How do we say Canon - the camera company name? Is it Keh-nun or Keh-non?
I believe it's pronounced like "cannon". As in a cannon that shoots cannonballs. Here's an example of its usage.
It's usually pronounced the same as the English word "canon", i.e. /ˈkanən/.
Canon is a Japanese company, and their name in Japanese is pronounced kiyanon, but they seem to prefer the English pronunciation in their advertising, even in Japan.