Camerasize just added the Kamlan FS 7.5mm f/3.2 Fisheye to their comparison tool. I compared the Kamlan FS 7.5mm f/3.2 Fisheye to the Laowa 7.5mm f/2 Rectal Linear lens with it above. You can make your own comparison here.
Kamlan FS 7.5mm f/3.2 (Coming soon): Amazon
Regular Edition:
Black 7.5mm lens at B&H Photo
Silver 7.5mm lens at B&H Photo
Lightweight Edition for Drones:
Black 7.5mm lens at B&H Photo
Silver 7.5mm lens at B&H Photo