Canon EF 8-15mm ƒ/4 L Fisheye USM
The world’s first lens of its kind, the Canon EF 8-15mm ƒ/4 L Fisheye USM was introduced in 2011 and I acquired my copy in early 2013. It is a versatile lens, producing circular, 180° fisheye images on full-frame cameras. At 15mm, a rectangular image is possible on full-frame cameras. On APS-C, at the 8mm focal-length the top and sides of the image circle are clipped, but a ~175° horizontal image is still possible. The Limit switch locks out the wider focal lengths so no corner clipping occurs on an APS-C sensor (the focal-length is limited from 10mm to 15mm).
This is an absolutely unique lens as far as I know. There is no other auto-focus zoom fish-eye lens with this focal range on the market for any lens mount. In early 2020, the lens is priced at $1249 USD.
The images quality is quite good at the centre of the image, but can be quite soft near the edge of the image circle when shooting wide open. I usually do not bother to de-fisheye any images as that often results in extremely blurry corners.
At the longest focal length of 15mm, on APS-C the lens acts like a very nice ultra-wide angle lens and distortion can be kept to a minimum if you maintain a level horizon. It is possible to acceptably de-fisheye images shot at 15mm and stopped down to ƒ/8 or greater.
It is a fun lens to use, with striking results, but I do wish that I could shoot full circular images on APS-C. While writing this article I went ahead and order the new and well reviewed, fully manual, 210° angle-of-view, Venus Optics Laowa 4mm ƒ/2.8 circular fisher lens, now available in EF-M mount for $199 USD.