Amazing light sharp lens with 3D Pop
"This lens is a joy to use. It is ridiculously light, making it a great travel, streetscape lens. I have been using it for walkabouts in Porto, architectural detail, graffitti, ocean storms, etc so far but will take on trips together with the DA 70 for a light combo. I do have several other superb Pentax lenses, manual or AF, some great macro lenses, but for travelling and walkabout they are a bit too heavy. The HD DA 40 has some magic, and great colors and separation subject-background, when shot at f/4 or f/5. 6 (my favorite apertures), but is bitingly sharp after that. It is very sharp at first/2. 8, corners not being bad at all, and minimal vignetting. The round iris does make a difference from my other lenses, in well-tamed bacground light spots. Very happy with this lens, and of course, with Pentax in general."