they're not expensive) You can add a speedbooster (same mount but more pricey) if you want 2 zoom in one.

I'm torn between getting this with a speed booster or a set of samyang / rokinon primes with a speed booster once I get the GH4 and have focus peaking in camera.

Is it easy enough to get a follow focus on it ? that was my main reason for going with the primes but this is sounding like a better idea in the price range then find something to cover the 50/85mm that would match.

Yep. 50 is coming out but I have the old 50 1.4 and it cuts just fine and is pretty sharp by 1.8. Also some dude in TX makes these awesome pressure, 360 gears for any lens. You can add up to an inch, maybe more in focus through and they are damn cheap. The difference between the Roks and these are night and day. It's really not even close and the damn 16mm Rok doesn't match the rest of the set, so that kills the matching set idea.

Yep. Picked one up for $300. Think Kholi got his for $225 or something like that.

I have the Rokinon 85mm Cine, and although the gearing is nice, optically it's a little underwhelming. It's not bad, but it's nothing special. The construction feels chintzy, and the minimum focus distance seems to be like 4 feet, which is disappointing. I'll probably sell it and pick up a Tokina or Tamron 90mm Macro instead. Not sure how the other Rokinon cine primes compare, but my advice is to avoid them.

I really hope Sigma makes a 85mm f/1.4 for their Art series. That would be very cool.

Good interview, including some details about development of this lens

http://www.imaging-resource.com/news/2014/04/02/sigma-qa-part-i-ceo-kazuto-yamaki-explains-why-so-few-pentax-mount-lenses

http://www.photoreview.com.au/reviews/lenses/aps-c/sigma-18-35mm-f-1.8-dc-hsm-art-lens

Such values are normaly always calculated from the sensor. Otherwise it would be "fun" to compare many different lenses g. ^^

Okidoki

This lens literally stays on whatever camera I am using at the time. The BMCC or the BMPCC with speedbooster. It'll be even better when I add the custom gears from Sean and increase the focus throw!

Very soon Sony A mount and Pentax K mount versions will be shipping.