So what does this look like on a APS-H camera?
At 8mm on 1D Mark IV, you get a cropped-off circlular fisheye, which doesn't really look pleasing.
At 12mm on 1D Mark IV, this is the perfect fisheye for a APS-H camera where you maximise the full diagonals.
At 15mm on 1D Mark IV, its more zoomed-in and totally not very pleasing.
Nevertheless, it still makes pretty decent pictures if you know where to point this lens at. Most APS-H users would find that they only end up using 12mm, which produces fisheye images like these:
Canon 1D Mark IV, 1/8th, f/4, ISO 3200, pure unedited JPG image.
Canon 1D Mark IV, 1/40th, f/4, ISO 1600, pure unedited JPG image.
One downside is the lens cap (LENS CAP 8-15) is plastic, and I doubt you might be able to get a replacement if this is damaged. When I go around shooting with this lens, I usually keep the lens cap with EW-77 hood on until I am ready to shoot something as I do not want to end up knocking or leaving fingerprints on the front element.
Cheers hope this was useful for you!