First of all, let’s define an ultra-wide-angle lens: anything wider than 24mm on a full frame camera is considered traditionally to be an ultra-wide lens…
These are a few of the more common lenses available for full frame sensors:
Canon 11-24mm, Sigma 12-24mm and Nikon 12-24mm
For APS-C sensors, there is a Sigma 8-15mm available; it gives you approximately 12-24mm on a Canon body.
Unlike a fisheye lens, these are rectilinear lenses which control barrel distortion pretty well.
In my opinion, these lenses, which can give an area of view (AOV) from about 110 degrees to 126 degrees ( in the new Canon), are a specialty lens to be used in the right circumstances…it would be a big mistake to think of using them in every landscape image. These lenses are all about perspective, near-far relationships; as in all landscape, it is important to have a foreground, midground and background. It won’t be necessary in all your landscape images, but with an ultra-wide, it is critical. These lenses diminish everything in the distance and enlarge foreground objects: this can work to your advantage or disadvantage. A few masters of this lens are: Ian Plant, Marc Adamus, Max Rive and Ryan Dyar…look at their images and notice how the foreground relates to the background. Here are some examples of the ultra-wide used successfully and others not…










The thing that I love about a wide angle lens is that it allows the photographer to get very close to the foreground subject. With its extreme depth of field you can be a foot away from the foreground and have a sharp image all the way to infinity.