Before I purchased a Full Frame camera body, EOS 6D, I wanted a wide lens to photograph landscapes and cityscapes with a Rebel T5. I chose the EF-S 10-22mm f/3.5-4.5 USM lens because it had a wider zoom range, and the front element did not rotate when the lens focused, which can be crucial for using CPL filters
I shot the above photo, and then turned around and shot the two men fishing below..
The fact that the 10-22mm lens lacks IS doesn't mean much. Not unless you're inches away from your subject, the angle of view is so wide that you're not going to notice slight camera motion blur until you start pixel peeping. Besides, the 10-22mm was also slightly faster than the 10-18mm.
I bought the Full Frame camera, and I was back to square one. I lacked an ultra wide angle lens. I took a chance and purchased a Rokinon 14mm T/3.1 cinema lens. Rokinon also makes a version for stills, 14mm f/2.8. The lens works well on a full frame body, especially for capturing wide field pictures of the night sky.
Some people complain that the lens is soft at the edges, in the corners, and that it vignettes more than they like. I haven't found any of the images to be too soft, and like any ultra wide angle lens you will get some vignetting. However, all of these issues are virtually non-existent on an APS-C body camera.
The above photo was shot with a 7D Mark II and the Rokinon 14mm T3.1. I beleive the equivalent f/stop was about f/8. The dark area in the center of the shot is how the scene appeared at the time. It is not an artifact from the lens. There was a severe weather front passing overhead. The shot has been cropped to 16:9.
I love using the lens to capture shots of storm clouded skies, particularly with an APS-C body. However, the above photo was a 2 second exposure taken with the 6D in near pitch darkness at first light of day as the sun lit the upper atmosphere, which provided the clouds with a backlighting. I only used the 6D for its' low light capabilities. As it turned out, I probably didn't need low light perfromace with a long exposure, but the clouds were literally racing cross the skes, and I wanted to keep the exposure as short as possible, to freeze the cloud motion.
