Pentax K-x Digital Camera Review$650.00
Lens & Sensor
The camera has an approximately 1.5x magnification factor, so the kit 18-55mm lens shoots like a 27-83mm lens on a 35mm camera. The three shots below show the zoom range from widest angle to maximum zoom.
The 23.6 x 15.8mm CMOS sensor has a gross resolution of approximately 12.9 megapixels, and an effective resolution of 12.4 megapixels. The sensor has a dust reducing coating in addition to a sensor shake system. If manual sensor cleaning is required, the Dust Alert feature lets you take a photo of a bright, solid-colored surface and get an image map showing where dust was detected.
The penta-mirror viewfinder is reasonably bright and comfortable, though eyeglass wearers will need to shift the camera a bit to see both the full scene and the information bar at the bottom of the screen. The field of view is approximately 96%, the magnification about 0.85x. The diopter adjustment is a slider at the top of the viewfinder, indented in the eyecup so it won't be moved accidentally. The diopter adjustment range is approximately -2.5 to +1.5m-1.
The illustrations below shows the viewfinder display, first the full screen, then an enlarged view of the information readout.
The LCD is an adequate but uninteresting 2.7-inch 230,000-dot display. LCD brightness can be adjusted along a 15-step scale, with a black-to-gray gradated strip displayed on screen while you move the slider. LCD color can also be adjusted to your liking, though this won't affect the actual color in the photos you shoot.
The illustration below shows the on-screen information display when shooting stills. It may not be the most graphically appealing arrangement, but it's very practical, providing easily legible readings for key shooting settings and readings plus reminders of digital filters and custom image settings in effect (so you're less likely to forget the funky setting you used for a previous shot and ruin the next one), and even at-a-glance reminders of the functions mapped to the four-way controller.
The movie mode info display provides a similar level of detail, including customized image settings along the right side.
As with most low-cost SLRs, there is no separate monochrome LCD to display shooting settings.
The built-in flash pops up about 3 inches from the center of the lens, a bit close when shooting with a long lens or hoping to avoid red-eye in portraits taken in dark environments. The strobe is quite small, with a very distinct hot spot in the center and relatively narrow coverage. Pentax gives the guide number for the pop-up flash as approximately 16 at ISO 200. Maximum shutter sync speed with the built-in flash is 1/180 second.
Shooting in Auto Picture mode, the flash will pop up automatically be default, but this can be defeated by changing the flash setting, an option too often missing in full auto mode. There is also a separate spot on the mode dial for auto shooting without flash, but this also disables the scene recognition feature ordinarily found in Auto Picture mode.
Pentax has enhanced the settings flexibility of the built-in flash compared to the K2000. Now, in addition to the auto and forced flash mode modes, you can use slow sync for capturing foreground subjects against a dark background, use trailing curtain sync to capture a trailing light effect behind moving subjects, and sync with an external wireless flash unit. Red-eye reduction is available in auto, manual, and slow sync modes.
Flash output compensation is available in a range of -2.0 to +1.0 stops, in 1/3 or 1/2 EV steps.
Shooting with an optional external flash makes P-TTL flash available, which fires a pre-flash to calculate the right exposure for the subject at hand before the photo is actually taken, and should produce a more accurate reading. With the AF540FGZ or AF360FGZ flash units, you can set the sync speed higher than the 1/180 second limit on the built-in flash. Wireless flash control is also available, using the built-in flash or one of the two listed above, along with a compatible external unit.
There is a single jack, located on the left side of the camera, with a proprietary connection for data and AV output. Unfortunately, the cable required to connect to a TV isn't included in the box, requiring an additional $14.95 purchase (if you can find the I-AVC7 cable at all). This was less of an issue with previous Pentax SLRs, but this one has video recording capability, so output to a TV set is a pretty mainstream activity. Also missing is an HDMI port for connecting to a high-def TV, despite the fact that the K-x does shoot in 720p video mode.
Unlike most SLRs, the Pentax K-x runs on 4 AA batteries (it comes with a set of Energizer Ultimate Lithium AAs).
Pentax claims that without flash you'll get 210 shots with a set of regular alkaline batteries, 1900 shots with pricey lithium disposables, and 640 per charge with rechargeable NiMH (nickel metal hydride) cells. In our initial testing, though, we blew through a set of regular alkalines much faster, and even the expensive lithium disposables didn't come close to 1900 shots. In early December, though, the company introduced a firmware upgrade primarily devoted to addressing just this problem. After upgrading the camera to version 1.01, battery life increased dramatically, approaching the manufacturer's initial claims. That said, we still recommend springing for a set of rechargeable NiMH batteries, since standard alkalines offer limited shooting capacity and the admittedly long-life lithium disposables go for about $15 for a set of four. Radio Shack is currently selling a package with four store-brand NiMH AAs and charger for $30.
Pentax also offers an optional AC adapter kit, K-AC84 ($65), with a battery-shaped coupler that fits in the compartment, which has a notch for the cable when the compartment door is closed.
The K-x uses SD/SDHC memory cards, the usual choice for compact digital SLRs.