Pentax K-x Digital SLR Review

See the first full review of the K-x, the new DSLR from Pentax.

11/10/2009 - 14:19

Review by Matt Grayson

On the surface this looks like the Pentax K-m. But is it just that or a new model that looks suspiciously similar? That's what we plan to find out.

Pentax K-x: Specification
    Pentax K-x front view
    The new Pentax K-x builds on the K-m while not being as fast as the K-7.
  • Resolution: 12.4Mp
  • Sensor size:23.6x15.8mm
  • Sensor type: CMOS
  • Max. image size: 4288x2428
  • Aspect ratio: 3:2
  • Focus system: TTL phase difference detection
  • Focus points: 11
  • Focus types: AF/A (auto), AF/S (single), AF/C (continuous), Manual
  • Crop factor: 1.5x
  • Lens mount: Pentax K-AF2 bayonet
  • File type: RAW (PEF, DNG), JPEG
  • Sensitivity: ISO200-6400 (expandable to ISO100 & ISO12,800)
  • Metering system: TTL open aperture, 16 segment
  • Metering types: Multi, centre-weighted, spot
  • Exposure compensation: +/- 3EV in 1/3 or 1/2 step increments
  • Shutter speed: Bulb, 30sec - 1/6000sec
  • Frames per second: 4.7fps (max. (JPEG) 17 frames, (RAW) 5 frames)
  • Flash: Built-in, hotshoe
  • Flash metering: P-TTL, guide no. 12 (ISO100)
  • Flash sync speed: 1/180sec
  • Image stabilisation: Shake reduction (max. 4EV)
  • Integrated cleaning: Image sensor moving mechanism and SP (Super protect) coating
  • Live view: Yes, TTL by image sensor
  • HD Video: Yes
  • Video recording: 1280x720p/24fps
  • Viewfinder: Optical, fixed moulded penta-mirror type
  • Monitor: 2.7in TFT LCD (230,000dot)
  • Media type: SD, SDHC
  • Interface: USB/Video, USB 2.0
  • Power: 4x AA batteries
  • Size: 122.5x91.5x67.5mm
  • Weight: 515g (excl. battery and card)

Pentax Kx DSLR shutter button & command dial
Pentax Kx DSLR side
Pentax K-x: Features

It's been 9 months since the Pentax K-m was tested here at ePHOTOzine towers and I was really impressed with it. It was easy, fun and well built for a camera of that classification. So how does the new Pentax K-x measure up in terms of upgraded features?

Similar features include the chassis, metering and viewfinder. That's it. Pretty much everything else in the camera is new or upgraded, so this could be classed as a new camera over a replacement. With the new release comes a change in the stand point from the manufacturer. Indeed, with the recent release of the Canon Powershot G11 giving a lower resolution than the camera it replaced, it seems that the pixel race could well be over. In fact, Pentax have researched what consumers find the most important features in a camera. In 2007, the five most important things customers looked for were: resolution, price, image quality, functions and brand. Two years shows a distinct shift in what people are looking for with price being the main factor followed by resolution, anti-blur, brand and product size/weight.
Pentax Kx DSLR back view
Good news for Pentax with their down sizing technology as the new camera lacks certain features such as an articulating screen and a HDMI port to keep the size down. But if the research is accurate then why are manufacturers turning their attention to innovative features when functions aren't even in the top five? Why are we also seeing cameras coming out more expensive in this economic climate? Well the Pentax K-x is listed at £599.99 with the 18-55mm DAL lens or £749.99 if you get the new 55-300mm DAL in the twin lens kit.

My first impressions are that the K-x replaces the K-m, but certain factors seem to point to the camera being an addition to the range. Take the sensor, it's a 12.4Mp CMOS which sits in between the K-m at 10.2Mp and the K-7 at 14.6Mp. However, the new PRIME (Pentax Real Image Engine) II processor has been used in the new camera meaning the larger file sizes of the higher resolution can be downloaded quicker. On board 12bit A/D conversion has also been used for speedier transfers.

Expandable ISO is a feature being more commonly seen on DSLRs and Pentax have actually given us a reason why they've done it on the K-x. In a paper from Pentax Japan, they state that “ISO100 limits the dynamic range and therefore increases the likelihood of whitewash.” continuing with “Lower ISO equals lower gain which doesn't necessarily mean higher quality.”

Pentax Kx DSLR menu screen
The new, easier to use menu is accessed by pressing the info button.
As well as the core features having an overhaul, the menu screen has also been revamped. The main menu is the same which is actually not a bad idea as it means that current owners will be using a familiar UI. Pressing the Info button brings up a separate menu system which displays the fun, or some would say “interesting”, features of the camera. It comes up in a similar fashion to the current Olympus UI showing the options in rows. You navigate through the options using the navigation pad on the back.

One of the best features I think this camera has is the newly developed Cross Processing mode. It's an extension to the digital filters that were introduced on the K-m and expanded with the K-7. It gives the simulated effect that cross processing a film gives you and to add even more fun to the mode, there's a “random” option so the camera chooses what filters and patterns to apply to the image. It's certainly hit and miss but that's all part of the fun. It works by applying custom colours to the image and then adds a special pattern which Pentax are keeping close to their chests.

Pentax Kx DSLR HDR effect comparison
In camera HDR has been added which, like the K-7, takes three successive images and merges them together to get the best dynamic range possible. There's also CTE (Colour Temperature Enhancement) which works as a white balance override system. If you take a shot of a lot of grass, for example, and the camera starts to compensate because it thinks there's a cast, you can choose CTE in the white balance menu to correct the picture in playback or use live view to correct it before shooting.

On the subject of live view, it's a similar system to the previous models using multiple focus types including phase difference detection, contrast detection and face detection. HD Video recording is at 1280x720p running at 24fps. Not quite full HD but still HD nonetheless. Any video is recorded in Motion JPEG and the format is AVI.

Pentax K-x: Build and handling
It's an engineered plastic shell covering a K-m chassis. To keep size and weight down (and I think to not tread on the toes of the K-7), weather proofing and dust proofing hasn't been included in the build. That matches the K-m and I actually think it's a shame. Pentax could offer a full line up of cameras that have weather proofing and be one step ahead of their rivals.

Interestingly, the camera is 10g lighter than the K-m yet feels heavy in the hands. It's probably down to the AA batteries as they've been preferred over Lithium-Ion. Pentax say this is because the customer base looking at this model appreciate the availability and flexibility of AA over Li-Ion. It's true that they're more readily available and you can get regular Nickel Cadmium or decide to upgrade to Nickel Metal Hydride which are available as rechargeable. Lithium batteries are now available and as rechargeable and I think the only major concern with this battery format in these modern times is the weight of them. Strange then that Pentax, advocates of lightweight technology, should consider a heavier product.

The buttons are firm and responsive and the menu is easy enough to navigate. The addition of the new menu when pressing the info button is still an easy to use concept.

We've seen the Pansonic Lumix DMC-GH1 in it's dark red colour scheme and opinion over that is divided. Pentax have gone with a similar styling and made the K-x available in bright red, white, navy blue and black. Stephen Sanderson, Product Coordinator for Pentax UK said “Sales of the Pentax K-m in white were sold out in Japan before they'd even hit the shelves. They hope to copy that popularity with the different coloured versions of the K-x.” Releasing the camera in red, white and blue could be a nod towards the UK market, it could be blue, white and red to signify Pentax Europe's HQ move to Paris from Hamburg or it could just all be a happy coincidence. Either way, I reserve my opinion on the coloured cameras until I see them in the flesh.

Pentax K-x: Performance
Pentax Kx DSLR colour test chart
After talking quite positively about AA batteries for what could possibly be the first time in my life, I found the power consumption too much to handle. I used four new AA Lithium batteries and they were dead in 24hrs. I didn't use the camera excessively although I did use live view, so that could be the issue.

For clarification, the batteries were from an unopened packet so I knew they'd not been used previously. From my time in retail, I know that manufacturers can use half charged batteries to give away because they're cheaper but I'd still expect a lot more from this type. I didn't use live-view constantly, but possibly used it more than a photographer would because I was testing it.

It's unfortunate that this is the case with the K-x as the picture performance is very good. The colour chart is punchy in the primary colours and I like the balance of the earth brown and forest green. The skin tone pink could be stronger and there's a distinct lack of colour in the pastel tiles.

Portrait mode looks pretty good although I think it could be warmer. However, this could be down to the white balance interfering with the program as I selected a custom setting. There's plenty of detail in the hair and the exposure is pretty good. Adding flash has filled in the darker areas, added attractive catchlights and balanced out the tone.
Pentax Kx DSLR portrait
The normal portrait mode could be warmer.
Pentax Kx DSLR portrait with flash
Adding flash has filled in the shaded areas and added catchlights.

Pentax Kx DSLR toy camera mode
Toy Camera mode can make even the most tedious of subjects interesting.
Getting on to the fun stuff and the Pentax K-x has had the digital film effects from the K-m added to it. Therefore you can indulge in the cool options such as Toy Camera, Soft and Retro which can be individually tampered with to give an even wider amount of options for you.

The great thing about the Toy camera mode is that if you're using it and make a mistake, it usually doesn't matter because it gives the same effect as an older photograph from a time when technical accuracy of a picture of your house was less sought after. Think of pictures your parents or grandparents took and how badly composed they are, but still look good.

One of the standard scene modes found in the camera is the sunrise/sunset mode and I managed to use this really well when the morning light filtered through the leaves of a tree while I walked through a nature reserve. I took a shot without the mode on to see the differences and you can instantly see it's a lot warmer to accentuate the golden glow of the early sun.
Pentax Kx DSLR sunrise mode
An image of some leaves in the morning sun taken in sunrise mode.
Pentax Kx DSLR sunrise mode off
The same image with the mode turned off looks distinctly cooler.

Pentax Kx DSLR soft tone
Using the soft tone has amplified the softness of the morning sun.
Pentax Kx DSLR detail image
I also got a photograph of a huge wind turbine on the horizon one morning although in the photograph it's hardly noticeable. The morning mist was pretty strong so I put the camera in soft mode to bring out the softness of the mist. It also warmed the image so the morning sun came out a lot warmer.

The picture of the chain is from an unknown disused machine that has nearly rotted away it's so old. I like the level of detail from the chain. You can see the camera opted for a shallow f/3.5 aperture because of the lack of light. It was early morning and only a little filtered light was coming through.

While walking through the nature reserve, I spotted the moon still out, so used the cross processing mode to show what it will do to the different colours of green and blue and how it can affect exposure.

Pentax Kx DSLR Cross processing 1
The first shot using the cross processing mode.
Pentax Kx DSLR Cross processing 2
The second shot taken directly after the first.
Pentax Kx DSLR Cross processing 3
Green is the preferred colour but it's random.

Pentax K-x: Noise test
I was hoping for a good result in the noise test because so far I'm very impressed by how the camera works and the results it's given me.

ISO100 isn't a true setting for the reasons that are explained earlier but it's still a great result. The image is super smooth and this carries on throughout the entire set of photographs. In fact I'm overwhelmed with how good the noise test images are. Noise starts to distort the image at ISO6400 to a point that the detail of the petals is disappearing and small amounts of colour are invading the shadow areas of the grey card. ISO12800 is the same as ISO100 in that it's an equivalent and both have to be activated in the custom menu section. Even at this level, there's still some detail in the petals which is pretty astounding for a camera of this classification.
Pentax Kx DSLR ISO100 equivalent test
The ISO100 equivalent test.
Pentax Kx DSLR ISO200 test
The ISO200 test.
Pentax Kx DSLR ISO400 test
The ISO400 test.
Pentax Kx DSLR ISO800 test
The ISO800 test.
Pentax Kx DSLR ISO1600 test
The ISO1600 test.
Pentax Kx DSLR ISO3200 test
The ISO3200 test.
Pentax Kx DSLR ISO6400 test
The ISO6400 test.
Pentax Kx DSLR ISO12800 equivalent test
The ISO12800 equivalent test.

DxOMark provides objective, independent, RAW-based image quality performance data for lenses and digital cameras to help you select the best equipment to meet your photographic needs.

Visit the DxOMark website for tests performed on the Pentax K-x.

Pentax K-x: Verdict
Initial impressions of the new Pentax DSLR were impressive and I'm glad to say that they still are. It's unfortunate about the battery issue and judging by the comments at the bottom of this review, the K-m has suffered similar problems. Maybe it's time to start using Lithium Ion batteries in all DSLRs from now on because I'm unsure that AA types - even the lithium variety - have the capacity to cope with the new technology that uses so much power.

Still, using the camera was such fun with the HDR and Cross Processing modes, I never knew what I was going to get. Even simple photographs look great when they've been processed with a digital filter. I think if you have a few old Pentax lenses and you're looking to go to digital or feel that your work is stagnating and you need an injection of fun, you need this camera in your life.

Pentax K-x: Plus points
Cool built-in HDR and Cross Process features
CTE control for pin point white balance
Small body
Good price point
Excellent noise performance

Pentax K-x: Minus points
Weather sealing would be nice
Batteries need to be better





The Pentax K-x misses out on the rare ePHOTOzine Gold Award because of the batteries being used up so quickly.

The Pentax K-x costs around £600 with the 18-55mm f/3.5-5.6 and is available from Warehouse Express here:

Pentax K-x & 18-55mm DAL lens

Product Coordinator Stephen Sanderson spoke to ePHOTOzine about the Pentax K-x. See it now on Please note: This is not a final production video. This was shot when ePHOTOzine met with Pentax for an exclusive first look of the Pentax K-x. When we have the review product we will be producing a full, high quality video. We've put this up to give you a first look at the menu system and features.

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