SP AF17-50mm F/2.8 XR Di II VC LD Aspherical [IF]
Model B005

Even sharper, even easier wide-angle photography in low light using Tamron's high-speed, high-definition zoom and VC image stabilisation

This lens covers the extremely popular 17-50mm focal length range (equivalent to 26-78mm in the full-frame 35mm format*) making it extremely versatile. It delivers impressive sharpness and striking contrast over its entire range of focal lengths and apertures. At its maximum aperture of f/2.8 it produces beautiful images enhanced by shallow depth of field and excellent bokeh (i.e. smooth, natural transitions in the out-of-focus areas of the image).

Equipped with Tamron’s proprietary Vibration Compensation (VC) image stabilisation mechanism, which controls the effects of camera shake, this lens provides more opportunities for sharp handheld photography at the slow shutter speeds needed when shooting in low-light conditions (e.g. night or indoor scenes), dramatically enhancing the user’s level of photographic freedom.

* Using a conversion value of 1.55x.

VC (Vibration Compensation)

The Tamron Vibration Compensation mechanism employs a tri-axial system in which three driving coils move internal optical components within the VC lens electromagnetically, based on signals originating from three steel ball bearings. Because the VC compensating lens elements are held in place solely by contact with these bearings, smooth, virtually frictionless movement is assured, providing the stabilised viewfinder images and excellent tracking performance that are characteristics of VC photography.

VC mechanism incorporated with negligible increase in size

Tamron's SP AF17-50mm F/2.8 XR Di II LD Aspherical (IF) (Model A16) has been heralded for its combination of superlative optical performance and compact design. In this VC version, the compact size and ease of use have been retained while performance has been further enhanced. Tamron’s state-of-the-art VC mechanism has been incorporated without materially increasing its size and weight. As the VC lens elements move parallel to the image plane via electronic control alone, the structure of the VC mechanism is simplified, and the lens remains compact in size. As a result, pin-sharp handheld photography is possible under a vastly expanded range of photographic situations, with maximal convenience and ease of use.

MAIN FEATURES

1. All the advantages of a fast zoom lens are enhanced by Tamron’s proprietary VC (Vibration Compensation) image stabilisation mechanism

One of the greatest technical and creative photographic challenges is creating natural-looking images in lower levels of available light – for example, indoors, in deep shadow or in the evening. Photographers know that a 'fast' lens – one with a wide maximum aperture – extends their creativity in this respect, because the increased amount of light transmitted to the sensor at f/2.8 allows a longer shutter speed at the same ISO setting. Being able to capture an image handheld avoids the time and intrusiveness of setting up a tripod to stabilise the camera and increases the spontaneity and flexibility of shooting. It also allows the same scene to be captured at a lower ISO setting, resulting in less noise or 'digital grain' and thus a higher-quality image.

Another common solution to the problems of shooting handheld in low light is the use of flash to 'freeze' blur from camera shake. This not only results in a less natural-looking image but can also be intrusive during shooting.

Equipping a fast lens with VC technology extends the range of handheld shutter speeds, and all the consequent advantages, even further. Adding the versatility of a 17-50mm zoom range – and the ease of use from this lens' compact design – establishes new thresholds of naturalistic photographic expression.

And finally, even when shooting in light levels where handheld photography is generally possible, combining the fast f/2.8 maximum aperture of this lens with the VC image stabilisation permits dramatic blur from subject movements – in situations where setting up a tripod is inappropriate or even impossible.

2. Compact size with a filter thread of Ø72mm, while delivering both a large f/2.8 diameter and VC

To achieve the same anti-shake effect as the renowned VC mechanism incorporated into Tamron’s high-power zoom lenses – models B003 and A20 – the engineers had to enhance the VC unit itself, the mechanism that controls the optical image stabilisation system. Naturally, the addition of an image stabiliser tends to increase the size of a lens. As the this lens is a large-diameter f/2.8 zoom, the optical image stabilisation system is also relatively large compared with other VC models. Further research and development simultaneously reduced the size of the VC unit while increasing its torque; innovations in both manufacturing technology and production engineering improved the precision, weight, and strength of the lens’ components. Now this fast, compact zoom lens, with a filter thread of 72mm, incorporates both a large f/2.8 maximum aperture and an effective Vibration Compensation mechanism.

The Tamron SP AF17-50mm F/2.8 XR Di II VC is an extraordinarily complex lens to manufacture, but a joy to use.

3. Meeting the optical requirements of digital cameras, multiple elements of special glass enhance optical quality while maintaining compactness

• With its innovative use of XR (Extra Refractive Index) glass, Tamron has optimised the overall optical power distribution and reduced the size of the lens, while at the same time advancing the correction of optical aberrations.
• In addition, the optimal positioning of three compound aspheric elements (ASL) has enabled further shortening and compression of the entire optical system while maintaining outstanding imaging performance.
• Two LD (Low Dispersion) elements are also employed to make effective corrections for axial chromatic aberrations and chromatic aberrations due to magnification, a major factor in enhancing optical quality in digital photography.

The result: excellent image performance throughout the zoom range.

• Optimising the angle of light rays striking the image sensor
  To reduce the impact of changes in aberrations due to zooming, the optical design developed for this lens literally guides the angles of light rays entering from the centre to the periphery of the lens. This ensures that the light rays fall within a set range on the image sensor, enhancing image quality.
• Reduced fall-off of peripheral brightness
  The fall-off in peripheral brightness that limits resolution in wide-angle shooting is very well controlled, resulting in excellent image detail from the centre to the outer edges and corners of the image field.
• Superior resolution
  As an SP Di II class of lens, it delivers top imaging performance in all key parameters: it provides high resolution, high contrast, and excellent detail rendition.
• Countermeasures reduce ghosting and flare
  The latest BBAR (Broad-Band Anti-Reflection) multi-layer coatings reduce reflection from the lens, ensuring excellent performance in all photographic conditions. These coatings enhance light transmission in both short and long wavelengths. Internal coatings have also been applied to all the cemented surfaces of lens elements, providing sharpness, optimum colour reproduction and excellent colour balance.

4. Minimum focus distance of 29cm across the zoom range, with macro capability of 1:4.8

Even with its VC image stabilisation optical system, this lens delivers a minimum focus distance of 29cm (11.4") over the entire zoom range, enabling stress-free close-up photography. The maximum magnification ratio is 1:4.8** at 50mm.

**This lens enables photography of virtually the same range as when using a lens with a maximum magnification ratio of 1:3.1 on a full frame format camera, as the format of the APS-C size image sensors is smaller than 35mm film. For this reason, this lens is capable of filling the frame by capturing an area that is almost the same as an area covered by a lens designed for the 35mm format and providing the maximum magnification ratio of 1:2.3.

5. Streamlined, classic exterior design

A simple, classic design with a smooth silhouette ensures that this lens conveys quality and precision when mounted on any DSLR camera. Premium-quality textured paint provides a superb finish.

6. Zoom-lock mechanism, useful when carrying the lens/camera over the shoulder

Tamron’s zoom-lock mechanism prevents the weight of the lens barrel from extending the lens when carried on the camera pointing downward.

7. Flower-shaped hood is supplied with the lens to shield stray light

Provided as a standard accessory, the flower-shaped hood matches the rectangular shape of the image sensor to effectively block the interference of light rays entering from outside the borders of the image area, helping to ensure sharp, clear, flare-free performance.

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.

Super Performance series

Tamron SP (Super Performance) series is a line of ultra-high-performance lenses designed and manufactured to the exacting specifications demanded by professionals and others who require the highest possible image quality. In creating SP lenses Tamron’s optical designers put their foremost priority on achieving superior performance parameters – they are all designed to a higher standard with little regard for cost constraints. As a result, Tamron lenses bearing the SP designation feature impressive and innovative designs that have established an enviable reputation for excellence among those knowledgeable photographers that demand the very best.

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.

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.

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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