It is said that the first of these will be the Canon RF 300mm f/2.8L, though there is no firm feeling on the second. While these long pro lenses will certainly be of interest to Canon EOS R5 and Canon EOS R6 shooters, their primary purpose will be to equip with the Canon EOS R1 – the anticipated successor to the Canon EOS-1D X Mark III flagship DSLR.
Rumors of a Canon RF 300mm f/2.8L first emerged last June, with Canon Rumors noting that it "will come with a 'new and unique' feature for super telephoto lenses", though no suggestion was given as to what this could be.
The same report noted that Canon had no plans to update the EF-mount versions of the 300mm f/2.8L and 500mm f/4L, which many interpreted as Canon scrapping its DSLR designs for those lenses and upcycling them into RF-mount models instead.
As such, it is possible that the second lens could be an RF 500mm f/4L or even f/2.8L. Others have pointed out that, historically, Canon has launched 300mm and 400mm lenses almost in tandem, so if that tradition continues then an RF 400mm could well be on the way.
Of course, all these proposed focal ranges are covered by the new Canon RF 100-500mm f/4.5-7.1L IS USM, and both the Canon RF 600mm f/11 and Canon RF 800mm f/11 provide more extreme super-tele coverage – though none of these are suitable for professional sports photography, which is what this pair of new lenses is targeting.
Indeed, Canon Rumors reported that they would both be launched alongside the EOS R1 in time for the 2021 Olympic Games – though the camera itself, and perhaps the lenses too, will likely be unavailable to the public until the end of 2021.
One thing is for sure: after a dynamite 2020 for its RF system, Canon clearly has no signs of slowing down in 2021!