Introduced: 2009
Optical design: 6 elements in 5 groups
Lens mount: Sony A-mount
Covers: APS-C (23,5 x 15,6mm)

More info: 

https://www.sony.com/electronics/camera-lenses/sal50f18

Review: 

http://www.photographyblog.com/reviews/sony_dt_50mm_f_1_8_sam_review/

http://www.lenstip.com/168.1-Lens_review-Sony_DT_50_mm_f_1.8_SAM.html