This was shot using the Panasonic GH5.
Also forgot to mention in the video that the the Olympus has a constant F2.8 aperture the Fotasy has an F3.8.
The Fotasy seemed to be much wider even though I had both lenses at 8mm maybe because of the Fisheye?
Anyways hopefully this helps you in your buying decisions.
Amazon Links to both lenses below
Olympus 7-14mm - http://amzn.to/2smovyt
Fotasy 8mm - http://amzn.to/2tpKX9P