The AF18-200mm F/3.5-6.3 XR Di-II LD Aspherical (IF) MACRO is a high power zoom lens for exclusive use with digital (APS-C size) SLR cameras. It features an optical design using XR (Extra Refractive Index) glass in an innovative way in order to optimize the overall distribution of optical power throughout the entire zoom range. This design reduces various aberrations to the absolute minimum and achieves remarkable downsizing at the same time. In addition, three hybrid aspherical lens elements and two LD (Low Dispersion) glass elements are 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 quality in a multi-purpose zoom lens.
- Optical system uses special glass and is optimized for digital SLR characteristics in order to enhance optical quality in a compact design
The AF18-200mm high power zoom lens from Tamron features an optical design using XR (Extra Refractive Index) glass in an innovative way in order to optimize the overall distribution of optical power throughout the entire zoom range. This design reduces various aberrations to the absolute minimum and achieves remarkable downsizing at the same time.
- Optical design dedicated to digital SLR photography by optimizing the angles of incidences of light rays reaching the imager
The zoom lens uses an 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 from the center to the periphery, by considering the effects of variances due to zooming.
- Internal surface coating to reduce ghosting and flare
Ghosting and flare caused by aberrations are annoying factors in digital SLR photography, so Tamron has adopted various countermeasures against the problem including the employment of "Internal Surface Coatings" and multiple-layer coating technology on ordinary elements in order to minimize reflections that occur when light enters through the front element and to reduce image degrading effects caused by the imagers themselves.
- High power, yet compact and lightweight thanks to mechanical artifices
Complicated mechanisms are built in the compact body thanks to mechanical artifices. The lens is a multi-purpose zoom lens, yet excellent portability and ease of use are assured. A number of invisible engineering innovations required to downsize the lens, produce high precision parts and increase durability are incorporated in the AF18-200mm F/3.5-6.3 XR Di-II LD Aspherical (IF) MACRO since manufacturing this type of zoom lens with such complicated mechanisms inside was almost impossible with conventional manufacturing technology.
- External design conveys "High Performance, High Precision Image" as one of the Di-II series
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.