Free Shipping on ALL Products

Support this site by shopping at the stores below or at our partner shopping page



 
 
Sigma Wide-angle Prime lenses for Pentax DSLRs

Lenses with focal lengths below 50mm are known as wide-angles. The shorter the focal length, the wider the lens becomes and the bigger the field of view you’ll capture. So if you’re stood in the same position, a wide angle lens can literally squeeze in more, which is useful whether you’re trying to photograph a large building from inside or out, a sweeping landscape view, or even just a big group shot. They’re invaluable when you can’t step back any further.

By squeezing more into your photos, wide angle lenses inevitably have greater distortion, especially towards the edges. This may not be that noticeable on natural landscapes, but can appear unflattering on portrait shots unless the person (or people) are placed in the middle of the frame. That said, this effect can also produce pleasing results and be used to exaggerate perspective – a popular wide angle technique is to get very close to a foreground subject so it appears large compared to the background. Wide angle lenses also have large depths of field, which means it’s easier to get lots in sharp focus from close-up to far away.

28mm is the most common wide angle focal length and can produce quite natural-looking results. Focal lengths below 20mm are generally known as ultra wide-angle and can produce quite extreme results. The most extreme of all come from fish-eye lenses which deliberately produce a highly curved result, while capturing an extremely large field of view.

As always, bear in mind any reduction in field due to your DSLRs sensor when choosing a lens. Pentax’s APS-C models have a reduction factor of 1.5x. So if you’d like 28mm equivalent coverage, you’ll need to fit them with an 18mm lens. Lenses with smaller f-numbers gather more light thanks to their bigger apertures, which makes them better in dim conditions and for minimising the depth-of-field. Bigger apertures however mean a larger, heavier and more expensive lens. Note Sigma's DC lenses are not compatible with full-frame bodies. For a full explanation of lens specifications and examples of coverage at different focal lengths, check out our Camera Labs Lens Buyers Guide.

 


Sigma 4.5mm f2.8 EX DC Circular Fisheye HSM
   
Focal length: 4.5mm
Aperture: f2.8
Lens mount: DA-mount
Equiv on APS-C DSLR: 7mm
Full-frame compatible: No
  Anti-shake: No
AF motor: HSM
Closest focus: 14cm
Filter thread: N/A
Lens hood: TBC
  Construction: 13 el. / 9 groups
Diaphragm blades: 6
Weight: 490g
Size (diam x length): 76x78mm



   
Sigma 10mm f2.8 EX DC Fisheye HSM

     
Focal length: 10mm
Aperture: f2.8
Lens mount: DA-mount
Equiv on APS-C DSLR: 15mm
Full-frame compatible: No
Anti-shake: No
AF motor: HSM
  Closest focus: 14cm
Filter thread: N/A
Lens hood: N/A (fixed)
Construction: 12 el. / 7 groups
Diaphragm blades: 7
Weight: 475g
Size (diam x length): 76x83mm


   
Sigma 15mm f2.8 EX DG Diagonal Fisheye

     
Focal length: 15mm
Aperture: f2.8
Lens mount: K-mount
Equiv on APS-C DSLR: 23mm
Full-frame compatible: Yes
Anti-shake: No
AF motor: requires AF motor in DSLR
  Closest focus: 15cm
Filter thread: N/A
Lens hood: N/A (fixed)
Construction: 7 el. / 6 groups
Diaphragm blades: 7
Weight: 370g
Size (diam x length): 74x65mm


   
Sigma 20mm f1.8 EX DG Aspherical RF

     
Focal length: 20mm
Aperture: f1.8
Lens mount: K-mount
Equiv on APS-C DSLR: 30mm
Full-frame compatible: Yes
Anti-shake: No
AF motor: requires AF motor in DSLR
  Closest focus: 20cm
Filter thread: 82mm
Lens hood: LH875-02
Construction: 13 el. / 11 groups
Diaphragm blades: 9
Weight: 520g
Size (diam x length): 89x90mm


   
Sigma 24mm f1.8 EX DG Aspherical Macro

     
Focal length: 24mm
Aperture: f1.8
Lens mount: K-mount
Equiv on APS-C DSLR: 36mm
Full-frame compatible: Yes
Anti-shake: No
AF motor: requires AF motor in DSLR
  Closest focus: 18cm
Filter thread: 77mm
Lens hood: LH825-03
Construction: 10 el. / 9 groups
Diaphragm blades: 9
Weight: 485g
Size (diam x length): 84x83mm


   
Sigma 28mm f1.8 EX DG Aspherical Macro

     
Focal length: 28mm
Aperture: f1.8
Lens mount: K-mount
Equiv on APS-C DSLR: 42mm
Full-frame compatible: Yes
Anti-shake: No
AF motor: requires AF motor in DSLR
  Closest focus: 20cm
Filter thread: 77mm
Lens hood:LH825-03
Construction: 10 el. / 9 groups
Diaphragm blades: 9
Weight: 500g
Size (diam x length): 84x83mm


   
Sigma 30mm f1.4 EX DC HSM

     
Focal length: 30mm
Aperture: f1.4
Lens mount: DA-mount
Equiv on APS-C DSLR: 45mm
Full-frame compatible: No
Anti-shake: No
AF motor: HSM
  Closest focus: 40cm
Filter thread: 62mm
Lens hood: TBC
Construction: 7 el. / 7 groups
Diaphragm blades: 8
Weight: 430g
Size (diam x length): 76x59mm


Sigma lenses for Pentax DSLRs
/ Guide to lens specifications / Main lenses page


All words, images, videos and layout, copyright 2005-2014 Gordon Laing. May not be used without permission.

/ How we test / Best Cameras / Advertising / Camera reviews / Supporting Camera Labs