Canon EF 24-70mm f/4L IS USM Lens. When the Canon EF 24-70mm f/4L IS USM was announced about 9 months after the 24-70L II, quite frankly, we were left a bit bewildered. Why would Canon release a lens with a shorter focal length range than the popular EF 24-105mm f/4L IS USM and charge significantly more for it? EF 24-70mm f/2.8L USM: EF 24-70mm f/2.8L II USM: EF 24-70mm f/4L IS USM: EF 24-85mm f/3.5-4.5 USM: EF 24-105mm f/4L IS USM: EF 28-70mm f/2.8L USM: EF 28-105mm f/3 Arj5f.