Pentax Telephoto 55mm f/1.4 DA* SDM Autofocus Lens for Digital SLR

Model #21790

Pentax Warranty - USA Version
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Weight 13.23 oz (375 g)
Dimensions (dxl) Approx. 2.8 x 2.6" (7.11 x 6.60 cm)
Filter thread 58 mm


Diaphragm blades 9
Format compatibility Pentax Digital (APS-C)
Focal length 55 mm
Comparable APS-C Focal Length: 82.5 mm
Aperture Maximum: f/1.4
Minimum: f/22
Magnification 0.17x
Maximum reproduction ratio 1:5.7
Groups/elements 8/9
Camera mount type Pentax K
Angle of view 28.6°
Minimum focus distance 1.48' (45 cm)


Autofocus Yes
Tripod collar No
Image stabilization No
Expert Reviews
What digital camera.32818507
1 February 2010

An undoubtedly well-made Pentax prime, but does the image quality live up to the price-tag? Read the WDC Pentax SMC DA* 55mm f/1.4 SDM review to find out.

  • +

    Excellent ergonomics

  • -

    Fringing in MTF images

10 October 2012

We started this review by asking the question of whether or not the DA* 55mm F1.4 was really a star, or if it was just yet another expensive lens. The answer to the question is not definitive in either way. The lens is more of a stellar lens then not. So maybe it is almost a stellar lens.

  • +

    No distortion or vignetting, Well-built, Quick-shift focus, Weather and dust resistant, Excellent bokeh, Quiet SDM autofocus, Depth of field scale

  • -

    Some flare and chromatic aberration, Heavier than other Pentax 50mm lenses, Autofocus is significantly slower than screwdrive, Expensive for a standard lens

Slr lens and camera reviews.33034498
18 July 2009

Pentax smc DA* 55mm f/1.4 SDM is one of the latest addition to the company's growing portfolio of lenses specifically designed for digital SLR cameras. This is also one of the first KAF3 mount lenses in the company's potfolio.

17 May 2009

Gary Wolstenholme takes a close look at this short telephoto lens from Pentax. This 55mm f/1.4 lens from Pentax is designed to be used with their latest generations of DSLR cameras and sports a bright maximum aperture of f/1.4 and silent SDM focusing for around £600, which I feel is a little pricey...

  • +

    Excellent optical quality from f/2 onwards, Fast focusing, Weather selling, Low distortion and CA

  • -

    Limited compatibility with older Pentax DSLRs, Price, A little soft at f/1.4

20 December 2010

Does this wide aperture short telephoto lens for Pentax DSLRs justify the high price tag? Gary Wolstenholme investigates.

  • +

    Flare and ghosting is well controlled, only appearing in images taken under extreme conditions, such as lights shining straight into the lens when shooting at maximum aperture. A deep circular hood is provided, which does an excellent job of keeping unwanted light off the front element, further...

  • -

    Flare and ghosting is well controlled, only appearing in images taken under extreme conditions, such as lights shining straight into the lens when shooting at maximum aperture. A deep circular hood is provided, which does an excellent job of keeping unwanted light off the front element, further...

Photozone de.34752480
24 November 2009

The SMC-DA* 55mm f/1.4 SDM is a rather typical representative of the standard lens species - it is capable of delivering ultra-sharp results when stopped down a little but it's also fairly soft at very large aperture settings. Distortions and lateral CAs are not field-relevant.

Lenstip com.34355424
13 May 2009

Here we can practically rewrite everything we wrote in the Zeiss Planar 1.4/50 test summary. Pentax DA* 1.4/55 is definitely a good lens, but simply too expensive. A quick glance at the lowest shop prices shows, that we can get it for 2,500-2,700 PLZ.

  • +

    very good body quality,, fantastic image quality at the center of the frame,, very good image quality at the edges after slightly stopping down,, low level of chromatic aberration,, moderate distortion,, low astigmatism,, silent autofocus.

  • -

    image quality in maximum aperture range at the edges below expectations,, noticeable coma,, not too accurate autofocus,, some problems when working against bright light,, too high price.

User Reviews
B h photo.32817553
27 November 2016

I currently own three other lenses: 18-135 (kit lens), Tamron 70-200 f2.8 (which I really love) and the new Pentax 24-70 f2.8 but in all this my absolute favourite. In fact it's been on my camera body since I got it and I almost never use the others.

Photography review.34752477
19 April 2009

Severe back-focus on my K10D and I don't understand why Pentax changed the (in my opinion great screw-motor) with the slower SDM, the image quality (manually focused because the SDM AF shows back-focus) is great by the way.

  • +

    very sharp, great build and weather-sealing

  • -

    price is too high, back-focus problems on the K10D (I guess on the K100Ds too) and the accuracy of the SDM system

B h photo.32817553
4 January 2017

A very solid and beautifully built lens that mostly produces very nice photos. The colors and details are great, and it works very well for night photography. In particular, it handles nighttime street lights very well (much better than, say, the 40mm F2.8 limited, which produces very strange...

B h photo.32817553
19 November 2016

One of the best lenses I use on the Pentax system

B h photo.32817553
15 August 2016

great lens for aps-c, but on the k-1 you get slight vigntting at the corners on 90% of your shots.

B h photo.32817553
10 February 2016

I got this lens to use for portraits of family and for day-to-day photography (yes I know it's not a typical street-photo focal length).I find the images crisp and the lens responsive. It's heavy, but it seems worth it, and the manual focus is easy and satisfying to use.

B h photo.32817553
21 December 2015

It's bright, it focuses fast, and is fantastic for portraits and general photography. I try to restrict using it wide open to those circumstances where the main subject fills the frame. (As others have stated, bokeh can get a little odd when wide open...

29 September 2014

Great for portraiture. Using 1.4 throws the background out of focus concentrating on the subject. Ideal for low light situations. An ideal general use lens.

  • +

    Consistent Output, Durable, Easily Interchangeable, Professional, Quality, Quick Focus, Rugged, Sharp Focus, Strong Construction

B h photo.32817553
28 December 2013

I can now take indoor wedding photos without a flash! I have no downside for this lens.

B h photo.32817553
1 July 2012

This thing has an incredibly good image quality that should be expected of a DA* lens, and expected from the hefty price tag. The problem I'm having is that the autofocus just doesn't want to always work correctly.

Product Highlights
    Average Expert Score
    Average User Score
    In The Box
    • Pentax Telephoto 55mm f/1.4 DA* SDM Autofocus Lens for Digital SLR
    • PH-RBH Lens Hood for SMC DA* 55mm f/1.4 SDM Lens
    • O-LC58 58mm Lens Cap
    • Rear Lens Cap (B) for Bayonet Mount Lenses
    • Lens Case S90-100 (Soft)
    • 1-Year Pentax USA Warranty
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