Designed specifically for pentaxs digital slr cameras the 55mm f14 da sdm lens is an ideal portrait or still life lens and offers an equivalent focal length of around 85mm in 35mm film terms which is perfect for flattering portrait shots the f14 maximum aperture produces soft graduation in out of focus areas of your images and also provides superb low light performance allowing the photographer to get the best out of available light sources the sdm focus system incorporated in the pent