The 120-400mm f/4.5-5.6 DG APO OS HSM Autofocus Zoom Lens from Sigma is a telephoto zoom lens for use with Pentax DSLR cameras. The lens features built-in Optical Stabilization (OS) for sharper photos, and a Hyper-Sonic Focus Motor (HSM) for quick and quiet autofocus.
Its optical formula is highlighted by three Special Low Dispersion (SLD) glass elements, which serve to correct color and preserve sharpness throughout the entire 3.3x zoom range of the lens. Its rear focusing system corrects for aberration fluctuations caused by focusing.
The lens, which is only eight inches in length and weights a mere 3.9 pounds, ships with a lens hood, a removable tripod collar, front and rear caps, and a carrying case. While it is not a true macro lens, its innate close focusing capability makes it a great use for capturing smaller objects including flowers -- without having to change to a dedicated macro lens.
Because most Pentax cameras feature in-body image stabilization, the lens provides you with the option of disabling the in-lens stabilization during use -- giving you the flexibility to use the image stabilization of your choice: in-body or in-lens. Owners of legacy bodies that do not have stabilization will find this option especially useful. Of course, you can disable the stabilization feature in both the lens and the body for those times when it is appropriate to do so, such as when you are using a tripod.
- Designed for use with full frame digital SLR cameras. May also be used with smaller APS-C size sensors with a corresponding effective increase in equivalent field of view to about 180-600mm with most cameras
- Offers Sigma's OS System (Optical Stabilization) allowing handheld photography even in low-light situations
- HSM (Hyper-Sonic Motor) ensures a quiet and high-speed auto focus
- Minimum focusing distance of 59" with a maximum magnification of 1:4.2
- Compact lens weighs only 3.9 pounds and is a mere 8" in length
- A lens hood, tripod socket (TS-31), front & rear lens caps, and carrying case are included with the lens