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Constructed mostly of a hard plastic that resembles brushed aluminum, the camera body feels sturdy, as do the various buttons and dials. Unlike some inexpensive cameras, the Optio MX4 appears able to withstand a reasonable number of bumps and tumbles. With the battery and SD card installed, this device weighs a hefty 13.1 ounces. That's more than a typical 4-megapixel camera but less than most MiniDV camcorders.
The 1.8-inch LCD screen rotates 210 degrees vertically and 180 degrees horizontally, allowing you to position the camera for high- and low-angle shots, as well as self-portraits. There's no other viewfinder. Because the screen is attached to the top of the camera, it can block access to the top-mounted mode dial, power switch, menu button, and four-way controller, the last of which is used mostly for navigating LCD menus. It incorporates a center-placed OK button that can be tricky to select due to the small size of the controller. The onscreen menus are bright, distinctive, and well illuminated. That's especially important, given the generous selection of photo-specific, video-specific, and manual settings.
While the Pentax Optio MX4 is billed as a hybrid camera, its feature set is weighted toward photo capture. In addition to the fully automatic mode, you can use the mode dial to choose aperture priority, shutter priority, manual exposure, or a scene mode. The scene-mode selection gives you access to 10 options via the LCD. These include a night-scene setting that allows the shutter to remain open for as long as four seconds, a soft setting that applies the flare effect of a soft lens filter, and a panorama-assist setting that helps you stitch together overlapping photos. You can selectively save as many as 14 manual settings when the camera is turned off. All the photos are saved as JPEG files.
On the video side, you can select the resolution (640x480, 320x240, or 160x120), quality (three levels of compression), and frame rate (30fps or 15fps). There's also a time-lapse option that slows down the recording process to effectively speed up the recorded video by 2, 5, 10, or 20 times. You can create extraordinary time studies that are limited only by the available storage space on your SD card. All video recordings are stored as MPEG-4 files.
You'll also find some advanced features, such as a histogram display that analyzes light levels during shooting or playback to help you get better exposure. You have a choice of three metering options: spot, multisegment, and center-weighted. And the autobracketing option varies exposure, white balance, sharpness, color saturation, or contrast in a series of shots.
The 10X optical zoom is fully functional when you're recording video. With a maximum aperture of f/2.9 to f/3.5, the lens is relatively fast for its focal length range, which is the equivalent of a 37mm-to-370mm zoom on a 35mm-film camera. Pentax offers an optional L-WC17 conversion lens that extends the zoom on the wide end to the 35mm equivalent of a 27.75mm lens.
The Pentax Optio MX4 showed significant performance improvements over the Optio MX. For example, the MX had a wake-up-to-first-shot time of 6.4 seconds, which is well below average, even for an inexpensive digital camera. The MX4 reduces that time to 5.5 seconds, which is still too slow. Delay time between shots improved, moving from 3.4 seconds with the MX to 2.6 seconds with the MX4. When we turned on the flash, the shot-to-shot delay was about the same as before, with the MX pausing 3.8 seconds and the MX4 pausing 3.6 seconds.
With the Optio MX4's two continuous-shooting modes, the time interval varies according to the quality and complexity of the images. Using the standard continuous mode, we were able to shoot full-resolution photos continuously at 2.4-second intervals. Using the higher-speed continuous mode that's limited to two images at a time, the interval was reduced to 0.4 second.
The autofocus was accurate once it locked onto the target, though it proved to be slow, especially in low light. And while the two-speed zoom is smooth and relatively quiet externally, you can hear it on the video recordings when there's little or no ambient noise.
The 1.8-inch LCD screen provides a full 100 percent view. It's a bit small but reasonably detailed and sufficiently bright, even in sunlight. Adjusting its angle helped us avoid the glare of the sun. This camera freezes the image on the LCD screen while prefocusing, so it it's not a good choice for fast-moving subjects such as sports or children at play. Our action shots usually looked good, but we often felt we were shooting blind because of the sluggishness of the camera.We were able to produce some pleasing photos with the Pentax Optio MX4. Exposure and color saturation, as well as color accuracy, were usually spot-on when shooting exterior photos. Inside, the flash performed well most of the time but had a tendency to overexpose when shooting close to a subject or in macro mode.
Some of our ISO 200 shots exhibited a level of visual noise that pricier digital cameras limit to ISO 400. It wasn't objectionable but could be a consideration if you frequently shoot indoors with available lighting. Distortion and fringing were minimal. Overall, the Optio MX4 photos were a notch below what you would expect from an economy-priced 4-megapixel camera.
The Optio MX4 has improved its video quality over the original MX's but still falls far short of what a low-cost MiniDV camcorder can do. As with the previous model, there's a tendency for the image to tear horizontally when you pan the camera, especially at 640x480. Panning also causes compression artifacts to increase dramatically. And while the 30fps 640x480 setting is the closest to MiniDV video, that's where the camera becomes a storage hog. When matched with the best (lowest) compression setting, the included 32MB SD card stores only 1.25 minutes of high-quality video. If you plan to shoot a lot of video, consider purchasing a 512MB or 1GB SD card. Otherwise, you'll have to lower the quality settings, and your video will suffer accordingly.