AF18-250mm F/3.5-6.3 Di II LD Aspherical [IF]
Model A18 and A18N II for Nikon*

Every photographer's dream come true – one lens that does it all!

It's the result of Tamron's continuing mission to develop these unique zoom optics to satisfy the desire of every photographer to be able to carry just one lens on their digital SLR and never risk missing a shot because they didn't have the right focal range available.

While conventional 35mm film cameras required two or more lenses to cover from the 28-388mm that this lens covers on a digital SLR, Tamron's new zoom is 13.9x. Amazing! 'The world's most powerful digital SLR zoom' delivers enormous photographic freedom in a single compact lens. The life of the digital photographer just got a whole lot brighter, with more chances of the shot you always dreamed of close at hand.

*Now available with a built-in motor for Nikon, making it compatible with models such as the D40.

MAIN FEATURES

This is the ultimate high power zoom lens boasting the world's greatest zoom ratio (when introduced in March 2007) of 13.9X, a milestone that Tamron, the pioneer of high-power zoom SLR lenses, has achieved by commanding its technologies to further push the boundaries of "mega-zoom" lens design.

To prevent the lens from becoming bulky, the design concept is based on the hugely popular Tamron AF 18-200mm F/3.5-6.3 XI Di-II LD Aspherical (IF) Macro. The AF 18-250mm zoom lens provides enhanced image quality from an expanded focal length to 250mm at the telephoto end together with an astounding 13.9X zoom power all the way from an effective 28mm, making it the world's greatest zoom ratio lens in its class. Yet the increase in size is confined to a mere 0.2mm more in its maximum diameter and just 0.6mm in overall length.

All of this is found in a lens that offers a 388mm ultra telephoto focal length (diagonal angle of view of 6°23') when converted to 35mm film format. It provides an overwhelmingly impressive telephoto effect, entirely different from the effect one attains at 200mm on conventional high-power lenses. The new zoom lens will satisfy the expectations of photographers that are used to the 300mm tele-end of Tamron's legendary AF28-300mm F/3.5-6.3 XR Di LD Aspherical (IF) when used on a digital SLR camera.

In 35mm film format terms, the new zoom lens covers 28mm wide angle to an incredible 388mm telephoto making this a "one lens-does-it-all" design that makes it a perfect travelling companion. There is no a need to carry around a variety of bulky lenses ever again!

Tamron engineers have used top-quality optical materials and internal lens coatings in advanced designs, to compensate for aberrations that would normally be present in such a high-power lens design. High image resolution, contrast, flatness of image field and great colour saturation are all made possible.

Despite its incredible compact size of 84.3mm long x 74.4mm wide, and weight of only 430g, the minimum focus distance is just 45cm throughout the entire zoom range. This allows for incredible close-up opportunities down to an original subject about the size of a business card.

DESIGN HIGHLIGHTS

Optimum optical system enables ultra-high-power zoom
Not an XR. Yet compact. While achieving the ultra telephoto capabilities of a 388mm lens**, this Tamron zoom features an extremely compact optical system. Unlike previous Tamron lenses, this lens optimizes the power distribution of the entire optical configuration without using XR glass, to achieve both ultra high-power magnification and compact size.

** Full-size format equivalent

High-quality digital images
This lens is designed exclusively for digital SLR photography, and provides high quality digital photos with outstanding resolution and contrast.

Packed with special glass materials
In addition to LD (Low Dispersion) glass that eliminates chromatic aberration and sharpens ultra-long shots, use of special glass materials such as Hybrid Aspherical Elements and Anomalous Dispersion (AD) glass achieve three goals in at once: increased magnification, compact size, and improved image quality.

Great for macro photos too: minimum focus distance = 0.45m (17.7")
Get amazing close-up shots with this digital SLR high-power zoom. The maximum magnification ratio of 1:3.5 (at f=250mm, MFD 0.45m) lets you fill the frame with a subject approximately the same size as a business card. You can easily and conveniently enjoy close-up (macro) photography of flowers, insects and more.

Counters ghosting and flare with new technology
Tamron has adopted various countermeasures against ghosting and flare, which are annoying factors in digital photography. “Internal Surface Coatings”*** and new multiple-layer coating technology on ordinary elements are employed to minimize reflections that occur when light enters through the front element. This reduces image-degrading effects caused by the image sensor itself.

***Multiple-layer coatings on cemented surfaces of compound elements.

Released in Australia March 2007.

SPECIFICATIONS

NOMENCLATURE

Digitally Integrated Design for DSLRs with small sensors

Di II lenses are designed for exclusive use on digital SLR cameras with APS-C-format image sensors. All Di II lenses are optimised to meet the performance characteristics of DSLRs, providing maximal resolution concentrated within the image field and assuring that light rays at the edges of the frame reach the sensor at favourable angles, thereby minimising peripheral light falloff.

In addition, all Di II lenses incorporate effective measures to increase light transmission and eliminate ghosting and flare, which are particularly noticeable with digital cameras. Tamron’s advanced multi-coatings are applied not only to external and internal lens surfaces, but also to surfaces in between cemented lens elements. Finally, Di II lenses are offered in a wide array that includes the focal length ranges most desired by DSLR shooters.

Low Dispersion

Chromatic aberration occurs when a lens element refracts different wavelengths of a ray of light – its rainbow colours – at very slightly different angles. This results in the 'colour fringing' that reduces the sharpness of an image. LD elements are made from special glass materials with extremely low dispersion indices (i.e. the refraction of a ray of light into rainbow colours is extremely narrow). Thus they effectively compensate for chromatic aberration at the centre of the field (on axis), a particular problem at long focal lengths (the telephoto end of the zoom range), and for lateral chromatic aberration (toward the edges of the field) that often occurs at short (wideangle) focal lengths. Although costly, LD glass materials result in clear, vivid image quality.

Aspherical

Tamron uses several hybrid aspherical lens elements in its lenses bearing the Aspherical designation. These innovative optics achieve the ultimate in image quality while producing lenses that offer remarkable zoom ranges in extraordinarily compact packages. These cutting-edge advances have advanced the state of optical design by virtually eliminating spherical aberration and image distortion from Tamron's high-power-zoom series.

As one hybrid aspherical lens element can take the place of multiple elements without compromising performance, remarkably compact long-range lenses can now deliver a uniformly high level of image quality across all focal lengths and apertures.

Internal Focusing

Tamron's internal focusing (IF) mechanism provides numerous practical benefits to photographers including:

• a non-rotating front filter ring that facilitates the positioning of polarising and graduated filters
• more predictable handling because the lens length does not change during focusing
• a much closer minimum focusing distance (MFD) throughout the zoom range
• improved optical performance by minimising loss of illumination at the corners of the image field (vignetting)
• suppression of other aberrations that become more troublesome at different focusing positions.

Specifications, design, product name and standard accessories may differ by country or area. While every effort has been made to ensure accuracy, these matters are subject to change by the manufacturer without notice or obligation.

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