Here is a round-up of hands-on reviews and previews of the brand new Canon RF…
Canon RF 15-35mm f/2.8L IS review by Photography Blog.
The Canon RF 15-35mm f/2.8L IS is one of the “holy trinity” lenses for the EOS R system. A lens that’s not for everyone’s budget.
From the conclusion of the Canon RF 15-35mm f/2.8L IS review:
This lens is lovely and sharp, while also being very good at keeping distortion to a minimum. W’ve been using it with a Canon EOS RP, which arguably is not the best camera to use it with. But even the 30 megapixel Canon EOS R probably wouldn’t even do it justice – perhaps Canon will be announcing something with an ultra-high resolution sensor targeted more squarely at professional users than the existing line-up some time soon.[…] Image quality from this lens is fantastic and if you’re somebody who has a need for an ultra-wide-angle lens for the Canon full-frame mirrorless system, it’s hard to deny just how excellent it is. Read the review at Photography Blog