Pentax has launched a consumer-level standard zoom lens for its range of digital SLRs: the slightly unwieldily named smc PENTAX-DA 17-70mmF4AL[IF] SDM. The lens offers the useful equivalent zoom range of 26-107mm combined with a maximum aperture of F4.0 and Pentax' SDM system which uses a supersonic motor for focusing. The latter is only compatible with Pentax' latest DSLR offerings - the K20D, K200D, K100D Super and K10D. On all other bodies focus mode will default to manual focus.

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Press Release:

smc PENTAX-DA 17-70mmF4AL[IF] SDM A standard zoom lens offering approximately 4.1X zoom ratio, designed exclusively for PENTAX digital SLR cameras

HOYA CORPORATION is pleased to announce the marketing of the smc PENTAX-DA 17-70mmF4AL[IF] SDM interchangeable zoom lens, designed for exclusive use with PENTAX digital SLR cameras. This standard zoom lens covers the most frequently used focal lengths between wide-angle and telephoto ranges, and offers outstanding operability and well-balanced image description.

Major Features
1. Approximately 4.1-times zoom ratio covering from wide-angle to moderate-telephoto ranges
When mounted on a PENTAX digital SLR camera body, this zoom lens offers an approximately 4.1-times zoom ratio covering the focal-length range from 26mm wide angle to 107mm telephoto in the 35mm format. It offers the most frequently used focal lengths in day-to-day photography, making it ideal for a host of casual applications, including scenery, snapshot and portraiture.

2. Extra-smooth, extra-quiet SDM autofocus system
Thanks to the incorporation of the PENTAX-original SDM system driven by a built-in supersonic motor, this zoom lens offers exceptionally smooth, quiet autofocusing operation. When mounted on an SDM-compatible PENTAX digital SLR camera body,* the focus mode is automatically switched to SDM-assisted autofocusing. Because this zoom lens has been developed exclusively for SDM-assisted autofocusing, it is designed compact and maneuverable despite the incorporation of the built-in supersonic motor.
* This lens is compatible with the K20D, K200D, K100D Super and K10D (with Ver. 1.30 or later firmware installed) camera bodies. When mounted on other camera bodies, the focus mode is automatically switched to manual.

3. Exceptional image description
Incorporating two hybrid aspherical (AL) optical elements in its optics, this zoom lens assures exceptional image quality, while effectively compensating various aberrations.

4. Maximum aperture of F4 over the entire zoom range
Since this zoom lens offers a maximum aperture of F4 over the entire zoom range, it lets the photographer use higher shutter speeds to minimize annoying camera shake — especially in telephoto applications — or reduce the depth of field to intentionally throw the background out of focus.

5. Digital SLR-exclusive optical design
From lens coating and curvature to the positioning of optical elements, the optics has been meticulously designed to optimize the lens’s digital imaging characteristics. The image circle is perfectly proportioned to the camera’s image-sensor size.

6. Other features
(1) Minimum focusing distance of 0.28 meters over the entire zoom range
(2) Inner-Focus (IF) system to eliminate lens extension and retraction
      during focusing operation
(3) Quick-Shift Focus System for instant switching to manual-focus operation
      without any focus-mode changes, after the subject is captured in focus
      by the AF system
(4) SP (Super Protect) coating applied to the front surface to repel dust,
      water and grease

Pentax lens specifications

Lens name Pentax DA 17-70mm F4 AL [IF] SDM
Lens mount PENTAX KAF3 mount
Focal length 17 - 70 mm
Maximum aperture f/4
Minimum aperture f/22
Lens construction 12 groups 17 elements
Closest focus distance 28 cm (0.92 ft)
Angle of view 79° - 23° (with PENTAX D-SLR camera body)
Aperture blades 7
Filter attachment size 67 mm
Maximum Magnification 0.31 x
Dimensions 75 mm × 93.5 mm (3.00in × 3.70in)
Weight 485g (17.1 oz.) without hood; 515g (18.2 oz.) with hood