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Sigma AF 12-24mm f/4.5-5.6 EX DG HSM - Review / Lab Test Report |
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Lens Reviews -
Nikon / Nikkor (APS-C)
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Page 1 of 2
Review by Klaus Schroiff, published April 2007
Introduction
The Sigma AF 12-24mm f/4.5-5.6 EX DG HSM is of three ultra-wide zooms made by Sigma - obviously
a primarily playing field for the company. The 12-24mm EX is a full format lens and as such it is unique
regarding its range. In fact there isn't even a (mass production) rectilinear SLR fix-focal this
wide. Quite an achievement! On an APS-C DSLR the specifications are not all that impressive
anymore but the field-of-view is still equivalent to a classic 18-36mm lens so even here it
keeps its ultra-wide character.
Due to the extreme design Sigma had to choose a very protruding front element
so there's no front filter thread by default. However, when attaching the lens
cap holder there is a option to mount a filter here (82mm). At 12mm this causes slight
edges shading so front filters can only be used from about ~14mm. There's a
gelatine filter slot at the rear of the lens (useful for color filters for B&W
photography).
Note: The image above shows the Canon variant of the Sigma AF 12-24mm f/4.5-5.6 EX HSM DG
The build quality of the lens is very impressive and among the best of what I've
seen from Sigma so far. The typical EX finish (smooth crinkle style) feels
very pleasant and the zoom and focus control rings operate very smooth and
well damped (focus ring only).
It doesn't really matter in this class but the lens has a pretty fast and near silent
HSM (hypersonic motor) AF drive with full-time manual focusing in single-shot
AF mode.
| Specifications |
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| Equiv. focal length | 18-36 mm (full format equivalent) |
| Equiv. aperture | f/6.8-f/8.4 (full format equivalent, in terms of depth-of-field) |
| Optical construction | 16 elements in 12 groups inc.4 SLD and 3 aspherical elements |
| Number of aperture blades | 6 |
| min. focus distance | 0.28 m (max. magnification ratio ~1:7.1) |
| Dimensions | 87 x 103 mm |
| Weight | 600 g |
| Filter size | 82 mm (non-rotating - see issues above) |
| Hood | built-in, petal-shaped |
| Other features | gelatine filter slot |
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