The Fisheye Optic gives you a very wide view of the world with its 12mm focal length, plus circular distortion unique to fisheye lenses. You can also get really close to your subject as the Fisheye focuses at 1/2″.
The Fisheye does not come with an aperture disk inserted. Without a disk the aperture is f4. This optic comes with 5 aperture disks designed specifically for the Fisheye Optic ranging from f5.6 to f22.
You will need a Composer Series, Muse, Scout, or Control Freak Lens to use The Fisheye Optic.