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Articles > Lens news Oct 11, 2006  11:57
Tamron 18-250mm Di-II Zoom

Extending the tele-end of the popular 18-200mm All-In-One zoom to 250mm ultra telephoto makes this new 18-250mm Di-II Zoom the most versatile high power zoom lens available.

Tamron Co. announces at Photokina 2006 that the company has developed the AF18-250mm F/3.5-6.3 Di-II LD Aspherical (IF) Macro (Model A18), a lightweight, compact and ultra high power zoom lens designed exclusively for digital SLR cameras with APS-C sized imager sensors. The AF18-250mm F/3.5-6.3 Di-II LD Aspherical (IF) Macro is the ultimate high power zoom boasting the world’s greatest zoom ratio(1) of 13.9X, a milestone that Tamron, the pioneer of high power zoom lenses, has achieved by commanding its technologies to further expand the capabilities of high power zoom lenses.

13.9X, the Largest Zoom Power in the High Power Zoom Class, Covering an Easy-to-Use 28mm Wideangle to 388mm Ultra Telephoto (when converted to 35mm)
Tamron’s concept for the development of high power zoom lenses is "one-does-it-all, covering wideangle to telephoto" to satisfy customer needs for simplicity. Tamron has always kept this concept in mind when designing higher power zoom ranges. The question, “to what extent can the tele-end of a zoom starting with 18mm wideangle be extended in a lens designed for exclusive use with digital SLRs?" was posed and answered with the development of this ultra high power zoom lens possessing the world’s largest zoom ratio of 13.9X. It was not too long ago that the world of "wideangle to ultra telephoto film photography" could only be achieved with a combination of two zoom lenses; a 28-200mm plus a 200-400mm.

Advanced Optical Design Aimed at Optimum Power Distribution to Achieve Compactness and High Power
The optical system uses an LD (Low Dispersion) glass element and one AD (Anomalous Dispersion) lens in the first group to minimize on-axis chromatic aberration while achieving the 250mm ultra-tele focal length. In addition, suitable positioning of two hybrid aspherical lens elements serves to meet the desired compactness despite its 13.9X zoom power. In particular, Tamron’s engineers have pursued a thorough analysis of the optical configuration of the third lens group for optimum power distribution in the overall optical system. The approach has resulted in the sufficient compensation of aberrations, including astigmatism; the compactness, thanks to downsizing of the first group; the high zoom power; and optimum optical quality.

Revolutionary Minimum Focusing Distance of 0.45m (17.7") throughout the Entire Zoom Range Affords a 1:3.5 Macro Capability
The new zoom lens achieves a minimum focus distance of 0.45m (17.7") throughout the entire zoom range, top of the class capability among high power zoom lenses for digital SLR cameras, which results in a maximum magnification ratio of 1:3.5 at the 250mm tele-end.

Internal Surface Coating to Reduce Ghosting and Flare
Through the use of "Internal Surface Coatings" (i.e., multiple-layer coatings on cemented surfaces of plural elements) and new multiple-layer coating technology on ordinary elements, ghosting and flare due to reflections that occur when light enters through the front element and reflections caused by the imager itself are reduced to the absolute minimum.

Flower-shaped Lens Hood
A glare-reducing flower-shaped lens hood is included as a standard accessory. The special hood provides optimum shading of superfluous light rays that enter from the rectangular frame outside the image field.

New External Design of the New Di-II Series Conveys the Image of "High Performance, High Precision"
Improvements have been made to the external design by adding a gold-colored band between the focus and zoom rings to enhance the appearance and make the product stand out as a Di-II lens. Also, the black coating over the entire lens barrel creates a high-quality, sophisticated look. The rubber patterns of the focus and zoom rings have also been improved to complement the digital camera style and to provide better handling.
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