Sigma 30mm F1.4 DC HSM "Art"
Specifications
The Sigma 30mm F1.4 "Art" features some of Sigma's latest lens technologies, including full-time manual focus override, silent HSM autofocus, and super multi-layer anti-flare coatings.
The barrel of the lens is made partially of metal and features carefully-machined components. Plastic elements used in the lens barrel include "Thermally Stable Composites".
| Lens Name | Sigma 30mm F1.4 DC HSM "Art" |
| Optical Formula | 9 elements in 8 groups. |
| Image Circle | APS-C |
| Image Stabilization | In-lens: N/A In-body: Pentax, Sony |
| Autofocus Type | Built-In silent HSM Motor |
| Field of View | 50.7° |
| Aperture Range | F1.4 - F16 |
| Aperture Blades | 9 (rounded) |
| Aperture Ring | N/A |
| Max. Magnification | 0.15x (1:6.8) |
| Minimum Focusing Distance | 30cm (11.8in) |
| Internal Focus | Yes |
| Full-Time Manual Focus | Yes |
| Filter Diameter | 62mm |
| Cap | Plastic, pinch type |
| Hood | Included, round |
| Case | Included (rigid soft case) |
| Diameter x Length | 74.2 x 63.3mm (2.9 x 2.5in) |
| Weight | 435g (15.3oz.) |
| Pentax Mount Designation | KAF3 |
| Weather Sealing | N/A |
| Price (US MSRP) | |
| Other Available Mounts | Nikon F, Canon EF, Sony Alpha, Sigma |
As one of Sigma's latest lenses, the 30mm F1.4 is compatible with the Sigma USB dock, a $59 PC accessory that allows users to calibrate the lens and upgrade its firmware at home. The USB dock is currently available for Canon, Nikon, and Sigma mounts. On April 11th, 2014, Sigma Japan announced that the USB dock will become available for Pentax and Sony mounts starting on April 25th.
The Sigma 30mm is eligible for the new Sigma Mount Conversion Service, through which the mount can be changed to one of the other available mounts. The fee for this service is $150; all work is performed by Sigma Japan and the service can be requested throguh your local Sigma distributor.
Compared to the Pentax 31mm F1.8 Limited
The Sigma 30mm is about 100g heavier than the Pentax 31mm. The two lenses are comparable in length, though the Sigma lens is about a centimeter thicker in diameter, which increases the filter thread size to 62mm, versus the 58mm of the Pentax lens. There is no practical difference in terms field of view, maximum magnification, and the minimum focusing distance. The Pentax lens covers the 24x36 mm film format, whereas the Sigma covers the 16 x 24 mm APS-C format.
Of course, the Sigma lens is just over half a stop faster than the Pentax lens, and it's less than half the price. It also has a silent autofocus motor rather than the traditional screwdrive mechanism found in the 31mm.
Compared to the Sigma 35mm F1.4
Being a full-frame lens, the Sigma 35mm is considerably larger physically than the 30mm: it's heavier by 230g and measures about 3cm more in length. It also has a larger 67mm filter thread. Since the Sigma 35mm has a longer focal length, its field of view is narrower than that of the 30mm. The minimum focusing distance of the 35mm is the same as that of the 30mm, which makes it slightly better for close-ups with its higher maximum magnification of 0.19x. The 35mm costs an extra $300 and features the same aperture and focusing mechanisms as the 30mm.
