Sigma 30mm f/1.4 EX DC HSM lens

Infobox photographic lenses

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name = Sigma 30mm f/1.4 EX DC HSM
maker = Sigma Corporation
feat-is = No
feat-usm = Yes (not available with Pentax and Sony mount)
feat-sbf = n
feat-macro = n
application = interiors/portrait
flength = 30 mm
aperture = f/1.4 - f/16
groups = 7
elements = 7
diaphragm = 8
close-dist = 40cm / 15.7in
max-mag = 10.4
weight = 430g / 15.2oz.
max-diameter = 75.5mm / 2.9in
max-length = 59mm / 2.3in
filter = 62mm
hood = DiaPetal
av-horiz =
av-vert =
av-diag = Depending on sensor size
start = 2006
msrp =
category = Sigma lensesThe 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 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 assumes a crop factor of roughly 1.5, and therefore is "not" usable with on full-frame or 135 film cameras.

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).

For Nikon D40 owners, this lens is significant, in that it is the only available fast lens with a compatible autofocus system (as of August 2008).

Controversy

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.

External links

* [http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3300&navigator=6 Sigma 30mm F1.4 EX DC HSM page on the corporate website.]
* [http://www.pbase.com/cameras/sigma/30_14_ex_dc_hsm Sigma 30mm F1.4 EX DC HSM image samples on pbase.com]