It used to be that most supertelephoto zoom lenses were significantly below the standards demanded by professionals, leaving you to either buy a stratospherically priced prime or make do. However, in the last few years, we have seen an explosion of better lenses, and one of the most impressive options out there is the Canon RF 100-500mm f/4.5-7.1L IS USM. This excellent video review takes a look at the lens and the sort of image quality and performance you can expect from it in practice.