An ultra-wide-angle, Star-series zoom lens for use with K-mount digital SLR cameras, with a large F2.8 aperture over the entire zoom range providing exceptional optical performance
RICOH COMPANY, LTD. is pleased to announce the launch of the HD PENTAX-DA★ 11-18mm F2.8 ED DC AW. This high-performance, ultra-wide-angle, Star-series lens features a large F2.8 maximum aperture over the entire zoom range to deliver exceptional optical performance.
This ultra-wide-angle zoom lens delivers high-resolution, high-contrast images without blurring at the edges, and assures excellent imaging performance in high-grade digital photography, even at open aperture.
It has been developed as the latest model of the new-generation Star (★) series — a lens that provides exceptional image quality to be able to accommodate the super-high-performance digital cameras of the future.
With the introduction of this lens, the high-quality, high-performance Star series now provides a wide angle-of-view coverage —from ultra-wide angle to telephoto — with its compact models featuring a large F2.8 maximum aperture, which are exclusively designed for use with PENTAX APS-C-format digital SLR cameras.
In addition to an outstanding dustproof, weather-resistant construction, and -10°C cold-resistant construction, the lens provides a Focus Clamp Mechanism to lock focus at the desired focal point.
It also provides useful features to improve performance and dependability in harsh outdoor conditions: a space specifically designed for wrapping a heating device to prevent dew condensation, and a metallic frame structure to more effectively transmit the heat of the heating device to the lens. These devices greatly improve the lens’s operability when shooting landscapes and starry skies.
Lens construction
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.
Comparison of MTF
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.
Lens with a cable-type lens heater installed
Main Features
Large F2.8 maximum aperture
Despite its compact dimensions, this ultra-wide-angle zoom lens provides a focal length of 11 to 18 millimeters (equivalent to 17mm to 27.5mm in 35mm format) to produce magnificent, dynamic images. Since its maximum aperture is fixed at F2.8 over the entire zoom range, it delivers sharp, bright images of scenes with starry skies. Thanks to a minimum focusing distance of 0.3 meters, the lens also lets the photographer capture true-to-life close-up images by emphasizing the depth of field with an effectively defocused background.
HD Coating to enhance imaging power
This lens features high-grade, multi-layer HD Coating,* which reduces the average reflectance in the visible ray spectrum to less than 50% of conventional multi-layer coatings. It effectively minimizes flare and ghost images even in demanding lighting conditions such as backlighting.
* HD stands for High Definition.
Ideal design optimized for photography of landscapes and star-lit scenes
The unique Focus Clamp Mechanism allows the photographer to lock the lens’s focal point, even when the focus ring is rotated. This improves the lens’s operability in photographing such subjects as landscapes and star-lit scenes, which demand high-precision focusing during extended exposures. It also has special features for improved operability and versatility in outdoor shooting, such as a space for wrapping heating wires around the lens barrel to prevent dew condensation, without affecting focus-ring operation; and a metallic frame structure to more effectively transmit the heat of the heating device to the lens.
Dustproof, weather-resistant construction
Developed as an AW (All Weather) model, this zoom lens features a dustproof, weather-resistant construction to prevent the intrusion of water and dust particles into the lens interior. By pairing it with a PENTAX weather-resistant digital SLR camera body, this assures a highly durable, reliable digital imaging system that performs superbly in demanding shooting settings — even in rain or mist, or at locations prone to water splashes.
Other features
・Smooth, quiet AF operation using a DC motor
・Round-shaped, nine-blade diaphragm to produce a natural, beautiful bokeh (defocus) effect while minimizing the streaking effect of point light sources
・Quick-Shift Focus System to provide an instant shift to manual-focus operation after locking the subject in focus during AF operation by pressing the shutter-release button halfway down; usable at any time during AF operation
・SP (Super Protect) Coating to keep the lens’s front surface free of dust and stains
Specification
| Focal Length | 11-18mm |
|---|---|
| Equivalent to 17-27.5mm in 35mm format (when attached to PENTAX APS-C size DSLR cameras) |
|
| Maximum Aperture | F2.8 |
| Minimum Aperture | F22 |
| Lens Construction | 16 elements in 11 groups |
| Angle of View (Diagonal) | 104-76° (when attached to PENTAX APS-C size DSLR cameras) |
| Mount | KAF3 |
| Minimum Focusing Distance | 0.3m (0.98ft.) |
| Maximum Magnification | 0.10x |
| Filter Diameter | 82mm |
| Diaphragm Control | Fully automatic |
| Number of Diaphragm Blades | 9 |
| Rounded diaphragm （11mm:F2.8-4.5 18mm:F2.8-5.0） | |
| Tripod Mount | N/A |
| Lens Hood | PH-RBF82 (included) |
| Lens Cap | O-LC82 (included) |
| Lens Case | S120-150 (included) |
| Maximum Diameter x Length | approx. 90mm x 100mm (approx. 3.5in. x 3.9in.) |
| Weight | approx. 704g / with hood approx. 739g (approx. 24.8 oz./ with hood approx. 26.1oz.) |
| Temperature | -10°C～40°C (14°F～104°F) |
| Humidity | 85% or less (no condensation) |
Included Accessories: Lens Hood PH-RBF82, Lens Cap O-LC82, Lens Case S120-150, Lens Mount Cap K
Sample Photos (with PENTAX K-1 II)
Download/view full sized (6016x4000px) samples (on Google Drive)
