• Compact Fast Zoom with VC (Vibration Compensation)..
• Fast Constant F/2.8 Aperture..
• For use on APS-C size DSLR cameras..
• 11.4-Inch minimum focusing distance / 1: 4.8 Maximum magnification ratio..
• Internal Focusing..

From the Manufacturer --------------------- A masterpiece of innovative optical design, this compact, lightweight, high performance standard zoom (26-78mm equivalent) delivers a fast F/2.8 aperture over its entire focal-length range for maximum creative flexibility. To maintain critical sharpness when shooting handheld it includes VC (Vibration Compensation), Tamron’s state-of-the-art, tri-axial image stabilization system. Three compound aspheric elements, special LD glass, and BBAR coatings ensure superb correction, color fidelity, and freedom from flare. A minimum focus distance of 0.29m (11.4 inches ) offers exciting close-up rtunities. Compact & lightweight the AF 17-50mm is ideal for shooting on-the-go SP AF17-50mm F/2.8 XR Di II VC Highlights Di II Lenses are designed for exclusive use on digital cameras with smaller-size imagers and inherit all of the benefits of our Di products. These lenses are not designed for conventional cameras and digital cameras with image sensors larger than 24mm x 16mm. Vibration Compensation (VC) Handheld camera shake is the leading cause of blurry and unsharp pictures. Several leading companies now make lenses with built-in optical image-stabilization systems that sense the amplitude and direction of the shake and compensate by moving optical groups within the lens. Tamron’s exclusive new Vibration Compensation (VC) system that’s built into the Tamron AF28-300mm F/3.5-6.3 XR Di VC LD Aspherical (IF) Macro and the Tamron AF18-270mm F/3.5-6.3 Di-II VC LD Aspherical (IF) Macro lenses performs a similar function, but it executes it much more effectively due to its innovative breakthrough design * VC delivers blur free - handheld images for incredible results * VC mechanism employs a three-coil system * Lens element compensates for vibration using 3-steel balls (making movement quiet & smooth) * Exceptional images at slower shutter speeds – reduces the need for a tripod * Bring out contrast to motion & stillness * Eliminate the need to shoot with a Flash VC Off - VC On Aspherical Elements (ASL) Provide the Ultimate in Image Quality and Compactness) Tamron uses several hybrid aspherical lens elements in many lenses bearing the Aspherical designation. These innovative optics allow us to achieve the ultimate in image quality, and at the same time produce lenses that offer remarkable zoom ranges in extraordinarily compact packages. By perfecting theses cutting-edge advances for series production, Tamron has advanced the state of optical design, and virtually eliminated spherical aberration and image distortion from the high-power-zoom series.Through the effective application of Hybrid Aspherical Technology, one lens elemen tcan take the place of multiple elements without compromising performance. This is what allows us to produce remarkably compact long-range lenses that deliver a uniformly high level of image quality at all focal lengths and apertures. Achieve the ultimate in image quality with Asperical (ASL) lenses Extra Refractive Index Glass (XR) Extra Refractive Index (XR) glass can bend light rays at steeper angles, thereby decreasing the physical length of the lens while enhancing imaging performance by minimizing optical aberrations. This has allowed Tamron to develop a line of shorter, smaller-diameter, lighter lenses without sacrificing lens speed, and 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. XR glass, with its superior light-bending power, makes it possible to design a short-barrel lens with the same light-gathering ability (aperture value) as a long-barrel lens—even with a smaller lens diameter. By using this principle Tamron has been able to shorten the length of the entire optical system and produce lighter, more compact lenses of the same speed, and also to provide greater zoom ranges in lenses that are much more convenient to carry by hand. Special glass for better performance and more compact lens designs Super Performance (SP) for Discriminating Shooters 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. Low Dispersion (LD) Low dispersion (LD) glass elements in a lens help reduce chromatic aberration; the tendency of light of different colors to come to different points of focus at the image plane. Chromatic aberration reduces the sharpness of an image, but glass with an extremely lowdispersion index, has less of a tendency to separate (defract) a ray of light into a rainbow of colors. This characteristic allows the lens designer to effectively compensate for chromatic aberration at the center of the field (on axis), a particular problem at long focal lengths (the telephoto end of the zoom range), and for lateral chromatic aberration (towards the edges of the field) that often occurs at short focal lengths (the wide-angle end of the zoom range.) Low Dispersion (LD) Glass for Greater Lens Sharpness Internal Focus (IF) Internal focusing (IF) provides numerous practical benefits to photographers including a non-rotating front filter ring that facilitates the positioning of polarizing and graduated filters, and more predictable handling because the lens length does not change during focusing. Even more important, Tamron’s Internal Focusing (IF) system provides a much closer minimum focusing distance (MFD) throughout its entire focusing range. In addition, IF improves optical performance by minimizing illumination loss at the corners of the image field, and helps to suppress other aberrations that become more troublesome at different focusing positions Zoom Lock (ZL) Another original Tamron mechanical engineering concept is the Zoom Lock (ZL), a simple convenience feature that prevents undesired extension of the lens barrel when carrying the camera/lens unit on a neck strap..