Pentax K-x Review
BY: Adam Crawford, DigitalCameraReview.com Contributor
With its bearing in the upper entry-level market, the new Pentax K-x DSLR borrows its compact build from the K2000 (a.k.a. K-m) while sharing some of the features of their pro K-7. There are some unique functionalities behind the Pentax K-x, like HDR in-camera processing, a fast continuous shutter of 4.7 frames per second, and some great in-camera processing features. We'll discuss all this and more further on down.
The K-x also has some pretty standard features that are quickly becoming mainstays in the DSLR market, like a 12.4 megapixel APS-C sized CMOS image sensor, 11-point auto focus, 1280x720 HD video capture (at 24 fps, which is the standard speed for cinema motion picture capture), live view and an image stabilization system.
Another feature unique to the K-x is that it comes in four different colors, including black (our unit), white, and the harder to find navy and red. It certainly seems to have all the ingredients for a great camera. Its street price of $650 (body with 18-55mm kit lens) will get you some unique processing options, decent continuous shooting speed, HD video, 1/6000th sec. shutter speed max, and expandable ISO up to 12800. We took it through the paces, with the good folks at Digital Camera Review testing it in the lab and me in the field, and we have a comprehensive look at the Pentax K-x for you.
BUILD AND DESIGN
The design of the K-x is almost exactly identical to their entry-level K2000. The two cameras share the same dimensions of (WxHxD) 4.8x3.6x2.7 inches with only a minute difference in weight - the K-x weighs in at 18.2 oz. and the K2000 at 18.5 oz. With the same steel skeleton, rubber exterior, and similar button layout, there isn't much difference between these two siblings physically.
Ergonomics and Controls
The control layout of Pentax's K-x is nearly a spitting image of the K2000, minus a Live View button on the back of the camera. The DSLR body is very similar to all other Pentax creations, who have been known for creating sturdy DSLR bodies that don't feel chintzy, even with an affordable price tag on them. Often, cameras will suffer poor build quality when price is low, but not in the case of the K-x. It's a solid camera with a nice metallic/silver trim wrapping around the front of the camera and an excellent feel in the hand. The K-x doesn't have the ruggedized and weather-conscious build that the K-7 and K20D have, but it is created equally in terms of look and feel.
The K-x, as mentioned above, has the same exact layout at the K2000, minus the Live View button on the back, with an e-dial that lets you change shutter, aperture, EV and ISO when shooting. In image playback, the same control initiates image zoom. The shutter and power switch reside on the top panel, and other buttons include the Mode Dial, Exposure Compensation to change the exposure steps (or in Manual it sets the aperture), a customizable green button, a four way controller that helps you navigate the menu system, and an Info button that takes you to all the advanced features of the K-x without having to navigate menus to find things like metering and HDR.
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The K-x also has an AF/AE-L button that either locks exposure or autofocus, an Up button that deletes during playback or pops up the flash, and a focus mode lever to choose between AF or manual focusing. The K-x has a 2.7 inch LCD with a 230,000 dot resolution.. The K-x isn't much different from most other Pentax DSLRs, making it a small camera that is easily portable and feels substantially well crafted.
Menus and Modes
The Pentax menu systems haven't changed much at all, retaining a common looking layout that is layered with sub-menus. This is great if you are a Pentaxian - you'll find shooting with the K-x basically the same as all of their DSLRs, but from an outsiders' view, it may look a bit dated. However, there is a new user interface that I was completely pleased with.
As I mentioned just above, with the Info button you can quickly access important camera functions without having to rely on the sub-menu system, making it dramatically faster to get the settings you want without having to fuss with it. I've seen this in a few DSLRs over the years, including the Olympus E-3 that had a similar button that gave you access without menu diving. This is a welcome feature for a working photographer that wants pro access to their most used functions, but for the beginner to intermediate shooters out there, it gives you more control and easy usability when you're learning how to best optimize your camera use.
The Mode Dial offers your typical manual shooting options, including Pentax's proprietary Sv mode, as well as different Scene modes and Picture modes. Here's a run down of what you get on the K-x, starting with a total of seven different picture modes:
- Auto Picture: Automatically chooses the right capture mode for any given scene.
- Portrait: For portraits, automatically enhances for a bright skin tone.
- Landscape: Extends depth of field, and produces more saturated hues.
- Macro: Take pictures of small objects like flowers from close distances.
- Moving Object: Changes the drive mode from single shot to continuous shooting so you can capture all the action.
- Nice Scene Portrait: Take a low-light shot while the camera chooses the best settings.
- Flash Off: Forces the flash off.
There are ten different scene modes:
- Night Scene: Takes low-light shots while you're using a tripod for stability.
- Surf & Snow: Chooses the correct exposure for low-contrast images.
- Food: Saturates the images more to make food pop out.
- Sunset: For taking picturesque sunset images.
- Stage Lighting: For taking indoor images in a theater or concert.
- Kids: Set to continuous shooting for moving kids.
- Pet: Drive mode is also set to continuous to get a moving pet.
- Candlelight: For low-lit candle shots.
- Museum: Shoot in museums where flash is not allowed.
- Night Snap: Shooting without a tripod, but in a dark scene.
Movie recording mode captures wide-screen 16:9 aspect ratio 1280x720 HD video at 24 fps. Rounding out the mode dial are five more exposure modes.
- Manual: Allows you to choose shutter speed, aperture value, and many other parameters.
- Aperture Priority: Control aperture, while the camera chooses the best shutter speed.
- Shutter Priority: Choose shutter speed, while the camera choose the best aperture speed.
- Sensitivity Priority: Sets the shutter speed and aperture automatically, while you choose ISO sensitivity.
- Program: Sets both aperture and shutter speed, similar to automatic.
Display/Viewfinder
Where the K-x differs from the K2000 is that it employs Live View, allowing the user to bypass the viewfinder and compose shots on the LCD. The K-x has a 2.7 inch 230,000 dot wide-angle view LCD that is pretty much a basic size and resolution as far as DSLRs go. It also has a mirror-box pentamirror viewfinder with a 96% area of coverage, which is pretty nice for this class of camera. The viewfinder has a diopter adjuster for people who need to make adjustments for their vision.
Although the K-x has Live View functionality, there are a couple of things that make it somewhat difficult to work with. First, it is extremely hard to get the camera to focus on objects quickly when using Live View, especially in low light, and the second is that it drains the battery almost completely when in use. As Pentax's Live View comes with a price, it also helps photographers to compose shots are strange angles, and with patience, you can get the shot, but I have certainly seen better renditions of Live View with Olympus, Nikon and Canon branded DSLRs.
The comparatively low resolution of the LCD can be somewhat misleading in the field, making you think you've captured a great shot when you are in image playback, but when you zoom in with the e-dial, or put it on your computer, there is somewhat of a disparity between playback and what is actually captured. This was especially true with video capture, which I will discuss later on. With all things considered, it's an okay LCD monitor, and the viewfinder is accurate.
PERFORMANCE
Pentax has built a nice little camera with the K-x, though it does have a few flaws. It is poised to take over the place of the K2000, following the path they pursued with their point and shoots by including HD video capture in every camera. Some advanced functions position the K-x not quite at the entry-level, while at the same time it offers different scene modes and automatic settings, making the K-x on paper seem to be the best of both worlds. For the most part, the K-x is the best of both worlds, but some of what it lacks includes poor power performance, trouble focusing during live view capture, and a somewhat sluggish image buffer.
Shooting Performance
The K-x performed very solidly in our lab tests. We measured shutter lag (press-to-capture, pre-focused) at 0.03 seconds, which is just below the Olympus E-620. AF acquisition (using the viewfinder) came in at 0.25 seconds, while the K-x's continuous shooting reigns supreme at the top of the pile, at a fast 4.4 fps (slightly slower than the advertised 4.7 fps though).
Shutter Lag (press-to-capture, pre-focused)
| Camera | Time (seconds) |
| Olympus E-620 | 0.02 |
| Pentax K-x | 0.03 |
| Canon EOS Rebel T1i | 0.04 |
| Panasonic Lumix DMC-GH1 | 0.06 |
AF Acquisition (press-to-capture, no pre-focus)
| Camera | Time (seconds) |
| Canon EOS Rebel T1i | 0.19 |
| Pentax K-x | 0.25 |
| Olympus E-620 | 0.32 |
| Panasonic Lumix DMC-GH1 | 0.37 |
Continuous Shooting
| Camera | Frames | Framerate |
| Pentax K-x | 17 | 4.4 |
| Olympus E-620 | 6 | 4.1 |
| Canon EOS Rebel T1i | 170 | 3.8 |
| Panasonic Lumix DMC-GH1 | 5 | 2.8 |
There are three auto focus modes on board the K-x, including AF.S (Single mode) where focus is achieved via a halfway press of the shutter, AF.C (Continuous mode) where the subject is kept in focus after you press the shutter a half click and continues to keep the selected subject in focus, and AF.A (Auto) which switches between the two modes to give you the proper AF mode depending on the scenario. I mostly used AF.A, which worked great for single captures. However, when I used the continuous shooting drive, the AF.C was a requirement.
The AF uses a phase-detection system like most DSLRs, and offers four different options, including Auto 5 AF points, 11 AF points, Select, and Spot. All work well in the field, but the biggest issue we found with the focusing system was in Live View. It worked very hard to find its focus on objects, even in good lighting. Overall, the AF system works well, but does struggle a little bit in low light.
Continuous shooting is top notch. With a 4.4 fps rating, the K-x is completely capable of grabbing a split second frame in the middle of fast-moving action. Other exceptional areas of performance include the Shake Reduction feature, which reduces blur in images. When shooting, I tested out the SR with it on and then off, and it makes a dramatic difference.
Shake Reduction off
Shake Reduction On
Flash performance is spot on, giving a nice fill with its automatic modes and slow sync. The K-x is even equipped with a wireless flash mode that can set off optical slave flashes.
The biggest deficiency I found in the K-x is the powering system behind it. It uses four AA batteries instead of a rechargeable lithium-ion battery. We have mixed feelings about the AA system - it's convenient in that you can pick up batteries anywhere, but a DSLR takes a lot of juice to function. Even if you opt for rechargeable AAs, a power-hungry DSLR can run them down pretty quickly.
I advocate that AAs are better suited for point and shoots, but for a DSLR with advanced features, it is bound to be a power hog. In the case of the K-x, it's true. I went through four sets of batteries during the span of writing my review. The functions that chip away most at the power are use of live view, video capture, flash, and advanced camera processing like HDR and the different digital filters.
Lens Performance
Our K-x review unit arrived body-only, but I was provided with what the kit lens is for the camera - the smc Pentax DAL 18-55mm variable aperture lens. It's a pretty typical piece of kit glass, though it doesn't offer much reach for playing with depth of field. Although you can get a pretty shallow depth of field in Av mode, the lens does a reliable job of giving you what you need.
The camera's low-light performance is exceptional, so the glass if more forgivable when you can just bump up the ISO and still get a great low-light shot. This is great when you want an affordable lens like this one, and still want to get good dark shots.
Another great part of the camera body is that you can correct for aberrations that sometimes the lens can cause, and in this case, its inherently going to have some issues like barrel distortion and pin cushioning. Options include in-body distortion correction that works quite well, and also Chromatic Aberration control that helps get rid of purple fringing around the edges of high contrast. All in all, the K-x offers some nice alternatives in-camera to fixing problems in post-processing.
Distortion Correction Off
Distortion Correction On
Video Quality
There seems to be a problem with Pentax's rendition of HD video. Earlier this year I reviewed their ultrazoom X70 and the HD video was not good at all. We found all sorts of artifacts and grain in the capture. Video recording in the K-x improves on that, presumably thanks to a bigger image sensor. The video captures detail, but still struggles with the grain issue throughout the frame. The quality is pretty decent, but the noise levels make the video subpar compared to video capture from its competitors.
Image Quality
Image quality at default settings is very faithful to what the eye sees. There is also a cool manual tool for changing the image processing called Custom Image, which allows you to use sliders to change the saturation, hue, high/low key adjustment, contrast and sharpness of your image. Among these preset options with sliders are Bright, Natural, Portrait, Landscape, Vibrant, Muted, and Monochrome.
Other in-camera tools include Cross Processing and High Dynamic Range capture mode. The latter is available in HDR1 and HDR2, offering different levels of processing that create the effect of a wider dynamic range in your final image. What the HDR tool does is take three images simultaneously (one over, one under, and one correct exposure) and processes them together in-camera.
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The digital filters are also unique, giving you everything from a fish eye lens to a toy camera mode. It seems like more and more companies are putting in this camera processing modes to sidestep the digital darkroom edit.
 Extract Color |  High Contrast |
 Starburst |  Toy Camera |
Auto White Balance in the studio shot slightly warm, but in the field worked well under a variety of lighting conditions. Even on a blown out gray day, the AWB gave me the right exposure every time. Although the AWB works great in the field, you still have your pick of WB Daylight, Shade, Cloudy, Fluorescent Light Daylight Color, Tungsten Light, Flash, CTE, and Manual.
Auto White Balance, 3200k incandescent light
This brings us to the ISO performance charts, and this is where the Pentax K-x really sings. The ISO range is 200-6400, with expanded options up to 12800. As you can see in the lab samples, ISO 200 all the way to 1600 produce a great image, which is excellent for a 12.4 megapixel image. As I have said before, 12 megapixels is an optimal resolution for an APS-sized image sensor. I'm glad Pentax stepped away from pushing higher resolutions and concentrated on image quality instead.
 ISO 200 |  ISO 200, 100% crop |
 ISO 400 |  ISO 400, 100% crop |
 ISO 800 |  ISO 800, 100% crop |
 ISO 1600 |  ISO 1600, 100% crop |
 ISO 3200 |  ISO 3200, 100% crop |
 ISO 6400 |  ISO 6400, 100% crop |
Even at the 3200 and 6400 ISO settings, you get a workable and usable image, but this is where you start to also see the noise creeping into the cropped image. My field-testing matches right up with the lab test, giving me great images in low-light conditions, mainly due to the ISO performance.
Additional Sample Images
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 |  CONCLUSIONS The Pentax K-x is a worthy competitor for the major manufacturers out there, and is probably in line for the third best with the other smaller camera companies. Since the days of the K10D and the K100D, Pentax has made affordable DSLRs with great form factors, exceptional build quality and superb image quality. The K-x does not stray from that formula. The K-x is a great younger brother to their top-of-the-line K-7, though not without a few flaws. The LCD isn't great, focusing in live view is frustrating, battery power is drained quickly, HD video is somewhat noisy, and it can be slow to process images. But what it lacks in these areas it makes up for in price, image quality, construction, the perfect resolution, unique in-camera processing options, exceptional ISO performance and continuous shooting speed. The Pentax K-x offers a great value for its price. It gives you total control of image processing, manual shooting, a few post-processing shortcuts, and easy-to-use automatic and scene modes that makes it an entry-level to intermediate camera. Yes it has some quirks, it can be slow at times, and it drains battery juice at the drop of a hat, but we can't deny that the K-x is top notch otherwise. Pros:
Cons:
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