Sigma 10-20mm f/3.5 EX DC HSM Autofocus Zoom Lens for Pentax

Model #202109

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Filter thread 82 mm
Dimensions (dxl) Approx. 3.4 x 3.5" (8.64 x 8.89 cm)
Weight 1.14 lb (520 g)


Minimum focus distance 9.4" (23.88 cm)
Magnification 0.15x
Groups/elements 10/13
Angle of view 102.4° - 63.8°
Maximum reproduction ratio 1:6.6
Diaphragm blades 7
Focal length 10 - 20 mm
Aperture Maximum: f/3.5
Minimum: f/22
Camera mount type Pentax K
Format compatibility Pentax Digital (APS-C)


Image stabilization No
Tripod collar No
Autofocus Yes
Expert Reviews
What digital camera.32818507
20 October 2009

Following in the footsteps of Sigma’s full-frame 12-24mm DG zoom, the 10-20mm DC version has a lot to live up to. What Digital Camera's Sigma 10-20mm EX DC HSM review sees if it lives up to the hype...

  • +

    Good all-round performance

  • -

    Nothing really!

Layers magazine.34752053
21 April 2011

A wide-angle zoom is definitely the way to go when photographing in this type of situation, whether it’s a car show, antique show, or anywhere that’s crowded or the subject is large, such as architecture.

  • +

    Quality; true cost of lens; construction

  • -

    Distortion at widest angles

The digital picture.34755376
2 March 2011

The well-built Sigma 10-20mm f/3.5 EX DC HSM Lens, at review time, is one of only a few lenses in the ultra-wide angle APS-C lens class to have a fixed maximum aperture. While f/3.5 is not what I typically consider wide/fast, the fixed maximum aperture allows a constant wide open aperture exposure...

12 August 2009

With a brighter f/3.5 aperture, the new Sigma 10-20mm lens will be better for low-light photographers. Priced at £440, does the new lens warrant the price tag?

  • +

    Very good resolution, Good build quality, Excellent value, Low levels of Chromatic Aberrations

  • -

    82mm filter size, Stiff manual focus ring

Pop photo.32824722
4 January 2010

Sigma's widest nonfisheye and fastest ultrawide zoom, the constant-aperture 10-20mm f/3.5 belongs to the EX family of sturdily built, optically gifted Sigmas. To control multiple forms of aberration, it uses three low-dispersion glass elements and four aspheric elements-the most of any Sigma.

Imaging resource.34355410
14 September 2009

Sigma has made some dramatic improvements in this constant-aperture version of the 10-20mm lens, and has made them where they count: at the 10mm end of the focal length spectrum, where (arguably) the majority will probably use this lens.

Practical photography.34754171
23 February 2017

Once the APS-C crop factor has been taken into consideration, the lens offers an effective focal range of 15-30mm.

Practical photography.34754171
30 September 2012

This Sigma wide-angle comes in at a very reasonable price for what it is and for its features. It’s also available for plenty of lens mounts. This lens is considered by some photographers as the benchmark for APS-C wide-angles, though our tests suggest this may not now be the case.

Photozone de.34752480
19 October 2011

The new Sigma 10-20 mm f/3.5 EX DC HSM leaves us with mixed feelings. The build quality of the lens is certainly excellent, distortion is a little high at the wide end (but excellent for the rest of the zoom range), there's also a fair amount of vignetting and CA, but that's typical for this lens...

Techradar uk.32817471
22 July 2010

Sigma's original 10-20mm f/4-5.6 ticked pretty much all the right boxes, and rapidly became a top seller for users of Canon, Nikon, Olympus, Pentax, Sigma and Sony bodies alike.

User Reviews
B h photo.32817553
25 January 2016

I shoot real estate photography for web and publication marketing. I have shot thousands of properties and over 50 magazine covers.I needed a lens with a wider view and as little distortion as possible. This lens did the trick.I use the Sony Alpha cameras.

4 August 2017

The lens has excellent clarity, and the extra items are wonderful. I love the travel bag! The crossbody style has an off-side fastener, which adds stability. Attached is an unedited shot with this lens and a Nikon 7200.

Imaging resource.34355410
24 September 2013

SLR Gear gave an accurate review regarding image quality. A little soft around the edges at the 20mm end, otherwise excellent. Most of the time you're at the wide end of this lens anyway and that's where it excels.

  • +

    Silent, fast auto focus, image quality at wide end, build, handling, low distortion for a fish eye, constant aperture essential for video

  • -


13 October 2010

This is an excellent lens for the money. At 10mm (F3.5( it was slightly soft but after 11mm the images were very sharp (F.4 and up). The quality and feel of this lens is really nice. It is a nice fit and nice price for my 7D.

  • +

    Light lens compared to my 16-35mm; nice color and decent low light performance; nice build quality

  • -

    Little soft at 10mm but sharpens quickly above 11mm.

20 February 2013

Sharp images across it's range. Quality build. Worth every cent...

20 October 2011

Beach Camera did a GREAT job in getting it to me QUICK!!! Thanks!

  • +

    Fast / accurate auto-focus, Strong Construction, Durable, Lightweight, Rugged, Consistent Output, Easily Interchangeable

7 days ago

The lens works exactly as I expected.

2 weeks ago

I use this on my D750 and it's a great little lens. I bought it for my trip to St. Augustine and it worked out well.

2 weeks ago

Great addition to my lens kit. Ticks all the right boxes.

B h photo.32817553
2 weeks ago

I used this the first time for some night photography. It worked pretty well. It seems a little noisier than my 18-270 pentax(Tamron?) lens. Took it to the high mountains last Sunday. Good results. Definitely soft corners at f3.5. I need more time for experimentation.

Product Highlights
  • Zoom Super Wide Angle
  • Two ELD Glass Elements
  • Fast and Silent HSM AF
  • Robust Construction
  • Made in Japan
Average Expert Score
Average User Score
In The Box
  • Sigma 10-20mm f/3.5 EX DC HSM Autofocus Zoom Lens for Pentax
  • Lens Hood
  • Front & Rear Lens Caps
  • Limited 1-Year North and South America Warranty Against Manufacturing and Workmanship Defects.
  • Limited 3-Year U.S.A. Extended Warranty Extension Against Manufacturing and Workmanship Defects.
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