Canon Is Testing More Interesting Lenses

Canon has pushed into some new territories with the RF mount, and they are showing no signs of stopping, with some especially interesting lenses now being tested. Canon Rumors is reporting that Canon is testing five new DO supertelephoto lenses: RF 400mm f/3.5 DO IS USM RF 400mm f/4 DO IS USM RF 500mm f/4.5 DO IS USM RF 500mm f/5 DO IS USM RF 800mm f/9.5 DO IS USM Canon has created DO (diffractive optics) lenses before, which use special lens elements that allow for smaller and lighter designs. The most notable example was the EF 400mm f/4 DO IS II USM.