The Canon RF 70-200mm F2.8L IS USM lens is the first RF lens to feature dual Nano USMs. As Mike explains, these are integral to the lens's outstanding suppression of focus breathing. "The optical design features a floating lens group that can be controlled independently. You normally have four to five elements in a focusing group, and they move together, but in this case, the floating group can do other things. That's why we have two Nano USMs for this lens, so you can control two different lens groups working independently.
"Another benefit of being able to move the floating focus group is that you can increase the focusing distance internally, so it focuses much closer than the EF version – right down to 70cm.
"The EF version of the RF 70-200mm F2.8L IS USM was such a popular lens for video; it has a versatile zoom range, it's built like a tank and the f/2.8 aperture is ideal for some level of control over the background," Mike says. "But now you've got the 1/8 stop aperture adjustment, even faster focusing and the floating system inside to compensate for the focus breathing."