Providing a large aperture useful for low-light shooting and separating your subject from the background, the 50mm f/1.4 EX DG HSM Lens from Sigma is stand prime lens well-suited to full-frame and APS-C Pentax K mount digital cameras. The aperture ranges from f/1.4 to f/16 for control over light and depth-of-field. Also, the 50mm has an aspherical lens to control distortion and aberrations.
Featuring a HyperSonic Motor AF system, the lens has fast autofocus and can get a close as 17.7". A rounded 9-blade diaphragm also assists in ensuring that your have smooth out-of-focus elements. A front thread will accept 77mm filters and the lens comes with caps, a lens hood, and a carrying case.