聚焦系统
| 最近聚焦距离 |
0.25 m |
| 光阑叶片数量 |
7 |
| 对角线视角（最大） |
103 ° |
| 最小光圈 |
4.5 |
| 最大光圈 |
22 |
| 焦距 |
11 - 18 mm |
SP AF 11-18mm f4.5-5.6 Di II LD Aspherical (IF) (Sony/Minolta)
A new high performance zoom lens designed for exlusive use with digital (APS-C) SLR cameras covering the ultra wideangle range
The new SP AF 11-18mm f4.5-5.6 Di II LD Aspherical (IF), an ultra wideangle zoom lens, is Tamron's first lens designed for exclusive use with digital SLR cameras using APS-C size image sensors. 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 a new 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.
Main Feature - Dedicated for Digital SLR Cameras
Through the employment of an optical design for exclusive use with digital (APS-C) SLR cameras, an ultra wideangle zoom lens with a focal length equivalent to a 17-28mm when converted to that of a 35mm full size film camera lens has been realized. Using this lens along with the digital SLR-dedicated AF18-200mm zoom lens introduced by Tamron simultaneously, you can enjoy creative digital SLR photography with a wide choice of angles of view.
Features an Optical System Optimized for Characteristics of Digital Cameras
In order to achieve outstanding optical quality, the optical system uses one element of HID (High Index/High Dispersion glass) to compensate for comatic and spherical aberrations; one LD (Low Dispersion) glass element to minimize on-axis (longitudinal) and off-axis (lateral) chromatic aberrations that are the greatest hindrance to high optical quality; one high-precision, large clear aperture, glass-molded aspherical element and two hybrid aspherical elements to thoroughly compensate for spherical and chromatic aberrations and distortion.
Optical Design Dedicated to Digital SLR Photography by Optimizing the Angles of Incidences of Light Rays Reaching the Imager - 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 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.
Outstanding Resolution - 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 above the focus ring 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.
