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New Canon EF70-300mm f/4.5-5.6 DO IS USM zoom lens
Dennis Hissink : January 29th 2004 - 05:00 CET
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 Canon today releases the EF70-300mm f/4.5-5.6 DO IS USM telephoto zoom lens. A new triple-layered diffractive optical element (DO) has enabled Canon to produce a 70-300mm lens less than 10cm long. The lens also includes Canon's Image Stabilisation technology to dramatically reduce camera shake, compensating for approximately three stops in shutter speed without any perceptible increase in image blur. A virtually silent ultra-sonic motor (USM) gives the lens extremely fast autofocus. Full time manual focusing, a circular aperture diaphragm, and a zoom ring lock mechanism to fix the lens at the shortest focal length are all built in. The lens boasts image quality approximating that of Canon's L series professional lenses.
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 It is likely to appeal to professional photojournalists and serious advanced amateurs with a need to contain the size and weight of equipment carried.
DO Elements
This is the first DO lens to be released by Canon since it astonished the photographic community with the award winning EF 400mm f/4 DO IS USM: A lens approximately 26% shorter and 36% lighter than any lens of comparable specifications. Use of the new three-layer DO lens drastically reduces the overall length and weight of the lens system increasing the refractive power of each lens element and reducing the spaces between elements. Chromatic aberration normally associated with increased compactness was corrected by positioning the Three-layer type DO lens on the front lens side. This, coupled with the correction of spherical aberration through the use of aspherical surfaces, delivers high image quality and high levels of resolution and contrast, rivalling the performance of Canon’s legendary L-series lenses.
Zoom lock
The EF70-300mm f/4.5-5.6 DO IS USM features a zoom ring locking mechanism, locking the lens at its shortest total length. This helps to protect the lens from potential damage by preventing the zoom elements extending under their own weight. This might otherwise occur when the lens is mounted to a camera that hangs from a neck or shoulder strap.
Image Stabilisation
The lens incorporates Canon's renowned Image Stabilisation (IS) technology, compensating for approximately three stops without any perceptible increase in image blur when shooting static subjects or panning.
This vastly increases the range of circumstances in which hand-held photography is possible, limiting the need to carry a tripod. During major movement in a single direction, IS Mode 2 technology automatically determines that the movement is conscious panning and halts correction in the relevant direction, thereby preventing shake-return. The IS system automatically detects lack of movement / vibration to prevent operation errors when a tripod is in use. IS efficacy increases and lower overall size have been achieved through improvements in the moving contact sections of the IS lens barrel, the IS lens group barrel locking mechanism and the shake-detection gyro.
Fast AF
A rear focusing ring type USM, high-speed CPU and new AF algorithms combine to give the lens extremely fast auto-focusing. The ring-type ultrasonic motor (USM) converts ultrasonic vibrational energy into rotational force to deliver high-speed, high-precision, super efficient and virtually noiseless auto focusing, with good holding torque for rapid response and accurate stopping. Full-time manual override is featured, removing the possibility of damage to the autofocus mechanism during manual focus. The lens has a minimum focusing distance of just 1.4m throughout the entire zoom range.
Ideal for digital
Lens shape has been optimised and new coatings added to suppress ghosting and flaring. This makes the lens ideal for use with digital cameras that are more susceptible to reflections off the recording media than are film cameras. When fitted to digital cameras with an APS-C size sensor such as the EOS 10D, the lens will have an equivalent focal length range of 112 - 480mm in the 35mm format.
Attractive defocusing
Appropriate refractive and DO elements are combined to realise low distortion, high corner-to-corner resolution throughout the entire zoom range. As with all EF lenses, aperture is controlled with an EMD (electromagnetic diaphragm) for fast, quiet, highly precise control and the lens incorporates a near circular aperture diaphragm for beautifully pleasing background blur.
Working with EOS
The drive pattern of the lens is tailored to specifically match that of the latest EOS range, extracting maximum benefit from the lens’ speed advantage. The lens comes with a case LP1116 and an exclusive hood ET-65B for shading against unwanted direct light.
In harmony with the environment
In keeping with Canon's stringent environmental policy, only lead free glass is used in the lens’ optics. |
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