Abstract: Tamron SP AF11-18mm F/4.5-5.6 Di-II LD ASPHERICAL (IF)

Photography - Canon EOS, digital, nature
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Tamron SP AF11-18mm F/4.5-5.6 Di-II LD ASPHERICAL (IF)


NOTE - May 15th 2005 - There is now a full, hands-on review of this lens posted HERE


Today at Photokina Tamron announced a new addition to the selection of wideangle lenses for APS-C sized sensor Digital SLR Cameras. "APS-C" covers sensors with "multiplier factors" of 1.5x and 1.6x, which means most DSLRs except the Canon 1D and 1Ds series and the Kodak full frame DSLRs.

Current contenders are the 10-22 from Canon, the 12-24 from Sigma and the 12-24 from Nikon. The Tamron lens has reduced frame coverage, as do both the Nikon and Canon lenses. Only the Sigma is capable of covering a full 35mm frame and so can be used on any film or digital SLR.

The Tamron lens has a smaller zoom range than the others (1.64x vs. 2x) but still fills in the range from 11-18mm, which may be all users need since there are a number of 17-x and 18-x zooms already available. In fact Tamron have also announced an 18-200mm zoom (29-320mm full frame equivalent) for those who want to cover the maximum focal length range with the minimum number of lenses (though I suspect that like all extreme range zooms, there will be some penalty to be paid in terms of image quality). The Canon, Nikon and Sigma lenses are all quite expensive ($600 - $1000), so if this Tamron lens sells for a significantly lower price, the smaller zoom range may not be too significant. If it sells for $300 or less it will be a very attractive choice for APS-C sensor DSLR owners looking for a true wideangle.

Note that on the Canon 10D/20D/300D, an 11mm lens is equivalent to a 17.6mm lens on a full frame SLR. On a 1.5x sensor Nikon DSLR it's equivalent to a 16.5mm lens on a full frame 35mm SLR

The following information is taken from the Tamron press release:

Photokina, Cologne, Germany, September 28, 2004 - Mr. Morio Ono, President of Tamron Co., Ltd., announced the successful development of the SP AF11-18mm F/4.5-5.6 Di-II LD Aspherical (IF) (Model A13), a new high performance ultra wideangle zoom lens designed exclusively for digital SLR cameras using APS-C size image sensors.

SP AF11-18mmF/4.5-5.6 Di II


The new SP AF11-18mm F/4.5-5.6 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.

"Di (Digitally Integrated design)-II" is the designation Tamron puts on lenses designed for exclusive use with digital (APS-C size) SLR cameras, featuring optical systems optimized to meet the performance characteristics of digital cameras. Di (Digitally Integrated design)-II lenses cannot be used with digital SLR cameras using image sensors that are larger than that of an APS-C size imager, or with 35mm film SLR cameras.

MAIN FEATURES


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
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 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.


SPECIFICATIONS
Model Name A13
Focal Length 11-18mm
Maximum Aperture F/4.5-5.6
Angle of View 103- 75 (APS-C Size)
Lens Construction 15 elements in 12 groups
Minimum Focus Distance 0.25m (9.8") (throughout the entire zoom range)
Maximum Mag. Ratio 1:8
Filter Diameter 77mm
Overall Length 78.6mm (3.1") *
Maximum Diameter 82.2mm (3.3")*
Weight 375g**
Diaphragm Blade 7 blades
Minimum Aperture F/22
Standard Accessory Flower-shaped Lens Hood
Compatible Mount Canon AF, Minolta AF and Nikon AF-D
*Values given are for Nikon AF cameras.
**The value given is for Canon AF cameras.

NOTE - May 15th 2005 - There is now a full, hands-on review of this lens posted HERE


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