Lets review in optics area compact prime photo-lens Pentax HD Pentax DA 40mm f/2.8 for Pentax K mounts. It is notable by its small sizes and mass and small amount of lens elements. Its 40 mm focus is fixed ( with support of automatic and manual focusing ); diaphragm can be set in f/2.8 – f/22 range with use of 9 diaphragm blades, it is controlled by camera or manually; it is designed for Pentax APS-C optical sensors, with them it has 39 degrees field of view. Minimal focusing distance is 0.4 m, there is ability to attach 49 mm optical filters to it and it does not support optical image stabilization ( which camera perform by itself by sensor shifting, if it supports such function ). It has 5 lens elements in 4 groups, they all are covered with protective and anti-reflective multicoating. Its sizes are 63.5 ( diameter ) x 15.24 ( length ) mm, mass is 88 g, it is produced in 2 color variants : black and silver. Package contains : Pentax HD Pentax DA 40mm f/2.8 photo lens itself, frontal and rear caps, storage and carrying case and user’s guide. All in all, this a good photo lens with compact sizes, small mass, small glasses amount, automatic focusing and electronic diaphragm control ability, so it is good fit for videos recording ( especially if camera can perform image stabilization ) and photos making by novice and experienced photographers.