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Sigma AF 30mm f/1.4 EX DC (Pentax K) Review / Test Report |
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Lens Reviews -
Pentax
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Page 1 of 3
Review by Klaus Schroiff, published May 2007
Special thanks to Jonas B. for providing this lens!
Introduction
The AF 30mm f/1.4 EX DC is one of Sigma's Digital Camera lenses
designed specifically for APS-C DSLRs. Its field-of-view as well as the high speed
resembles classic standard lenses (50mm) on full-frame camera. In Pentax land it
competes against the Pentax SMC FA 31mm f/1.8 Limited - a full format lens with a
2.5x higher price tag despite being somewhat slower regarding its max. aperture.
So the Sigma is obviously an attractive alternative at least on paper so let's see
whether it can match or beat the real thing ...
The construction feels very solid with the typical Sigma EX ("Excellence") finish
(crinkle style). The very broad, rubberized focus ring has a smooth action. The
front element does not rotate so using a polarizer is no problem.
The image above shows the Canon variant of the lens
The Sigma has no internal AF motor and
relies on a slotted drive screw operated by the camera. Consequently AF
operations generate a moderate degree of noise. The AF speed is very
fast on the K10D.
| Specifications |
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| Equiv. focal length | 45 mm (full format equivalent) |
| Equiv. aperture | f/2.1 (full format equivalent, in terms of depth-of-field) |
| Optical construction | 7 elements in 7 groups inc. 1 SLD (Special Low Dispersion), 1 ELD (Extraordinary Low Dispersion) and 1 aspherical element |
| Number of aperture blades | 8 |
| min. focus distance | 0.4 m (max. magnification ratio 1:10.4) |
| Dimensions | 77x59 mm |
| Weight | 430 g |
| Filter size | 62 mm (non-rotating) |
| Hood | petal-shaped, snap-on type (supplied) |
| Other features | - |
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