Pentax K-x

Sharpness

As seen in the same-size image crops below, sharpness results are inconsistent, with wide variation based on shooting conditions. This is in part attributable to the extremely small aperture settings available with the kit lens: we expect to see sharpness fall as the lens is stopped down for any camera, and the K-x lens has a minimum aperture of f/40 at its long telephoto setting. More on how we test sharpness.

Image Sharpness and Chromatic Aberration

Focal Length:

18.0mm

35.0mm

55.0mm

Click blue squares to change sample crops below
f/3.5 f/9 f/22
f/4.5 f/11 f/22
f/5.6 f/14 f/40

Image Stabilization (2.02)

The K-x incorporates sensor-shift image stabilization in the body of the camera, so any attached lens reaps the benefits (versus Canon and Nikon SLRs, which use lens-based stabilization, with some lenses equipped with IS and others without). And there are benefits to be reaped here, in combatting up-and-down camera shake. When it comes to horizontal camera shake, on the other hand, the IS system was largely ineffective.

We test image stabilization by mounting the camera in a computer-controlled rig that produces programmed movement patterns at low shake levels (about what you’d find in a typical handheld shooting situation) and high shake levels (about the same as shooting one-handed, or while moving). We test at a variety of shutter speeds, moving the camera both horizontally and vertically, with image stabilization turned on and off. The thousands of test photos have their resolution levels analyzed using Imatest software, and the measured differences between results shot with and without IS lets us determine the system’s success.

In our low-shake testing, we found the image stabilization system make very little difference when it comes to horizontal shake, but produced a worthwhile advantage when the camera bobbed up and down.

The same pattern holds true when we cranked up the level of shake, with a consistent and meaningful improvement.

The stabilization performance of the K-x is nearly identical to the K2000, which makes sense. The Canon T1i, with its lens-based stabilization, was by far the best of the bunch.

The table below provides representative same-size crops from our horizontal stabilization testing.

Image Stabilization Comparison Table			Expand
	Low Shake IS Off	Low Shake IS On	High Shake IS Off	High Shake IS On
1/500
1/250
1/125
1/60
1/30
1/15
1/8