This is a telephoto zoom for exclusive use on digital SLR cameras that covers the focal length range equivalent to 85-310mm when converted to a 35mm format. The lens will allow D-SLR owners fitted with standard zoom lenses to enjoy with ease the professional-looking pulling and compression effects particular to telephoto lenses. Since the optical system is designed for exclusive use on digital cameras, the image circle is smaller, resulting in a compact package measuring 83.0mm (3.3), accepting a 52mm standard filter and weighing a mere 295g.
Macro and Out-of-Focus
The lens realizes an MFD (Minimum Focus Distance) of 0.95m (37.4) over the entire zoom range, the top level of the closest focusing distance among tele-zoom lenses. Since the maximum magnification ratio at f=200mm is 1:3.5, you can enjoy easy and convenient close-up photography. The Maximum Magnification Ratio of 1:3.5 is equivalent to 1:2.3 when converted to 35mm film format. Since the lens employs a nine-blade almost circular diaphragm construction, it provides naturally blurred background effects when a natural out-of-focus effect is desired. Such effects are done by using the shallow depth of field of a telephoto lens or in close-up photography, exploiting the outstanding specifications of 0.95m MFD over the entire zoom range and 1:3.5 maximum magnification ratio.
Optimized for digital SLR
The lens features an entirely new optical design for optimizing the overall distribution of optical power while reducing various aberrations to the absolute minimum and achieving remarkable downsizing at the same time. In addition, an LD (Low Dispersion) glass element is used to accomplish effective compensation of on-axis and lateral chromatic aberrations, a critical factor to enhance the optical quality in digital photography. As a result, the lens provides outstanding optical performance over the entire zoom range. The zoom lens uses a new optical system designed to confine the changing angles of incidences of light rays reaching the imager within a certain scope over the entire image field by considering the effects of variances due to zooming.
Enhanced peripheral illumination and Resolution
Peripheral light fall-off is minimized when compared with that of conventional lenses for film cameras, so images are uniformly bright from the center to the periphery. Since the lens is designed exclusively for digital SLR photography, it provides high image quality resolution, contrast and flatness of image field.
Internal Surface Coating and Design
By the employment 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 imagers themselves are reduced to the absolute minimum. 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 it stand out as a Di-II lens. The rubber patterns of the zoom and focus control rings have been improved at the same time to compliment the digital camera design style and to provide better handling.
Super Hybrid Mount
The lens features a super hybrid mount made of highly durable, lightweight engineering plastic precisely molded around a stainless steel core that is also highly durable. The Tamron lens mount portion weighs 70% less than a brass-made mount.
