Pentax K-x review: Pentax K-x

7.8

Pentax K-x

$238 at Amazon

The Good

Very good noise profile; nice-size viewfinder for its class; relatively speedy.

The Bad

Doesn't display AF points in viewfinder; no HDMI connector; slow Live View autofocus; mediocre LCD; unreliable image stabilization.

The Bottom Line

A fast, inexpensive dSLR with better-than-average low-light quality, the Pentax K-x nevertheless has some flaws, such as unreliable image stabilization, to watch out for.

Photos:
Pentax K-x

Aside from the fact that it comes in too many colors to count, at least overseas, there's a lot to like about the Pentax K-x, an entry-priced dSLR with some sophisticated features you don't normally see in that price class. Continuing its tradition of aggressively priced dSLRs, the K-x model breaks the low ground by offering video capture support in a kit that costs less than $650. It's fast, with good photo quality and an excellent noise profile. And though there are a few things about it that really disappointed me, overall I think most shooters will like it for what it is: a flexible budget dSLR that delivers.

The camera body feels solid and well made, and it's a bit more compact than most of its competitors. However, like its predecessors, the K-x runs off four AA batteries, which make it heavier. Some people think AAs are a plus, others not so much. In practice, it means you can pack it with disposable lithium batteries that last a long, long time and you've got a choice between disposable and rechargeable, so I fall into the "plus" camp.

One of the camera's highlights, as well as its frustrations, is the viewfinder, which it inherits from its predecessors. On one hand, it's bigger, with slightly better coverage and more magnification than most consumer models. But though there are basic framing lines, in a bewildering move the camera doesn't display the autofocus areas. This is annoying for a couple of reasons. For one, if you shoot in complete autofocus, you have no idea which points the camera has selected in order to know if you need to switch out of that mode. If you use single-point AF, there's no reminder if you've moved it (without routinely looking at the LCD for confirmation). You do get an AF area indicator in Live View, with a couple of nice magnification options for manual focusing.

You can program Pentax's signature green button to reset the camera, choose the image settings, show a depth-of-field preview in the viewfinder, apply an effects filter, reset the autofocus point to center or override the file format settings. I really like Pentax's file override capabilities. You can define a behavior for any given scenario: the function depends upon whether the camera is set for JPEG, raw only, or raw+JPEG, and you can define the override you want for each as well as whether it's sticky or cancels after one shot.

Though it lacks a lot of the explanations and hand-holding features that some other entry-level models provide, the K-x's operation is relatively straightforward, incorporating many familiar conventions that point-and-shoot users are familiar with. Some aspects make a lot more sense than other implementations I've seen. For instance, the ISO screen lets you choose Auto or a fixed value, as well as the auto range it can choose from; the latter is usually buried in a menu somewhere.

Though there's a lot on it, the status screen provides an easy-to-scan display of most of your current settings. An Info button pulls up an interactive control panel that provides access to almost all the settings: image controls (saturation, hue, high/low key, contrast, and sharpness), cross processing, special effects, automatic HDR, shake reduction, metering, autofocus mode, metering, highlight correction, shadow correction, file format, resolution, compression, distortion correction and lateral chromatic aberration adjustment. Though it's a pretty packed display, it's easy to navigate and nothing's hidden in a place that you'll have trouble remembering.

The K-x includes a couple of interesting features, some unique to Pentax and some just new to the company. In addition to the traditional PASM exposure modes, Pentax offers a Sensitivity-Priority option (Sv), which automatically adjusts shutter speed and aperture as you scroll through a user-determined range of ISO sensitivity values. It's a nice alternative to the trial-and-error approach to finding the lowest ISO sensitivity that will deliver a desired exposure. There are also other veteran Pentax features like Catch-in Focus and the effects filter introduced with the K-7.

An auto High Dynamic Range capture feature combines three sequential exposure bracketed shots into a single JPEG. But unlike competing implementations from Sony, for example, it's not really effective as a simple way of producing better low-light images; shake reduction is automatically turned off and the camera doesn't seem to do any advanced alignment of the images. Even at a fast shutter speed there's significant camera shake, so you can only use it on a tripod. (For a complete accounting of the camera's features and operation, you can download the PDF manual.)

For the most part, the K-x is very fast. It takes 0.7 second to power and shoot, which is a bit slow but not bad. Time to focus and shoot in good light is a zippy 0.3 second, increasing to only 0.5 second in low light. Two sequential JPEGs run 0.4 second, with a slight bump to 0.6 for raw; its 1.2-second shot-to-shot time with flash is the only cloud in the K-x's speed sky, although Sony generally does worse. And typical continuous-shooting is a solid 4.2fps.

Other measures of performance aren't quite so rosy, most notably its image stabilization. For whatever reason--excessive mirror slap vibration, a stiff shutter, or simply a poor implementation--I had a lot more photos with camera shake, even at high shutter speeds and modest focal lengths, than I'm used to seeing these days. Furthermore, the LCD is fairly coarse, which makes it hard to accurately judge if the photos are sharp enough. It's also difficult to see in direct sunlight. And, as is typical for all but the Sony dSLRs, Live View autofocus is pretty slow.

Pentax K-x photo samples

The K-x is capable of shooting excellent photos. It has a very good noise profile for its class, including well-balanced noise reduction in JPEG files. You can start to see a bit of degradation of detail in shadow areas at ISO 800, but even at as high as ISO 1,600 I found the images quite acceptable. By ISO 3,200, the decrease in detail becomes obvious. Pentax rightfully considers ISO 12,800 (and ISO 100) an expanded mode, though I'd probably add ISO 6,400 to that as well. Though there's still usable detail at ISO 3,200, by ISO 6,400 noise and noise reduction artifacts are obvious, even when scaled down. I wouldn't recommend using ISO 12,800 as a rule, but this is actually pretty good, and not just for a sub-$800 model. You lose a lot of the shadow detail and there's obvious blotchiness, but the overall photo retains good saturation and it's more than acceptable for small Web use. However, the K-x maintains good color consistency across all the ISO sensitivity levels.

Pentax's 18-55mm kit lens doesn't display a lot of distortion at its widest, and the body's optional internal distortion correction does a pretty good job of fixing what little there is. On the other hand, the lateral chromatic aberration adjustment option didn't seem to fix much at all. It's worth noting that this is a generally nice kit lens, with an exceptionally close focus for its cohort.

Though the K-x's default Bright image setting produces a slight color shift over neutral, despite ostensibly bumping up only contrast and sharpness, it's not nearly as severe a shift as in Sony's comparable models and unlike Sony Pentax provides a Natural option. However, Pentax's automatic white balance normally tends to be on the cool side, which results in an overall color cast.

The video, however, is just so-so. It's only 24fps, shake reduction doesn't apply, and it's quite prone to the sensor wobblies. Exposure adjusts jarringly too frequently. On the other hand, it's the cheapest video-capable dSLR (at least at the time of this review), and it's fine in a pinch.

As long as you're willing to put up with some of its quirks, the Pentax K-x will probably deliver on your dSLR expectations.

Shooting speed (in seconds)
(Shorter bars indicate better performance)

Time to first shot

Raw shot-to-shot time

Shutter lag (dim light)

Shutter lag (typical)

Pentax K2000

0.7 

0.5 

0.5 

0.2 

Pentax K-x

0.7 

0.6 

0.5 

0.3 

Sony Alpha DSLR-A330/A230

0.4 

0.7 

0.6 

0.3 

Nikon D3000

0.2 

0.6 

0.8 

0.4 

Canon EOS Rebel XSi

0.2 

0.4 

1.2 

0.4