This large-aperture, ultra-wide-angle zoom lens provides high resolving power and sharp contrast, and delivers exceptional imaging performance across the image field — features available only with new-generation Star-series lenses to accommodate the further advancement of digital cameras. With its dependable structure for use in demanding outdoor conditions and many innovative features, it can be used in a wide variety of applications, from landscapes and snapshots to star-lit nightscapes.
The newly designed lens badge signifies that this lens is the first new-generation Star-series model exclusively developed for use with APS-C-format digital SLR cameras. Its high-grade exterior design is identical with those of the latest lens lineup.
With its angle-of-view coverage from 17mm to 27.5mm (in the 35mm format), this lens delivers dynamic, breathtaking images. Despite its wide-angle optical design, a minimum focusing distance of 0.3 meters allows you to capture dramatic images with a beautiful bokeh (defocus) effect.
Along with the smc PENTAX-DA★ 16-50mm F2.8ED AL[IF] SDM and the smc PENTAX DA★ 50-135mm F2.8ED[IF] SDM, this lens completes the large-aperture zoom lens lineup, designed for exclusive use with APS-C-format digital SLR cameras. Combining outstanding imaging power with remarkable dependability for shooting in adverse conditions, this Star-series lineup provides a broad angle-of-view coverage, from ultra-wide angle to telephoto.
Technologies supporting exceptional imaging performance
For a lens to be designated as a new-generation Star-series model, it must clear a number of strict in-house standards. Here are some examples of outstanding optical designs and the advanced technologies which have realized them.
In order to effectively reduce various aberrations, the new lens incorporates an Extra-low Dispersion (ED) glass-molded aspherical optical element, in addition to two ED optical elements and two aspherical optical elements.
ED glass-molded aspherical optical element
This optical element combines an aspherical element’s ability to suppress spherical aberration with an ED glass’s ability to reduce chromatic aberrations. It contributes to the downsizing and weight reduction of the lens by minimizing the number of optical elements required in the optics, while satisfying demands for exceptional imaging performance required for the new-generation Star series.
HD Coating
After a thorough review of lens coating processes, PENTAX has developed a process which forms a high-precision coating layer very close to the theoretical values calculated during the design stage. This new-generation multi-layer coating is highly rigid and durable, and reduces reflectance to less than 50% that of conventional multi-layer coatings to effectively minimize flare and ghost images.
Dustproof, weather-resistant All Weather (AW) construction
The new lens features the dustproof, weather-resistant All Weather (AW) construction to prevent the intrusion of dust and water into the lens interior. By pairing it with a PENTAX dustproof, weather-resistant digital SLR camera body, the user can create a highly durable and dependable digital imaging system, perfect for use under demanding conditions such as in rain or mist, or at locations prone to water splashes.
Features assisting photography in the harsh environment
The new lens provides a range of features to help it respond to the tough demands made by professionals, including a focus ring designed for maximum operability even when the lens is wet or the photographer is wearing gloves; dependable operation at temperatures from -10°C to 40°C; and a highly rigid lens barrel structure.
It also provides user-friendly features to assist in photographing star-lit nightscapes, such as a Focus Clamp Mechanism to prevent the accidental shift of the focal point; and a groove specifically designed for installing a lens heater.
Focus Clamp Mechanism
When activated, this newly introduced, innovative mechanism lets you disengage the link between the focus ring and the focus lens group. This prevents the accidental shift of the focal point after you capture the subject in focus, improving operability in the shooting of star-lit nightscapes and astrophotography.
Unique design accommodating a lens heater
The lens exterior is designed with a lens heater groove to prevent dew condensation. To facilitate the installation of the heater, the lens is shaped fairly level, without a bump between the lens barrel and the focus and zoom rings. Also provided toward the front of the lens is a groove where the heater can be installed. Except for the optics, the lens has been constructed with metallic components for effective transmission of the heat generated by the heater.
