I used Canon cameras for many years, and one of my absolute all-time favorite lenses was my Canon 11-24mm ultra-wide zoom. I made the switch to Sony a few years back, and I love using my Sony 12-24mm f/2.8 zoom lens, which I consider to be one of the best wide-angle zooms ever made. When I want to go wider, I reach for my Venus Optics Laowa 9mm Dreamer lens, and between these two lenses, I'm able to adequately scratch my ultra-wide itch. But I've got to say, I am experiencing some severe lens envy at the moment with Canon's announcement of its upcoming 10-20mm f/4 L IS STM lens for its full frame R line of mirrorless cameras.
I don't have my hands on this lens (it won't be released until November), so I can't say whether the 10-20mm will be a dud or a rock star (or something in between). But, I'm guessing that Canon will hit a home run with this one (sorry, when I experience lens envy, I start to haphazardly mix my metaphors). Here's a few specifications that I think will make Canon users very happy.
Incredible 10-20mm coverage on a full frame camera: That's super wide!
F/4 aperture: Some users might prefer an f/2.8 aperture, but that would greatly increase the cost, size, and weight of the lens. Landscape photographers in particular will appreciate the f/4 aperture, as they don't need the wider aperture, and it helps keep the lens more comfortable to carry on hikes.
Minimum focus distance of approx. 9.8 in./0.25m: This allows you to capture extreme near-far perspectives.
Relatively small size and weight: This lens is considerably lighter and smaller than the EF11-24mm lens (which is a bit of a beast).
Of course, because of the ultra-wide angle of view, even at f/4 Canon had to make this a "popeye" design, which means the glass curves outward considerably, making front filter use challenging. The lens does have a rear slot for filters, but the rear slots aren't as easy to use as front filters.
Who is this lens for? Photographers who enjoy grand landscape compositions will love this lens, and it will be great for "expanding" interiors, so architectural photographers might salivate over the 10-20mm focal length as well. Ultra-wide lenses excel at extreme, near-far compositions, because they allow the photographer to radically distort the relative scale of objects in the scene; the wide angle of view makes everything look smaller, but getting close to an object can make it appear much larger. So, no matter what type of photography you do, an ultra-wide like the 10-20mm lens will open up new, creative interpretations of your subjects.
Canon expects to start shipping the lens on November 2 (don't be surprised if it takes longer than that for the lens to be consistently in stock) with a price of $2,299.00. Since I'm no longer shooting Canon, I won't be using this lens myself, but I've got a feeling that this lens will become the new gold standard for ultra-wide zooms!
Wide-Angle Photography Class
Wide-angle lenses are the hardest to learn how to use. I've got an upcoming webinar class on Wide-Angle Photography, where I will teach how to use your wide-angle lens to create compelling and unique landscape, wildlife, and travel photos. You'll learn both the technical and artistic considerations unique to wide-angle photography, including composition, dealing with the distortion inherent to wide-angle lens designs, and the importance of carefully selecting your position. The webinar is free for PRO Members. Learn more.