Samyang fisheye for street photography: original
Samyang (Rokinon/Bower/Opteka/Vivitar/Walimex etc.) 8mm lens is unique - the only fisheye which has a stereographic projection. This projection produces the most pleasing and undistorted shapes - even at the very edge of the frame, despite the fact that it manages to pack 167 degrees diagonally into a shot (on Canon; on Nikon, it is the full 180 degrees). Huge field of view plus minimum distortion makes it an interesting lens for candid street photography - the kind where you are right in the middle of the action.
Here is my first test of the lens for street photography. I was walking holding my camera at the waist level pointing straight ahead, and was making occasional shots, looking mostly down at my camera (so no one was aware I was shooting them). I set this manual lens to f/8 and 1.5m - this should make everything sharp between 1.3 m to infinity. Camera was set to ISO 200 and aperture priority (the exposure here was 1/400s). The shot was cropped.
As you can see, if there is enough of light, this lens is quite useable for street photography. Due to its stereographic projection, faces do not look distorted. For comparison, check the de-fished version of this shot below (you'd get such a shot with a rectilinear UWA lens with focal length 8mm - like Sigma 8-16 mm lens). On the de-fished shot, faces closer to the frame edge are rather distorted.