this is often the “standard” lens for street photographers
it is very useful for wedding photographers, particularly full frame cameras used with lenses of apertures of f/1.4 to give some blurring of the background, and this is an important reason for some to choose a full frame camera over a cropped sensor camera
the new Sigma 35mm f/1.4DG HSM lens (~$US900) is perhaps the best lens in this class although it is not weathersealed and bokeh is not as nice as it could be
Canon EF 35mm f/1.4L ~$US1479
Canon EF 35mm f/2.0 ~$US289
Canon EF 35mm f/2.0 IS USM ~$US849
Canon EF 40mm f/2.8 STM “optimised” for contrast detect AF
Nikon AF-S Nikkor 35mm f/1.4G ~$US1650
Nikon AF Nikkor 35mm f/2D ~$US360
cropped sensor dSLR lenses for Nikon/Sony DX dSLRs
a Nikon/Sony DX dSLR with crop factor of 1.5 requires a 24mm focal length lens to give this angle of view
cropped sensor dSLR lenses for Canon APS-C dSLRs
a Canon APS-C dSLR with crop factor of 1.6 requires a 22mm focal length lens to give this angle of view, although a 24mm lens will give you 38mm equivalence
Micro Four Thirds cameras
these have a 2x crop factor so require a focal length in the range of 17-20mm