This is the large aperture standard lens for the NC series cameras. This lens makes manual focusing very easy, due to the bright image in the viewfinder and the shallow depth of field.
I heard reports from different sources about the coating of the front lens element being damaged. My lens was looking the same when I got it, but on closer inspection I realized that some oil or lubricant must have reached the rear side of the front lens element. I was able to take the lens apart, clean it thoroughly, and sucessfully put it together again. It now looks and feels like new again.
The performance of this lens is excellent when stopped down to 2.8 or more. Wide open, it is a little bit soft.