The Canon RF lens lineup is growing nicely, though there is still a hole at the ultra-wide angle end of the lineup. Thankfully, however, that will likely change soon, with a premium ultra-wide angle lens on the way.
Canon Rumors is reporting that Canon is planning to release an ultra-wide lens in the first half of this year. Though there is the RF 15-35mm f/2.8 L IS USM, lenses with significantly wider focal lengths have increased in popularity in the last few years, and I suspect Canon wants to follow up on the EF 11-24mm f/4L with an RF version of some sort. I was a big fan of the original EF 11-24mm f/4L in my review, and I suspect a new version would be popular, particularly with landscape and architectural photographers. Recently, three patents emerged for just such a lens: an RF 10-24mm f/4, RF 9-18mm f/4, and an RF 11-24mm f/4. If I had to guess, I would suspect the 10-24mm f/4 is the most likely to come to market. Canon has shown they like to extend the capabilities of RF lenses a bit beyond their EF counterparts, and this specific design has been rumored for several years. Hopefully, we will hear more news soon!