On the DvxUser website one member had a bad experience renting out his Sony FS7 through ShareGrid : https://goo.gl/9qC4NX
...But it looks like ShareGrid is trying to make things right.
Essentially they are lenses that feature LESS horizontal magnification of your image compared to vertical magnification. This will squeeze a wider horizontal image to fit the size of your sensor, and then in post production your anamorphic image is de-squeezed to make it much wider than the size of your sensor.
Here's a pretty good explanation from RED cameras...http://www.red.com/learn/red-101/anamorphic-lenses
FYI: The Canon C100 mk1 and C100 mk2 cameras capture 12 F-Stops of dynamic range, but you still get banding when recording internal 8-bit files.
Adding noise to footage you've already shot might be enough to fix things, and you might want to look into shooting with an external recorder to up the bit-rate and to record in 4:2:2 color format. ( instead of 4:2:0 )
There are many cine cameras that can use Canon EF lenses with or without an adapter. If you are going to ONLY shoot with Sony cameras and nothing else, then buying Sony might make the most sense.
Otherwise you can use Canon EF lenses with...
- Canon cameras ( 5D Mk3, C100, C300, etc... )
- Panasonic GH4, GH5, Varicam LT, etc...
- Blackmagic cameras ( Ursa Mini Pro is a pretty big deal in it's price range )
- RED cameras
- Sony cameras
Also, you can buy Sigma ART lenses with the Canon EF mount that perform well and cost less than Canon. ( they also have a range of Sigma cine lenses too )
No wide angle lenses ?
i.e 12mm or 14MMS lens
Right now Nikon has more 4K enabled DSLR cameras than Canon does. It really looks like Canon has been sitting on their hands when it comes to 4K video.