Sony 50mm F1.4 Z Carl Zeiss T*

"With large aperture and single focal length this is the ultimate accessory for capturing brilliantly detailed pictures.  The eagerly anticipated SAL50F14Z (catchy hey) or  Sony 50mm F1.4 Carl Zeiss Planar T* to us laymen's, features an all new optical design so you can take sharp, clear, life-like images cross the full frame, even when light is poor.  With a maximum aperture of F1.4, you'll catch every ray of available light so you wont need to use a flash - great for twilight part shots and sunsets at the beach.  This lens is also really quiet and smooth with a super sonic wave motor that lets you lock-on fast to subjects such as wildlife without making any noise.

Tough an weatherproof the Sony 50mm F1.4 Z is ready for anything anywhere.  Its dust and drip resistant in aluminium, a high grade material that offers excellent durability and style. Designed perfectly to match Alpha cameras such as the SLTA99 & SLTA77.

Easy to use? Of course.  Set up shots your way with a focus hold button, direct manual focus and focus ring that doesn't rotate during autofocus.  Plus with a 9 blade circular aperture, you can indulge your creativity by exploring defocus, 'bokeh' effects and shallow depth of field."

So thats what Sony say, but Photography blog have given it 4.5 out of 5 stars.... highly recommended.  Read their full review here