Shoot sharp and stay steady.
Pentax had to join the image stabilization club or face a shaky future. It chose to join in with its new K100D 6.1MP digital SLR ($620 street, body only), an *ist DS2 look-alike that's the first Pentax to feature a sensor-based shake reduction (SR) system. Unlike the lens-based IS systems on some Canon and Nikon lenses, this one should help reduce vibration-induced blur in photos taken with any new Pentax DA lens, plus all lenses with a Pentax mount.
We examined this camera's other features in our July 2006 issue, but we recently obtained a production version to see how well the new SR system reduced camera vibration. We also took a close look at claims Pentax made for improved image quality from its new processing engine and firmware, plus the newer versions of the Pentax Photo Browser and Photo Laboratory software that come with the K100D.
As we pointed out in July, the K100D has much in common with the Pentax *ist DS2, including a similar-resolution CCD sensor, nearly identical camera design and control arrangement, similar button placement, a large 2.5-inch LCD with easy-to-read fonts, and a nearly identical pop-up flash.
The biggest external differences appear to be the addition of an image stabilization switch on the back, plus some additional weight and size that can be attributed to the IS system. The four-way control button has also been slightly modified, and, of course, there's a new logo.
True to Pentax claims, we found some surprises on the image quality front and in the camera's performance, which don't have anything to do with the SR system. In the past, Pentax *ist cameras like the DS2 scored some of the lowest (though still respectable) resolution numbers in the 6MP DSLR class while turning in the lowest (that means best) noise levels at ISOs from 200 to 3200.
In our tests, the K100D's resolution scores jumped up a notch from the *ist DS2's 1,360 lines (Very High) to 1,520 lines (Extremely High), while noise levels started at Very Low at ISO 200 (instead of Extremely Low) and wound up at ?Moderate levels at ISO 3200 (instead of Moderately Low).
Apparently, Pentax's new processing engine backs away from the blurring filter that was used to minimize noise at the expense of resolution on the older *ist DSLRs. The company made the right move, as this camera's resolution has improved noticeably over the *ist DS2, especially at lower ISOs, and is more in line with 6MP Nikons and older Konica Minolta DSLRs that used the same sensor.
This time around, the camera's color accuracy fell just short of an Excellent rating. However, the differences between the *ist DS2 and K100D won't be noticeable in most photos.
Since we weigh resolution and color accuracy higher than noise in our overall Image Quality rating, the slight tweaks in processing parameters now earn the K100D a more solid Extremely High score at ISOs up to 1600. At ISO 3200, where most DSLRs get too noisy, the K100D squeaks in with Moderate levels and earns a Very High Image Quality rating.
Performance test results on the K100D showed some pluses and minuses. The viewfinder on the K100D and *ist DS2 are nearly identical when it comes to brightness, AF zones, and spotmeter delineation. But data display now includes a Shake Reduction icon on the far right side; AF mode, Scene Mode, and ISO sensitivity warning icons have been added to the left side. Formerly, the Picture Mode icons were spread out across, but now appear individually when activated.
The K100D earns an Excellent rating for viewfinder accuracy at 96% compared with 94% on the *ist DS2, a minor improvement. And it just squeaks by with an Excellent magnification rating at 0.85X, but that's down from the 1.04X on the *ist DS2.
More noticeable was the K100D's improved AF performance across the board, and especially in very low light-possibly another benefit of the improved processor in the K100D. Even in very bright light of EV 12-8, the K100D showed a 0.2 sec improvement over the AF on the *ist DS2, which it maintained all the way down to EV 2. At EV 1 and EV 0 there was a dramatic improvement to 1.51-1.81 sec compared with 1.71-2.2 sec on the *ist DS2. Best news? The K100D now focuses down to EV -1, although rather sluggishly in 2.5 sec.