A 70-200mm f/2.8 lens is one of the most versatile and popular options out there, but not everyone needs that f/2.8 aperture or wants to spend that kind of money. A 70-200mm f/4 lens offers the same versatility in a smaller and more affordable package, making it a great alternative for a lot of different photographers and filmmakers. This great video review takes a look at Canon's mirrorless option, the RF 70-200mm f/4L IS USM lens.