Sigma 18-35mm F1.8 DC HSM Lens is the First Constant Aperture Zoom Lens

Sigma 18-35mm F1.8 DC HSM was announced recently.  The f1.8 aperture can be kept for the zoom range from 18 to 35mm. It is the first constanct aperture zoom lens. The lens uses an ultrasonic auto focus motor for fast and silent focusing. It is initially available in Canon EF, Nikon F and Sigma SA mounts. The new 18-35mm F1.8 DC HSM Art lens gives users a 27-52.5mm (35mm equivalent) on a 1.5x crop APS-C dSLR. The Super Multi-Layer Coating on the lens is used to reduce lens flare and ghost.

Sigma 18-35mm F1.8 Lens

Preview

Specifications

Maximum format size	APS-C
Focal length	18-35mm
35mm equivalent focal length (APS-C)	27-53mm
Diagonal angle of view	76.3° - 22°
Maximum aperture	F1.8
Minimum aperture	F16
Lens Construction	• 17 elements in 12 groups  • 5 SLD glass elements  • 4 glassmold aspherical elements
Number of diaphragm blades	9, rounded
Minimum focus	0.28m / 0.92ft
Maximum magnification	0.23x
AF motor type	• Ring-type Ultrasonic Motor  • Full time manual focus
Focus method	Internal
Zoom method	Rotary, internal
Image stabilization	No
Filter thread	• 72mm  • Does not rotate on focus
Supplied accessories*	• Front and rear caps  • Lens hood LH780-03
Weight	810g (28.6 oz)
Dimensions	78mm diameter x 121mm length  (3.1 x 4.8 in)
Lens Mount	Canon EF, Nikon F, Sigma SA