Canon developing a new “L”-grade telephoto lens (200-600mm)?

We got word Canon is working on a new “L”-grade telephoto lens. The new telephoto lens may be something in the 200-600mm range, with apertures not wider than f/4 nd likely not constant over the zoom range.

Canon has many powerful telephoto lenses in the “L” range of their offering, such as the amazing EF 70-300mm f/4-5.6L IS, my favorite travel zoom, or the more far reaching and also heavier EF 100-400mm f/4.5-5.6 IS II, a favorite among wildlife photographer who can not afford or do not want to carry aroud the much heavier telephoto primes from Canon.

An EF 200-600mm lens would be handy for Canon. Sigma and Tamron are already offering lenses in this segment, for instance the popular Sigma 150-600mm F5-6.3 DG OS HSM Sports or the Tamron SP 150-600mm f/5-6.3 Di VC USD, both more affordable than comprable Canon offerings.