Currently, Canon is working on a new super telephoto lens that is slower than f/4, according to the latest Canon rumors.
The source this new super telephoto lens will be announced some time in 2016 with affordable price, but it doesn’t talk about the exact focal length, speed of the lens or even if it will be a L lens.
And you know, Sigma and Tamron have their super telephoto zoom lenses with affordable price: Sigma 150-600mm f/5-6.3 and Tamron 150-600mm f/5-6.3. So, Canon need to get rid of this missing in this sort of lens.
Stay tuned for more info.
Read more: Canon Rumors.