Sony 10-18mm APSC on FF

I just came across this video[0] of using a Sony 10-18mm APSC lens on a FF camera and the results look nice. The lens looks super compact too. Any thoughts on this instead of a heavier fisheye from Canon with an adapter?

[0] - https://www.youtube.com/watch?v=OVSYLcyg3u8

I would say first that a fisheye and rectilinear lens are a bit apples and oranges.  It may perform OK on land but I haven't seen full res images from the combination so can't comment on the claims it's usable on full frame on land.   The corners that show in the video are dark and without much detail so it's hard to judge how they are performing.

However you are talking about using a 10mm lens on full frame and that will be subject to the same constraints any other rectilinear lens has behind a dome; even if you are talking a 12mm lens that is really quite wide and would need a 230mm dome and shooting at f11-16 to bring the corners into focus on a full frame camera.  The Canon 8-15 will perform quite well in a 140mm dome.  So I would think all your weight savings would disappear with the need to use a big dome.

It may be an APS_C lens but if you use it on full frame, the same dome port optics issues that full frame rectilinear lenses have when placed behind a dome apply.