Sigma 30mm f/1.4 EX DC HSM lens

From Wikipedia, the free encyclopedia

Sigma 30mm f/1.4 EX DC HSM

Key features
Maker: Sigma Corporation
Image stabilization: No (available only with Pentax K series, Konica Minolta, Olympus, and Sony bodies with sensor stabilisation)
Ultrasonic motor: Yes (not available with Pentax and Sony mount)
Short back focus: No No
Macro capable: No No
Application: interiors/portrait
Technical data
Focal length: 30 mm
Aperture (max/min): f/1.4 - f/16
Construction: 7 groups / 7 elements
# Diaphragm blades: 8
Close focus distance: 40cm / 15.7in
Max. magnification: 10.4
Physical
Max. diameter: 75.5mm / 2.9in
Max. length: 59mm / 2.3in
Weight: 430g / 15.2oz.
Filter diameter: 62mm
Accessories
Lens hood: DiaPetal
Angle of view
Diagonal: Depending on sensor size
History
Introduced: 2006
Retail info

The Sigma 30mm f/1.4 EX DC HSM is a wide-aperture photographic lens made by the Sigma Corporation, equipped with a hyper-sonic motor (HSM). The lens is produced in either Canon EF mount, Four Thirds System, Nikon F-mount, Pentax K mount, the SA mount, and the Sony/Minolta AF Mount varieties, all of the same optical formula. It ships with a removable petal-type lens hood (62mm diameter). The lens can only be used with APSC or Four Thirds digital SLRs, not on full-frame or 135 film ones.

Its large aperture allows for a shallow depth of field, allowing good isolation of close subjects. On APS-C sensor cameras, its field of view equivalent to that of a 46mm lens (Nikon, Pentax, Sony) or 48mm lens (Canon) or 51mm lens (Sigma) on 35 mm film is as close to a normal lens as makes no difference.

There is some controversy about the optical qualities of the lens; it seems to be optimized for very high central sharpness at wide apertures at the expense of edge sharpness or stopped down performance. This worries some owners, but strikes many as a very sensible design choice for a fast normal. It will mostly be used at wide apertures, where only a small crucial part of the subject will be in focus (such as the eye of a person). Thus any corner or extreme edges will not be in focus, and the resolution at those areas is irrelevant. For creative purposes, having a very sharp section indeed contrasting with the out of focus areas makes much more sense than a less sharp in focus area traded off for the capacity to take slightly better pictures of brick walls.

[edit] External links

This photography-related article is a stub. You can help Wikipedia by expanding it.