You already received some good advice. Let me add some comments:
- Do you need AF ?
- Do you need WR ?
An alternative lens could be the Voigtlander Nokton 58mm f1.8. The lens is MF. The IQ is superb as well as the bokeh. The lens is built as a tank. The price is about US$380 new.
I use this lens for outdoor shooting in low lights on my K-7. The lens has been in the mud, in tropical rainstorms, salty sprays, and other atrocious conditions. Although it is not badged 'WR', that lens is really weather resistant.
It may be a nice alternative equivalent to a MF-WR lens.
Hope that the comment will help...