Two entry-level DSLRs go head to head! the Pentax offers video and a new sensor while the Sony provides excellent Live View and a tilting LCD. Fight!
It’s the big difference between the K-m and the K-x – the move from a 10 MP CCD to a 12 MP CMOS sensor, both from Sony. It seems like a small change, but it completely changes the camera.
Highly praised in its day, the aging CCD sensor is now showing its age. Quality drops above ISO 1600 and it’s not capable of continuous imaging, meaning no possibility of Live View (the Alpha 330 "cheats" by using a second sensor for that).
The CMOS used in the K-x is similar to the one in the D300 and Alpha 700, introduced in 2007. Highly appreciated from its introduction for its efficiency in continuous imaging (making Live View possible, but also bursts of up to 8 fps on the D300), it made its mark above all for its sensitivity, the like of which had never been seen at the time on a "small" APS sensor. The sensor in the K-x even puts the high-end K-7 to shame!
A year after Pentax released its highly rated K-m, there is a new entry-level DSLR with the K-x. The two cameras are very similar, with the exception of one major change. The old 10 Megapixel CCD sensor is out, and a new 12 Megapixel CMOS sensor is in. So what we expect is a comfortable, pleasant-to-use little SLR with improved sensitivity. Let’s see if that’s what we get!
The K-x uses the same shell as the K-m. We notice only two changes – the delete button has been moved to make way for the Live View button; and the '?' button has been replaced by the “green” button Pentax likes so much. So the K-m’s guide is gone, but the interface is still exemplary, with quick access to the most common settings and well-designed menus. The construction is still just as light, the display remains at 230,000 pixels, but the handling qualities are amazingly good for a body this size thanks to the deep handgrip.
On the negative side, despite the return of 11-point autofocus as used on the K200D and previous models, there’s still no display of the focusing points in the viewfinder. So in multi-zone, it’s impossible to know what’s being focused on, and – as with the K-m – we advise you to use the center AF point only.
Certain kitschy details are also annoying, like the chrome strip around the top of the body and the extremely aggressive power indicator (fortunately, a custom function lets you turn it off). Finally, while we appreciate the discretion in the K-7’s shutter, the K-x fails in that department, with the shutter making an unpleasant clacking noise.
Among DSLRs, the K-x is up there with the best of the moment. Start-up is instantaneous, focusing is fast (but noisy with the kit 18-55 mm DA L lens), and so is image saving... provided you don’t enable the optical correction functions, which cause a delay of approximately three seconds when saving files! But since the same corrections exist in photo-retouching software, it may be better to leave them up to the computer. Burst mode is fairly fast, at 4.5 frames per second for nine JPEG images – an excellent result for an entry-level camera.
In Live View, as on nearly all SLRs (Sony being the exception), it’s much slower. Focusing is far from having the response of a micro four-thirds, and in practice the mode is unusable on moving subjects.
| Sensor||12 MP CMOS (APS-C)|
|Zoom||Kit Lens: 18-55 mm, f/3.5-5.6 DA L|
|Image Stabilization||Sensor Shift|
|Internal/External Memory||None/SD, SDHC|
|Sensitivity (ISO Range)||200-6400 (extension: 100-12800)|
|Power Supply||4 AA batteries|
|Dimensions/Weight||4.8”x3.6”x2.7”/20.5 oz. loaded|
The K-x is the first Pentax to use the excellent 12 MP CMOS sensor from Sony —undoubtedly a sign of chillier relations with Samsung, who had supplied the sensors for the K200D and K-7. So we expected spectacular progress. And we were not disappointed!
Up to ISO 1600, results were impeccable. At 3200 ISO, noise is visible in shadows, but it’s well contained and not a problem. Only at 6400 ISO does the quality really drop off, with noise visible on a 13x18 cm print. Those results compare with the Nikon D5000, the current benchmark for cameras using APS sensors, and will come as a real shock to anyone who’s tested Pentax products in the last two years.
The 18-55 mm DA L is an adequate kit lens, with good performance at the center and some loss of sharpness in the angles. It will be acceptable in many situations, but the most demanding users will want to replace it with a more high-end lens.
The K-x’s video mode has at least one advantage: It exists. Such is not the case with the Canon Rebel XS, Nikon D3000, or the Sony Alpha 550. However it’s still in the embryonic stage, since the autofocus is still too slow in live preview. In fact it’s disabled during recording, leaving you with manual focusing with lenses that allow focus touch-up, that is, which is not true of the kit 18-55 mm DA L. There’s simply no focusing at all, unless you switch to MF using the focus mode lever at the left of the lens mount.
So we won’t complain about the poor-quality monophonic sound recording or the use of the Mjpeg codec, which produces overly large video files.
You turn the camcorder on by pressing the Power button, which automatically opens the lens shutter, which covers a 10x optical zoom that starts at a focal length of 43mm – a bit narrow. We would have hoped for a slightly wider angle, even if the Sony HDR-CX520 does no better.
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The Pentax K-x is an ambitious new entry-level SLR. While the video function won’t appeal to anyone in their right mind, it’s a very pleasant camera to use and the image quality easily equals, and sometimes beats cameras costing twice as much.