Ricoh adds a new lens to its 645 medium format lineup, the weather-resistant HD Pentax-DA645 28-45mm F4.5ED AW SR. Covering a 22-35.5mm equivalent range in full-frame terms, it uses 17 elements in 12 groups. It's Pentax's first optically stabilized zoom lens, with SR Shake Reduction technology that claims to compensate for camera shake for an additional 3.5 stops. The lens is dust- and weather-resistant, becoming available in August for a price of $4,999.95/£3,399.99.

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Press Release:

Ricoh Imaging Expands Pentax 645 Lens Line-up

HD PENTAX-DA645 28-45mmF4.5ED AW SR: An ultra-wide-angle zoom lens engineered to elevate the optical execution of the PENTAX 645 Medium Format Digital Cameras

Denver, Colorado August 4, 2014 Today, RICOH IMAGING AMERICAS CORPORATION announces the addition of the HD PENTAX DA645 28-45mmF4.5ED AW SR to the 645 interchangeable lens series. This ultra-wide-angle zoom lens is the latest in the PENTAX 645 line-up and is engineered for use with PENTAX medium-format, digital SLR cameras. Now Pentax 645 medium-format shooters will have a new high-quality lens to expand their distinct format shooting. 

This new lens provides focal lengths from 22mm to 35.5mm in the 35mm format, and is the first ultra-wide-angle zoom lens (approximately 1.6X zoom ratio) designed for use with our medium-format digital cameras. Its optics consists of 17 elements in 12 groups, including two high-performance aspherical elements and two extra-low dispersion elements. In addition, the PENTAX-innovated SR (Shake Reduction) mechanism has been incorporated into this exceptional lens, which effectively compensates for camera shake up to approximately 3.5 shutter stops.

Advanced, multi-layer, HD lens coatings are applied to optimize light transmission and minimize reflection. Paired with this with the PENTAX-exclusive, high grade Aero Bright Coating, this lens delivers the dynamic, super-high-resolution images that are only made possible by medium-format digital SLR cameras.

Eleven special seals are used to effectively prevent the penetration of dust and water into the lens interior offering superior dependability and durability under a wide variety of shooting condition empowering the photographer to capture various images ranging from those inside the studio to sweeping landscapes without concern.

'With the rapid adoption of the PENTAX 645Z, it is essential that we continue to address the needs of the professional photographer by providing premier lens choices. The launch of the PENTAX 28-45 mm lens reinforces our commitment to the future of medium-format photography' said Jim Malcolm, Executive Vice President, Ricoh Imaging Americas Corporation.

Pricing and Availability

The HD PENTAX-DA645 28-45mmF4.5ED AW SR lens will be available at retailers nationwide and at in August 2014 for a suggested retail price of $4999.95 

To learn more about the comprehensive lineup of Pentax products as well as other Ricoh Imaging products, please visit

HD Pentax-DA645 28-45mm F4.5ED AW SR specifications

Principal specifications
Lens typePrime lens
Max Format sizeMedium Format (645)
Focal length28–45 mm
Image stabilizationYes (3.5 stops)
Lens mountPentax 645AF2
Maximum apertureF4.5
Minimum apertureF32
Aperture ringNo
Number of diaphragm blades9
Aperture notesRounded blades
Special elements / coatingsHD and Aero Bright coatings
Minimum focus0.40 m (15.75)
Maximum magnification0.21×
Full time manualYes
Focus methodInternal
Distance scaleYes
Weight1470 g (3.24 lb)
Diameter99 mm (3.9)
Length152 mm (5.98)
Zoom methodRotary (internal)
Power zoomNo
Zoom lockNo
Filter thread82 mm
Hood suppliedYes
Hood product code38709
Tripod collarNo