1 of 1 people found the following review helpful
Great small wide prime,
This review is from: Pentax smc DA 21mm f/3.2 AL Limited Lens (Electronics)
I had wanted a small, wide-angle prime for my DSLR for some time, and options are very few indeed. Outside of Pentax and Fuji, even fewer.
I decided on the 21mm as less expensive and a better all-round focal length than the 15mm. 21mm is a good focal length - not so wide as to cause distortion or leave subjects looking very small, but wide enough to capture a whole scene. It may not be wide enough as a travel lens where you want to capture wide scenes in streets with limited space to back up.
The lens is very small, extremely well constructed in metal and a pleasure to use. Image quality is very good - it could be sharper at f/3.2 but is very useable. It can sometime produce yellow_green flare when pointing at the sun. There is some barrel distortion which is visible when taking photos of buildings or other structures with straight lines, but it's easily corrected later (some cameras can do it automatically). However, I'm happy with the IQ it produces, it's certainly better than the 18-55mm kit lens. I wish it were a little faster (f/2.8 or better), but I suppose this would mean it had to be larger.