Summary: It won't fit the non-IS 75-300mm lens or the newer 70-300mm IS lens. Newegg has it for about half the price of online photo stores in Canada.
Pros: This lens hood is made for the EF 75-300 4.0-5.6 IS USM lens. It fits around the outside of the filter, so it doesn't affect the setting of your polarizing filter. It's a bayonet mount, not threaded, so it's a quarter turn to get it on or off.
Cons: It's huge and deep and you have to take it off to fiddle with the polarizing filter.
Summary: I'm sure this lens hood has to fit a 58mm canon lens but which one is beyond me. I spent a half hour on canons site looking for a match with no luck.
Pros: Typical Canon
Cons: I purchased this lens hood for my canon EF 70-300mm F/4-5.6 is usm telephoto. This lens hood will not fit this lens. I have 5 other canon 58mm L glass lenses and this hood will not fit any that i own.
Summary: bought this 58mm lens hood for a 58mm Canon EF 75-300mm 4-5.6 III lens, but the grooves cut in the lens don't match those in the hood. If you have a lens and are looking for a hood, don't go based on the size of the lens, the hoods are designed with specific lenses in mind.
Pros: does its job perfectly, but you have to constantly hold it in place