Camera Test: Pentax K-x

When knowledgable (and thrifty) photographers want a good deal on a budget SLR, Pentax has been the go-to brand for decades. To this day, you can still fi nd young photography students shooting with Pentax K1000 fi lm SLRs.

Does the company’s current entry-level DSLR, the 12.4MP K-x ($537, street, with 18–55mm f/3.5–5.6 lens), live up to the Pentax legacy? It sure does.

In features and performance, the little K-x stood up very well against its major competitors from Canon and Nikon. Starting with Pop Photo Lab tests, the K-x served up a Very High rating in overall image quality thanks to a Very High resolution score of 2125. That puts it on par with Canon’s 10.1MP EOS Rebel XS ($570, street, with 18–55mm f/3.5–5.6 IS lens) and Nikon’s 10.2MP D3000 ($550, street, with 18–55mm f/3.5–5.6 VR lens), which scored 2150 lines and 2100 lines, respectively. Like its two rivals, the K-x earned an Excellent Color Accuracy rating, again scoring in between them, with differences in results of the three so close as to be insignificant.

Noise, Autofocus, Speed

Noise suppression wasn’t terribly impressive at the lower end of its ISO range (both the Canon and Nikon beat it through ISO 400).

But at its highest ISOs, the K-x shined: At ISO 800 through 1600 (the Canon’s highest sensitivity), the Pentax edged ahead of the Nikon. While they both got Unacceptable ratings at ISO 3200, the Pentax showed significantly less noise (3.2) than the Nikon (5.5). And at ISO 6400—a sensitivity the Nikon doesn’t reach—it still did better than the D3000 did at ISO 3200.

The K-x’s autofocus tested well, too, with very strong performance in brighter light. At EV 12 through EV 6, it was equal to or faster than the two competitors. Though its AF was slower than the Canon and Nikon in dimmer light, it remained within 0.6 seconds of them even at its worst.

The K-x’s 11-point AF system offers a real improvement over the five-point system found in its predecessor, the K2000. It focused about 0.4 sec faster on average in the light levels below EV 4 in our lab tests. Plus, nine of the K-x’s AF sensors are cross-types concentrated in the center portion of the frame, for better sensitivity in both the horizontal and vertical planes.

Burst shooters will be glad that the K-x can capture up to 17 fullsize, highest-quality JPEGs at a rapid 4.7 frames per second. That makes it the fastest DSLR in this class, though not the most prolific burster. Canon’s Rebel XS can rack up 514 Large Fine JPEGs, albeit at a significantly slower 3 fps.