Summary: I bought that lens for shooting a portraits. I needed small DOF and good separation from background. Pentax SMC DA 55 mm F/1.4 SDM have only small disadvantages: the first is size (but for 85mm eqiv. it is nothing) the second is purple fringing in background with open wide apertures (but probably because of that lens have such great bokeh! yeah!) and thirds (the most important) is flares in back-light shooting. Build quality is great. Speed of AF is enough for portrait.
Excerpt: Incredible lens. Optically is as good as it gets. This is my favorite lens and it has done wonders for me. At F 1.8 you can put this on a 24x36 and have no issues with sharpness or rendering. It truly is an amazing gem when it comes to resolving power.
Excerpt: When I bought the K-30 I knew from reviews and pictures on PF that I wanted this lens as I was interested in portraiture and night shots. It was my first prime after the kit 18-135 WR that came with the K-30. It has not disappointed me so far and rarely leaves my K-30 to the detriment of my 21 Ltd, 31 Ltd and 100 Macro WR. As a beginner in photography , I found this lens easy to use compared to the 31 Ltd.
Summary: This lens is such a huge improvement over the standard kit lens. When I first acquired my Pentax Kr, I was very happy with the camera as I got back in to photography after being away for 15 years. The Kr is my first digital SLR and I felt that I could achieve great quality pictures without film with a reasonably priced kit. After 18 months, however, I was finding that there was still a quality to my images, particularly of people, that was lacking.
Excerpt: This lens has produced some absolutely stunning images for me. I mean some real keepers. This is my first 1.4 lens so I may not be used to having that large of an aperture. However, with that said, when this lens focuses correctly, it is sharp as a tack. The autofocus seems a little slow, and it can be a little frustrating to get moving kids in focus. That may also be partly my fault because I am inexperienced shooting at those larger apertures.