Summary: I am trying to find equivalent lenses for switching from my mid-range Canon EOS-D environment to Sony NEX. I am a happy user of the SEL-P1650 and SEL-55210. All these lenses (the SEL-50F18 being the third) are good optical quality for my taste.
Summary: I bought this lens primarily for portrait photography and some video work. It is mounted to a Sony a99 and has been used on my old a700 as well. Starting with build quality: The plastics used are of a good quality and matted to the metal alpha mount.
Summary: It may seem a bit expensive compared with Canon and Nikon 50mm primes, but the quality is great, and at F1.4 it is actually a very useful low-light/available-light standard lens. Great choice for social photography, parties, weddings, e.t.c.
Summary: I can't believe how much the price of these has come down. Mine was £300 used a couple of years ago, get one quickly before they go up again. First and foremost this is a very fast lens of course.
Summary: When I first bought this lens I was delighted: sharp, fast and a fantastically tight depth of field which makes for some creative photos. Since then I have bought the Carl Zeiss 135mm f1.8 which is fantastic and makes one a little picky.
Conclusion: En mi caso lo utilizo con sensor APS-C (alpha 330), donde se comporta como si su distancia focal fuese de 75mm, o sea que me resulta un excelente lente para retrato, donde, a apertura total, obtengo un agradable efecto de "suavizado" en la región periférica.