The SP AF11-18mm F/4.5-5.6 Di-II LD Aspherical (IF), an ultra wideangle zoom lens, is designed for exclusive use with digital SLR cameras using APS-C size image sensors (cannot be used on 35mm SLR's). The lens provides reliable performance in a compact size to meet the needs of digital SLR camera users pursuing creativity in wideangle photography. The lens uses an optical system specially designed for digital SLR cameras, in addition to the use of a glass-molded aspherical element having a large clear aperture, hybrid aspherical elements, and elements using such special glass materials as high index/high dispersion glass and low dispersion optical glass, for outstanding optical performance.
Optical System Optimized for Characteristics of Digital Cameras
The optical system uses one element each of HID (High Index/High Dispersion glass) and LD (Low Dispersion) glass to minimize on-axis and lateral chromatic aberrations that are the greatest hindrance to high optical quality. In addition, the lens uses a high-precision, large clear aperture, glass-molded hybrid aspherical element and two hybrid aspherical elements to thoroughly compensate for spherical and chromatic aberrations and distortion, in order to achieve outstanding optical quality.
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.
Enhanced Peripheral Illumination
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.
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.
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" (i.e., multiple-layer coatings on cemented surfaces of plural elements) and new 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.
Flower-shaped Lens Hood
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.
New External Design Conveys "High Performance, High Precision Image" as One of the New 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.
|Type of Zooming:||Rotation|
|Angle of View:||103 degrees - 75 degrees|
|Lens Construction:||15 elements / 13 groups|
|MFD (Minimum Focus Distance): ||0.25m (9.8")|
|Size (Diameter x Length):||3.3 in. x 3.1 in. (?83.2mm x 78.6mm)|
|Weight:||355g (12.5 oz.)|
|Max. Mag. Ratio:||1:8|
|Standard Accessory:||Flower-Shaped Hood|