If there are things in this world that make me scratch my head, it’s Canon’s RF lenses that aren’t in their L series. With that said, the Canon RF 100-400mm f5.6-8 IS USM is an okay lens that could’ve been more. Granted, it’s also only $649. And for that price point, it’s offering a whole lot to photographers. But at the same time, you’re probably going to find it both frustrating and liberating. However, if you’ve used the Canon RF 100-500mm L lens, you won’t want to go back.