As someone who has not shot any video on my DSLRs, can someone explain to me the value in spending 4k on a 50mm zeiss lens to mount on a DSLR that is going to down sample the image to 2 mega pixels?
I shot this quick test four years ago:https://vimeo.com/16611175
It's a CZJ Pancolar 50mm f/1.8, which is not soft at all, and you can see how much sharper video is when you close it down than when it is wide open. And that's on a T2i, soft and crappy by today's standards. Anyone shooting with a BlackMagic, or with a C100, FS700, etc, needs a sharp lens just as much as a photographer does.
For a wider test with lots of different lenses, go here:http://www.similaar.com/foto/lenstests/lenstestsv.html
What's different is the kind of sharpness that we videographers need: we need good acutance, and good resolution is less important. But you'll usually find them both in the same lenses.
So: if the Sigma 50mm Art is as good as the 35mm Art, it will sell very well to videographers.
The only thing keeping me from buying these is that they are electronic lenses: there's no way to control aperture from the lens itself, so it will only work as long as I'm using a camera with a compatible mount. I make a point of buying glass that will be with me for decades, not years (my lens set is vintage Leitz for the Leica-R mount: it works on nearly anything, including Nikon F, Canon EF and M, Sony A and E, Pentax K, m43... so whoever sells the best camera gets my money, I just need to buy a new set of adapters and I'm good to go).