Product Description
The Tamron AF18-200mm high power zoom lens features an entirely new 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. A glare-reducing 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. It employs 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 from the center to the periphery, by considering the effects of variances due to zooming. Complicated mechanisms are built in the compact body thanks to new 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 new AF18-200mm F/3.5-6.3 XR Di-II LD Aspherical (IF) MACRO
Product Details
- Brand: Tamron
- Model: Nikon AF
- Dimensions: 4.00" h x 5.00" w x 6.00" l, 1.20 pounds
Features
- Since the lens is designed exclusively for digital SLR photography, it provides high image quality in terms of resolution, contrast and flatness of image field
- It employs 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 from the center to the periphery, by considering the effects of variances due to zooming
- Peripheral light fall-off is minimized when compared with that of conventional lenses for film cameras so that images are uniformly bright from the center to the periphery
- Complicated mechanisms are built in the compact body thanks to new 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 new AF18-200mm F/3.5-6.3 XR Di-II LD Aspherical (IF) MACRO
- Compatible w/ the following D-SLR cameras: Nikon D50, D70s, D80, D200, D2Xs, D2Hs & earlier models plus the Fuji S5 Pro & earlier models
From the Manufacturer
Tamron's original development of proprietary core technologies such as Aspherical element production, Multiple Cam Mechanism and Integrated Focus Cam design lend to the creation of the world's lightest, most compact 11x zoom lens made for digital SLR cameras.
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.
Extra Refractive Index Glass (XR)
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.)
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
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.
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