Product Description
The Tamron AF 18-250mm f/3.5-6.3 Di-II LD Aspherical IF Macro Lens is a lightweight, compact and ultra high power zoom lens designed exclusively for digital SLR cameras with APS-C sized imager sensors. The focal length of this lens is equivalent to approx. 29-400mm in 35mm format. This lens offers an extreme zoom ratio of 13.9X, and is designed as the everyday "all-in-one" lens for digital SLR cameras, covering wideangle to long telephoto. The lens uses an optical system specially designed for digital SLR cameras. This resulted in the sufficient compensation of aberrations, including astigmatism, compactness, thanks to downsizing of the first group, a high zoom power, and optimum optical quality. >>>Key Features:Advanced Optical Design: One LD (Low Dispersion) glass element and one AD (Anomalous Dispersion) lens in the first lens group minimize on-axis chromatic aberration. Two hybrid aspherical lens elements serves to meet the desired compactness despite its 13.9X zoom power.>>> Internal Surface Coating to Reduce Ghosting and Flare: This lens features 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.;>>> Zoom Lock Mechanism:The Zoom Lock prevents unwanted barrel movement when carrying the lens/camera combination.;>>> Di-II Series Design: Design has been improved 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.
Product Details
- Brand: Tamron
- Model: AF018N-700
- Released on: 2007-01-15
- Dimensions: 2.90" h x 2.90" w x 3.30" l, .93 pounds
Features
- Advanced Optical Design
- Internal Surface Coating to Reduce Ghosting and Flare
- Zoom Lock Mechanism
- Di-II Series Design
From the Manufacturer
This breakthrough zoom covers the greatest range of any interchangeable lens in digital SLR photography—an astounding 14x wide-to-super telephoto ratio. That's the 35mm equivalent of a 28-400mm on an APS-C format DSLR. And it focuses down to 0.45m(17.7") over its entire range for dramatic close-ups. Remarkably compact and lightweight, its sharpness, resolution, and color accuracy are outstanding thanks to special lowe dispersion (LD) glass, high-tech molded aspherics, the latest multi-coating, and second-generation digital optimization (Di II). This is the most powerful zoom lens on the planet, and it literally puts the world at your fingertips, delivering crisp, flare free images of scenic vistas, sports, nature, and intimate close-ups of kids. It's the perfect all-in-one lens for traveling light and capturing the unanticipated.
AF 18-250mm F/3.5-6.3 Di II Highlights
Di II:
Lenses are designed for exclusive use on digital cameras with smaller-size imagers and inherit all of the benefits of our Di II products. These lenses are not designed for conventional cameras and digital cameras with image sensors larger than 24mm x 16mm.
14x Zoom
Capture your world with the longest-range zoom lens you can buy--experience the great power of a 14X zoom range with Tamron's 18-250mm--a single lens capable of shooting both wide angle and telephoto scenes. At nearly 14x, Tamron's lens is the world's most powerful zoom and delivers all the photographic freedom of this enormous zoom range in a single, compact lens.
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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.)
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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.
Anomalous Dispersion (AD) for Better Color Correction
Anomalous dispersion (AD) glass is a special type of optical glass that is used to achieve more precise control of chromatic aberrations, thereby enhancing overall imaging performance. Glass of this type provides an abnormally large partial dispersion ratio (amount of diffraction) for light of specific wavelength ranges (colors) within the visible spectrum. By combining AD glass having these special characteristics with elements made of normal glass having different dispersion characteristics, it is possible to control the dispersion factors of a specific wavelength. This enhanced level of control results in much lower levels of on-axis (central) chromatic aberration for telephoto lenses (or zooms used at tele-photo settings) and a significant reduction of lateral (peripheral) chromatic aber-ration for wide-angle lenses (or zooms used at wide-angle settings.)
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Aspherical Elements (ASL) Provide the Ultimate in Image Quality and Compactness)
Tamron uses several hybrid aspherical lens elements in many lenses bearing the Aspherical designation. These innovative optics allow us to achieve the ultimate in image quality, and at the same time produce lenses that offer remarkable zoom ranges in extraordinarily compact packages. By perfecting theses cutting-edge advances for series production, Tamron has advanced the state of optical design, and virtually eliminated spherical aberration and image distortion from the high-power-zoom series.Through the effective application of Hybrid Aspherical Technology, one lens elemen tcan take the place of multiple elements without compromising performance. This is what allows us to produce remarkably compact long-range lenses that deliver a uniformly high level of image quality at all focal lengths and apertures.
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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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