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| © Michael J. McNamara |
| IMAGE QUALITY: Class-leading resolution and sensor-shift IS aided the sharpness and depth of the New York-New York Hotel and Casino in Las Vegas. Shot with Pentax-DA 18-55mm f/3.5-5.6 AAL II lens, 1/40 sec at f/14, ISO 200. |
Sticking with the K10D's 11-point wide AF system was a good choice. With a 3x3 grid of cross-type sensors surrounded by a linear sensor, the array works with f/5.6 or brighter lenses.
In our Lab tests, the AF was very fast in bright light and sensitive in low light down to EV 0 (though slow there). In field tests, it tracked rapidly moving objects across a wide area of the frame. But it slows to more than 1 second at EV 2, and is sluggish at EV -1 -- not as fast nor as sensitive as the AF systems in several Canon, Nikon, and Sony DSLRs.
Pentax kept the K10D's viewfinder, with its 95 percent field of view and 0.94X magnification. You get a large, clear view and easy-to-read data display. And unlike nearly all of its competitors, the K20D has interchangeable focusing screens for specialty work, a bonus disappearing from some pro DSLRs.
On the metering side, we found the same, accurate 16-segment evaluative meter, centerweighted, and a 5-percent spot. In addition to these controls, the K20D also includes sophisticated white-balance, color-saturation, and exposure-compensation features. You can bracket white balance in either 3- or 5-shot sequences. The same choice applies to exposure compensation, with either 1/3- or 1/2-stop increments.
Live view
The CMOS sensor allows a feature that's becoming as common on DSLRs as autofocus -- live view. Especially handy for macro work or when shooting over crowds, this tool is sure to be put to new uses as its popularity spreads.
On the K20D, live view is easy to activate -- just turn the power switch around the shutter button to the third position. (You must first enable this function in the custom settings, or the same switch will turn on the depth-of-field preview.) Once live view is on, you can set the focusing system to auto or manual through a switch near the lens barrel. In live view, pressing the shutter halfway doesn't activate the AF -- if you try, you'll take a picture. Instead, you must press the AF button on the back of the camera. This mode has the typical delay between pressing the shutter and image capture, caused by the mirror moving into place for a split second. So forget tracking a moving target.
Live view's manual-focus mode gives you up to 8X magnification to fine-tune the focus. Custom menu items let you set the live preview screen to display either a grid or an outline of the area containing the 11 AF zones.
Better image stabilization
According to Pentax, the K20D has a sensor-shift mechanism similar to the K10D's, and offers up to 4 stops' advantage. But our tests confirmed that minor modifications and faster processors have improved the image-stabilization system by about half a stop over the K10D. Now, when shooting with a 200mm lens, you can expect a 2.5-3 stop advantage in shutter speeds compared to handholding the camera without image stabilization. With wider-angle lenses, the benefit decreases, and with longer focal lengths (or heavier lenses) the benefit may increase.
As with models from Olympus, the calming image-stabilization effect can be seen when the K20D is set to live view, a function that all image-stabilized lenses have in common.
Another noticeable improvement, especially for peace of mind, is that the sensor now locks more firmly into place when the camera is turned off.
Pentax understands that the versatility of a DSLR means that it might be exposed to adverse conditions. And the K20D is built to meet them. A tough plastic shell surrounds a rigid stainless-steel frame, and the body is shielded from moisture and dust by 72 gaskets -- including around the locking SD/SDHC door.
The controls are easy to reach and master, and menus are even clearer on the 2.7-inch screen, with its wide viewing angle and 230,000-dot resolution.
While changes to the electronics enable new features and controls, the modest burst rate of the K10D remains intact. In our tests, the K20D captured up to 38 Fine-quality JPEGs at 3 frames per second, or 14 PEF RAW files at 3 fps. At a slower speed, it captured 2.7 fps, allowing Fine-quality JPEGs to be shot until they filled a fast SDHC card. (Given the large image files from this 14.6MP camera, we wish there were a second slot for higher-capacity CF cards.)
One of the most innovative functions makes it easier to clean dust off the sensor. The camera identifies dust spots and enhances them on-screen, then reverses the screen horizontally and surrounds it with a graphic of the lensmount. Why? So when you turn the camera around to blow out dust you see the correct positioning.
Will all of these new capabilities, combined with the well-proven aspects of the K10D, be enough for the K20D to challenge the Canon EOS 40D? We think so, except at the upper ISO limits and in extremely low-light AF challenges. The price is competitive with -- or even below -- DSLRs in the nearby 12MP class, and it's built to outlast most lower-cost models.
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