Here’s where things get really wild. I own a 15-year-old Sigma 15mm fisheye lens (available in many formats) and for this article I borrowed a Canon 8-15mm f/4L lens from Canon UK. What on earth ...

in the form of a fun but flawed 15mm f/8 version. However, the later Olympus 9mm f/8 Fisheye Body Cap lens has developed a cult following – including, apparently, among Canon engineers.