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Sigma 18-50 mm F2.8 EX DC lens

By dpreview staff on Jul 20, 2004 at 06:13 GMT

Sigma has today announced a further extension to its range of DC lenses which are designed specifically for digital SLR's. The new 18-50 mm F2.8 EX DC has a very usable 18 mm wide angle (approx 28 mm FOV on a digital SLR) to 50 mm telephoto (approx. 2.7x zoom). Like all DC lenses the image circle produced by this lens is designed to be just the right size for APS size sensors and hence allows the lens to be more compact than it would otherwise be.

Press Release:

Sigma 18-50mm F2.8 EX DC

EX series, large aperture zoom lens designed specifically for use with digital SLR cameras

  • EX lens series denotes excellence of engineering and new technology.
  • Compact and lightweight zoom despite large F2.8 aperture.
  • Excellent correction for various types of aberration provided by one SLD (Special Low Dispersion) glass element and two aspherical lenses.
  • Super Multi Layer (SML) coating reduces flare and ghosting from which digital cameras tend to suffer.

F2.8 large aperture standard zoom lens designed specially for use with digital SLR cameras.
The characteristics of digital SLR cameras were taken into consideration when designing the lens power layout. The new advanced lens design corrects various aberrations. This lens provides the utmost correction against lateral chromatic aberration which is a serious problem for digital SLR cameras.

This lens is specially coated to get the best color balance whilst cutting down flare and ghost caused by reflections from the digital image sensor and lens. It has excellent correction for vignetting and superior peripheral brightness is ensured.

A Special Low Dispersion (SLD) lens and two aspherical lens elements provide excellent correction for all types of aberrations. The design produces a compact and lightweight, yet robust, construction with an overall length of 84.1mm (3.3in.) and maximum diameter of 74.1mm (2.9in.) and weight of 445g (15.6oz).

This lens has a minimum focusing distance of 28cm (11in.). It is equipped with inner focusing system. The non-rotating front lens element makes the lens suitable for using its petal-type lens hood and circular polarizing filters.

It is an ideal large aperture standard zoom lens for digital SLR cameras featuring APS-C size image sensor.

Sigma 18-50mm F2.8 EX DC lens specifications

Focal length 18 - 50 mm
Minimum aperture F22
Lens construction 15 elements in 13 groups
Angle of view 69.3° - 27.9°
Number of diaphragm blades 7 pieces
Minimum focus distance 28 mm (11 in)
Maximum magnification 1:5
Filter size 67 mm
Hood Petal-type hood
Dimensions (Dia x Len) 74.1 x 84.1 mm (2.9 x 3.3 in)
Weight 445 g (15.6 oz)

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