PDN Product Review: Pentax DA* 55mm f/1.4 SDM

July 11, 2011

By Dan Havlik

The Pentax 55mm f/1.4 lens is small and light but looks more intimidating with its nearly 2-inch hood attached.

In recent months in these pages, I’ve looked at two stellar portrait lenses: the AF-S Nikkor 85mm f/1.4G and the Sigma 85mm f/1.4 EX DG HSM, which, at the time of this review, was available in Sigma, Nikon and Canon mounts. Since neither of those lenses is compatible with Pentax digital SLRs, I thought I’d round out my portrait photography product coverage by checking out the Pentax DA* 55mm f/1.4 SDM, a pro-level lens introduced a few years ago. (Hopefully, I’ll get to look at an Olympus portrait lens before 2011 is up, though I know of no new ones in the pipeline.)

I tested the DA* 55mm f/1.4 on a Pentax K-5, the company’s top-of-the-line DSLR, which I reviewed in the March 2011 issue of PDN. As I mentioned in that review, Pentax is seen as something of an underdog in photography circles and with good reason. A few years ago after it survived a messy merger with the Hoya Corporation, there was a rumor its camera division would be sold off. That never happened and it’s a good thing. The company continues to churn out high-quality imaging products including the 16.3-megapixel K5 and 40-megapixel 645D medium-format digital camera. (Editor’s note: Since this article was published in the print edition of PDN Magazine, Pentax was purchased by Ricoh. More info here.)

Add to that array of photographic hits the DA* 55mm f/1.4 SDM, a fantastic piece of portrait glass that should find a place in any serious Pentaxian’s camera bag.

If you’re thrown by the somewhat odd focal length of this lens, keep in mind that since Pentax has no “full-frame” DSLRs (at the time of this writing) the 55mm converts to 84.5mm when attached to the K-5, which uses an APS-C size image sensor.

That near 85mm length and fast f/1.4 aperture makes it a classic prime lens for portraits, still-life shots, and low-light photography in general. So while the lenses’ $799 price tag might sound high for a standard 50mm, compare it to the Sigma 85mm f/1.4 ($899) or the Nikkor 85mm f/1.4G ($1,699) and it stacks up quite well.

The black lens’ build feels solid, with a weather-sealed gasket to prevent moisture, dust, and dirt from seeping in. At the same, time the Pentax 55mm lens is fairly light, weighing just over 13 ounces without the hood. A quick word about the circular cone-shaped hood: it adds nearly two inches to the front of the lens, making it look either more professional or more conspicuous, depending on your perspective. Though I liked the hood and always try to use one to protect my best glass while reducing flare, there’s a stealth appeal to using this lens bare. It’s up to you.

Speaking of stealth, the Pentax 55mm f/1.4’s SDM (supersonic drive motor) keeps it whisper quiet so you won’t alert or scare shy subjects. I found the autofocus speed of the lens to be a notch slower than the Sigma and significantly slower than the Nikon. However, I liked Pentax’s Quick-shift Focus System, which let me override the autofocus just by twisting the rubberized focus ring to achieve manual lock. This was great for locking in focus in close-ups of flowers and other plant life. It also came in handy for beauty shots, letting me zero in on lips, eyelashes and other fine points to assure sharpness.

The lens did quite well even when shot wide open at f/1.4, producing an extremely shallow depth of field and beautiful blur behind my model while maintaining sharpness on her eyes. The lens uses rounded diaphragm blades, which helped produce natural looking circular bokeh in the background.

While you’ll probably want to use the Pentax 55mm mostly at f/1.4 for that distinct, extremely shallow depth of field look, the lens was probably sharpest at f/2.8, which still produced nice blurring in the background.

Shooting at f/1.4 is really what this lens is made for though and I was happy to see little to no chromatic aberration in the corners when I shot wide open. Pentax has placed Aero Bright coating on the internal lens elements to reduce ghosting and flare and it seemed to do the trick in backlit photos.

Overall, colors were rich and life-like and skin tones were warm and creamy; always a good thing when shooting a model or creating headshots for a client. The lens also worked well for macro photography, thanks to that vaunted f/1.4 aperture, which blew out the background and drew attention to the subject of my photos. I got some terrific shots of flowers but was disappointed that the lens’ minimum focus distance was only about 18 inches from the subject.


If you’re a Pentax photographer and are serious about portrait photography, the small and light Pentax DA* 55mm f/1.4 SDM could be the only lens you’ll ever need. This stealthy little sharpshooter helped us capture great portraits of a model and fantastic headshots of a singer, with beautiful background blur thanks to the lens’ fast f/1.4 aperture. Though it’s price tag might sound a little high for its focal length, the quality images you’ll capture with this lens are more than worth it.

Pentax DA* 55mm f/1.4 SDM

Pros: Excellent sharpness even when shot wide open; fast f/1.4 aperture creates beautiful background blur; superb performance in low light; virtually silent.

Cons: Autofocus speed slower than the competition; big lens hood is obtrusive.

Pricing: $799