Looks like Canon is preparing one of its most versatile professional telephoto lenses yet. A newly published patent suggests Canon is developing an RF 300mm f/2.8 L IS USM with a built-in 1.4x teleconverter, allowing photographers to switch instantly between 300mm f/2.8 and around 400mm f/4 – giving them two lenses in one body.
If this sounds familiar, it's because Nikon already did it first, with its Z-mount super-telephoto primes: the Z 400mm f/2.8 TC VR S (extending to 560mm f/4) and Z 600mm f/4 TC VR S (extending to 840mm f/5.6). Canon's approach could be even more compact – and aimed at a broader range of sports and wildlife photographers.
