AF28-300mm F/3.5–6.3 XR Di VC LD Aspherical [IF] Macro
Model A20

High-power zoom lens designed for SLR cameras with full-size format, equipped with Vibration Compensation

This ultimate high-power zoom lens covers everything from wideangle to telephoto and macro. Tamron has developed its own anti-shake mechanism, a Vibration Compensator, featured for the first time in this lens. The A20 combines the convenience, comfort and versatility of a high-power zoom lens with the capability to reduce blur through camera shake on SLR cameras using either APS-C size or full-size format imaging sensors.

This lens covers a tremendous range of focal lengths – on a full-size format SLR camera, the range is from 28mm wideangle to 300mm ultra-telephoto. When mounted on a DSLR with an APS-C sized imager, it covers a 43mm wide angle to 465mm equivalent ultra-telephoto* (full-size format equivalent, in a diagonal angle of view of 5°20').

* The ratio used by Tamron to convert from full-size format to APS-C focal length is 1.55x.

MAJOR FEATURES

VC (Vibration Compensation) mechanism reduces lens shake
The proprietary VC (Vibration Compensation) mechanism developed by Tamron features a three-coil system using three pairs of driving coils and steel balls around the compensator group of the lens' optical system. Since the compensator lenses are supported with rolling friction of the balls, the response performance is enhanced and the construction is simple, which results in the compactness of the lens. The lens incorporate a highly accurate gyro sensor for detecting hand-shake, which, combined with a 32-bit RISC CPU, offers comfortable anti-vibration effects.
[Read more about Vibration Compensation below]

Outstanding design combines high zoom power, VC mechanism and compact size
The AF28-300mm F/3.5-6.5 XR Di VC integrates optical technologies that Tamron has accumulated as the pioneer and leader of high power zoom lenses in order to realize the desired compactness even while incorporating the VC mechanism. The optical system uses a number of lens elements made from special optical glass materials including XR (high refraction index) glass elements, GM (glass-molded aspherical lens) elements, hybrid aspherical elements, LD (low dispersion) glass elements to compensate for on-axis and lateral chromatic aberrations and AD (anomalous dispersion) glass element. The lens offers high contrast, high resolution performance and flatness of the image field as a one-does-it-all zoom lens designed to match the characteristics of DSLR cameras.

Revolutionary MFD of 0.49m (19.3") throughout the zoom range provides 1:3 macro magnification ratio
The AF28-300mm F/3.5-6.3 XR Di VC LD MACRO boasts an MFD (minimum focusing distance) of 0.49m (19.3") over the entire zoom range, a top-class closing focusing capability among high power zoom lenses for full-size format SLR cameras, which provides the remarkable maximum macro magnification ratio of 1:3 at the 300mm telephoto end.

Internal surface coatings minimise ghosting and flare
The use of internal surface coatings (i.e. multiple-layer coatings on cemented surfaces of plural elements) and multiple-layer coatings prevent reflections from lens surfaces, ghosting and flare due to reflections that occur when light enters through the front element. Reflections caused by the imager itself in the mirror box are reduced to the absolute minimum.

Ultra-high zoom power in a lightweight, compact design thanks to new mechanical devices
Tamron has reviewed the roles that respective barrel parts play in order to achieve the high power, compactness and light weight. As a result, dimensional increases are confined to a mere 17.8mm (0.7") in overall length and about 5mm (0.2") in diameter, when compared with the existing AF28-300mm (Model A061), despite the incorporation of the VC mechanism.

Zoom Lock mechanism for enhanced portability
The zoom lock prevents unwanted barrel extension when carrying the lens/camera combination over the shoulder.

Flower-shaped lens hood
A 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.

SPECIFICATIONS

* Values given are for Nikon AF-D models. The cosmetic design and specifications are subject to change without notice.

NOMENCLATURE

Digitally Integrated Design

Di is a Tamron designation that applies to lenses that have been optimised for digital capture using advanced multi-coating techniques and optical designs that assure excellent image quality across the entire picture field. Because of these characteristics, Di lenses provide outstanding performance on cameras with full-frame and APS-C format sensors as well as on 35mm film.

Extra Refractive Index

XR (Extra Refractive Index) glass can bend light rays at steeper angles, thereby decreasing the physical length of the lens while enhancing imaging performance by minimising optical aberrations. This has allowed Tamron to develop a line of shorter, smaller-diameter, lighter lenses without sacrificing lens speed, actually upgrading image quality compared to older designs.

XR glass is costlier than conventional glass but it yields enhanced optical power distribution, making possible many of the outstanding and innovative lens designs that bear the XR designation.

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.

Vibration Compensation

Tamron's unique VC mechanism uses a proprietary actuator and algorithms to deliver an extremely stable viewfinder image with excellent tracking. The mechanism employs three driving coils which activate the shake-compensating VC lens group electromagnetically via three steel balls. The VC lens elements are held in place only by contact with the steel balls, achieving smooth movement with minimal friction. The simplicity of this mechanical structure is also one of the secrets of Tamron's compact lens sizes.

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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