Sony has just announced their new super telephoto zoom lens FE 200-600mm f/5.6-6.3 G OSS lens yesterday. Now Canon users also want their 200-600mm lens, according to latest rumors, Canon is working on their mirrorless version 200-600mm lens: RF 200-600mm f/4.5-5.6 IS USM lens.
Instead of release EF version 200-600mm f/4.5-5.6 IS USM lens, the RF 200-600mm f/4.5-5.6 IS USM lens is most likely to announced. In the past, there have been patent for Canon 200-600mm lens. Though release date for this lens is not available yet, this lens should in the RF lens roadmap.