Pentax K2000

Sharpness

We found the sweet spot for the 18-55mm kit lens when shooting at the 35mm focal length at f/11, where the lens delivered 1638 lw/ph horizontally and 2098 vertically.

In the charts below, we show actual-size crops taken from the test chart photos at each focal length. As you can see, at 18mm, there’s some noticeable chromatic aberration at the edges of the image, and the image softens noticeably across the board when the lens is stopped down to f/22, but the center is tack-sharp until that point. 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/32
f/5.6 f/16 f/40

Image Stabilization (4.64)

The Pentax K2000, like Olympus and Sony SLRs, has image stabilization built in to the body of the camera. This contrasts with the approach taken by Nikon and Canon, who build image stabilization into individual lenses, which are more expensive than similar lenses without stabilization. The benefit of the Pentax approach is that any lens you mount on the camera can take advantage of image stabilization… when there is an advantage. In our lab testing, we discovered that the Pentax system offers modest improvement where it counts the most, when shooting at shutter speeds of 1/30 second or lower. At higher shutter speeds, though, the results are hit-and-miss. In many instances, engaging the image stabilization system produced blurrier photos than turning it off.

Our image stabilization testing is conducted using a custom-made rig that precisely shakes the camera in a pre-determined pattern, under computer control. With the test subject mounted in the device, we shoot at two different levels of shake, taking multiple images at all shutter speeds between 1/500 and 1/8 second. Horizontal and vertical shake are tested separately. The resulting photos are processed using Imatest to determine image sharpness, and these results statistically analyzed to determine the effectiveness of the image stabilization system.

When subjected to a modest level of shake — roughly what we’d expect from an individual when holding the camera steady with two hands — we found that horizontal shake improvement was negligible at shutter speeds below 1/30 second. In the vertical direction, image stabilization offered an improvement at the fastest 1/500 second speed tested, but caused a loss of sharpness for the remaining range until we reach 1/15 second, where some advantage kicks in.

The second phase of our test increases the level of shake until it represents what you’d experience when trying to grab a shot one-handed, or when walking. Here we see a similar pattern to our low-shake test. At the highest shutter speed the sharpness is better with image stabilization turned on, but from that point on it’s causing a dip in image quality until we get to the 1/30 second level.

Bottom line, the Pentax K2000 image stabilization system is consistently inconsistent: that is, it sometimes improves sharpness, sometimes detracts from it, but in roughly the same pattern whether you are fairly steady or moving around quite a bit, and on both the horizontal and vertical axes. Our recommendation: turn the system on if you’re shooting indoors without flash or at night, but leave it off otherwise.

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