Pentax K-m DSLR Review

Matt Grayson tests the K-m from Pentax. The newest entry class DSLR to hit the streets.

Posted: 15/12/2008 - 14:18

With other manufacturers concentrating on the high end DSLRs lately, the lower end has been pretty much left alone and unchallenged - Enter the K-m.

Pentax K-m: Specification

Resolution: 10.2Mp
Sensor size: 23.5x15.7mm
Sensor type: CCD
Image size: 3872x2592
Aspect ratio: 3:2
Focus system: TTL-phase-matching SAFOX VIII
Focus points: 5 point wide AF
Lens mount: Pentax KAF2 bayonet
File type: JPEG, RAW (PEF/DNG)
Sensitivity: ISO100-3200
Storage: SD, SDHC
Focus types: Auto, single, continuous, manual
Metering system: TTL open aperture 16 segment
Metering types: Multi, centre-weighted, spot
Exposure compensation: /- 2EV in 1/3 or /-3EV in 1/2 step increments
Shutter speed: 30sec-1/4000sec & bulb
Frames per second: 3.5fps max
Flash: Built in, hotshoe
Flash metering: P-TTL
Flash sync speed: 1/180sec
Image stabilisation: Pentax Shake Reduction
Integrated cleaning: Yes
Live view: No
Viewfinder: Optical fixed moulded penta-mirror type
Monitor: 2.7in TFT LCD
Interface: USB 2.0
Power: 4x AA batteries
Size: 122.5x91.5x67.5mm
Weight: 625g (inc. 4x alkaline batteries and memory card)

At £339, the Pentax K-m offers a new UI layout, easier to use systems, downsizing technology for a smaller body and the same dust alert system from the K200D/K20D. Comparably, the older Nikon D60 at £315 comes with a similar focal length 18-55mm lens which has in-built image stabilisation (Vibration Reduction), 10.2Mp, EXPEED processor, slower 3fps and lower 3 point AF system.

Alternatively, the Canon EOS 1000D and 18-55mm IS (image stabilisation) lens at £317 has 10Mp, 3fps, 7 point AF system and DiG!C III processor.

The Olympus E-420 at £299 with a 14-42mm lens offers the same resolution on a 4/3 sensor, easy to use UI, 2.7in screen, 3.5fps, live view and 3 point AF.

Pentax K-m Features

With each DSLR released, Pentax have tried to push boundaries in one way or another such as large resolution on the K20D and dust alert on the K200D. The K-m has all the features of the now middle of the range model but it's in a much smaller housing. Despite this shrinkage in dimensions thanks to Pentax' downsizing technology, the sensor is still the same size and resolution as the K200D and matches the dimensions of the Canon EOS 1000D while being slightly bigger than the Nikon D60.

A look around the body shows a different layout in the buttons from the other Pentax models with the removal of the image stabiliser switch, function button and all important RAW button. The screen is the same size as the K200D but looks bigger on the smaller body.

A useful addition to the body comes in the form of a help button. Located on the right shoulder next to the exposure compensation button, its task is to give clearer instructions on the feature you're using.

The command dial has all the features of the K200D minus the bulb setting for ultra long exposures which means the K-m has a maximum shutter speed of 30sec until it goes in Manual where bulb is accessible. It still offers the usual PASM modes as well as the Sv mode for sensitivity-priority. In this mode, you can adjust the ISO using the E-dial (thumb wheel) while the camera controls the shutter speed and aperture.

With the cr eation of the K-m, Pentax wanted to bring a simplified camera to the class so that users upgrading from compacts or new to photography could get to grips with the system faster and easier. A new user interface has been installed and bears a similar resemblance to the Olympus DSLRs. It replaces the function button and is easier to see as it's now on the monitor. All you have to do to enable the menu system is press the OK button and it'll pop into life highlighting green whichever option you're on.

The AE lock button on the top right of the camera has been replaced with an AF button and this can push the focusing without pressing the shutter release. It's useful for if you have a problem half-pressing the release to focus.

Internally, the same sensor has been used from the K200D which means it's slightly larger than the Nikon D60 but the same size as the Canon EOS 1000D. This will be beneficial over the Nikon for noise, but it's a well known fact that the Nikon EXPEED processor handles issues such as noise much better than the previous Nikon sensor. The noise test images will prove whether the Pentax PRIME processor is a worthy competitor.

Dust reduction and dust alert have been left in which is a relief as it's one of the few things that benefit Pentax products over the others. If this is your first read of a Pentax DSLR, dust alert is a scanning device that analyses the sensor and finds any dust. It then shows you an illustration on the screen of it's location and you can decide whether you need to shake the sensor to remove it. These results are saved onto your memory card in a folder called Dust for if you wish to save them.

Pixel mapping is also available and this procedure checks every pixel on the sensor to see if they're still operational. It doesn't have to be performed often, in fact once a year is suitable.

A feature that Pentax are very proud of is the newly upgraded auto program system that analyses what's in the frame and selects the appropriate scene mode to get the best result. This technology is newly developed and has been seen on a few compact cameras recently, such as Panasonic's intelligent auto and Nikon's BSS (best shot selector) systems.

A digital camera wouldn't be a digital camera these days if it didn't have some sort of dynamic range compensation. This feature has a different name dependant on the company you look at such as Sony's dynamic range optimiser and Nikon's D-Lighting which do the same job by increasing detail in shadow areas and clipping highlights to make sure they're not blown out.

One of the more interesting features on the K-m is the photo effects. These aren't new in terms of finding them on cameras, but the actual effects that are available are. The K-m offers modes such as Toy Camera, Retro, Soft, Starburst and black & white. Probably the most fun out of all of them is the Toy Camera which isn't at all as the name suggests. In fact it's more like a pinhole effect with vignetting, blur and colour bias. The great thing is that those three levels are adjustable to give more or less vignette and blur or leaning the bias of the colour to red, blue or green.

All the other effects have adjustable levels and you can also take a test shot while in the menu by pressing the exposure compensation button. It then allows you to see the changes, make amendments and retake it before shooting the final shot.

On top of these effects, scene modes are available by selecting SCN on the thumb wheel or you can also choose picture styles in the menu. These are preset modes such as landscape or portrait mode but have variable levels such as sharpness, hue, saturation and contrast.

As a DSLR, the K-m has the ability to record in RAW which, if you don't know, is an untouched file type. It records exactly what's in front of it with no tampering from the processor in any way. Unlike JPEG, this means the image will have no boost in colours and no compression thereby losing no detail. This is great because the detail in the image is much higher than JPEG but on the downside, it's a larger file which takes longer to download.

This is the difference between a 4Gb card holding 921 JPEG images and 236 RAW images. Continuous shooting is also affected and at high speed, you can take five frames in JPEG or four in RAW. At low speed, you can take as many JPEGs as you want until the memory card is full but only seven RAW files.

The downside is the removal of the RAW button on the side of the camera that you can find on the K200D and K20D. It's a really useful button for quick conversion and it's a shame it's not available on the K-m. You can set the camera up to shoot both RAW and JPEG if you need to but that needs to be done in the menu system.

Pentax K-m Build and handling

Build quality of the K-m is surprisingly good. I only say surprisingly because it's a low classification camera and they aren't usually the models to have money splashed on them. Saying that, it's not a magnesium alloy body, it's stainless steel and a new chassis was developed for the K-m using downsizing technology that Pentax are famous for.

Thanks to the new interface, the camera is extremely easy to use which is great news for newcomers. Coupled with the help button and simplified layout, this could well be the easiest DSLR to use on the surface.

Of course, all cameras have minus points and with the ease of use, it's the core menu that let's it down. Pressing the menu button takes you to the core system which is laid out in a similar fashion to the more advanced K20D with custom functions and more indepth changes available. The help button doesn't work here either, so it's worth keeping hold of the manual until you're sure what to do.

Initial reports speculated that the flash would have a guide number of 13 keeping it at the same specification of the K200D, but this has been lowered to 11 which is a little bit low. A hotshoe is available for external flash if you do need more power, so all is not entirely lost.

Pentax K-m Performance

The Pentax Real Image Engine (PRIME) processor must work overtime on the JPEG files if the primary colours are anything to go by. Blue, red, yellow and green are all boosted with rich earth brown and green and a balanced skin tone. In fact, I'm really impressed with the colour test chart image and my only gripe would be to pump the colour up on the pastels down the side of brown, orange and blue so they don't look so sedate.

Looking at the landscape image and again I'm amazed at the amount of colour being recorded. It's saturated but not excessively and I think that Pentax have got it right on the nose. I used the 50mm f/1.4 lens and there's no fringing which means the microlenses aren't throwing any distortion up. Detail is good in the grass and trees to the right.

To see the amount of detail the K-m can record in JPEG and RAW, I shot a macro image of the peacock feathers using the 100mm f/2.8 macro lens. The JPEG can be downloaded here and hasn't been compressed by save to web so may take longer to download than the others. The RAW image is available to download here: Pentax K-m RAW macro image.

Pentax K-m Sample Photos

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As well as the Toy Camera mode that has been highlighted previously, the K-m also records in Soft mode. You can also make modifications to the image while you watch and take test shots before shooting. I took an image of a church doorway then tried variations in different white balance settings. Fluorescent had a warming effect while tungsten cooled it down to a spookier look.

Portrait mode gives a balance, even exposure and it's possible to see that the camera has selected the correct setting because the face is pin sharp while the neck is out of focus. Plenty of detail is evident in the hair and the eyes are sharp despite my worries about the focusing system.

Using flash has pretty much ruined a decent shot. The image is the wrong cast white the cream background looking purple and the skin looking overly warm. It reminds me of a holiday photograph taken on a disposable camera which is something that I don't expect from a DSLR.

Pentax K-m Focusing and metering

With a 5 point AF system, the K-m sits in the middle of the main competitors mentioned above as the Canon benefits from 7 points while the Nikon and Olympus have only three. One thing that I find annoying is the lack of a focus confirmation on the screen. When focus is locked, the familiar double beep sounds and a small green hexagon lights in the information bar at the bottom of the viewfinder, but nothing lights up on the screen. The problem with this is that if you're focusing on the eyes in a portrait, there's no way of knowing that it's where the camera has focused on the area that you want it to. That is unless you select the centre focus point in the menu but that messes up focusing with portraits or any other off-centre subject.

Metering is through-the-lens (TTL) and you get to choose from the 16 segment multi metering where the camera splits the frame into sections, meters from each one, analyses the results and selects the best exposure to suit each readout.

Centre-weighted is pretty self explanatory. It meters from around 85% of the frame in an oval shape which fades out to the edges. This means more bias (weight) is given to the centre of the image. It can sometimes get fooled by bright areas such as windows and doors if you're inside or lights at night. Spot metering takes a reading from the exact centre of the frame and only pays attention to a small spot around 2-3% of the frame. It ignores everything else so some interesting results can be gleaned.

Metering can be tied to focusing by choosing the option in the custom menu. This means that whatever the camera focuses on it will also meter from, which is good for portraits.

Pentax K-m Noise test

I'm surprised that the K-m only has a maximum sensitivity of ISO3200. Although detail is starting to die out at this stage, with some noise reduction software, I think an extra setting of ISO6400 could be possible. ISO100-400 are great with smooth tiles of white, grey and black along with plenty of detail in the petals.

There's no jump in quality from any setting, the whole thing is gradual which makes me think there's no noise reduction taking place. If that's the case then the sensor is doing a great job.

Pentax K-m ISO test images

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Pentax K-m Verdict

It's great to see Pentax fighting the corner of the user on a budget while other companies concentrate on higher spec models. For the money you will spend, the build quality is great, the colours are rich and the effects are enough fun to keep you occupied for a while.

The noise performance is good although I feel it's been capped too low, the new UI works well and although it's a little on the heavy side, it feels great in the hands.

I'd love to see a top end DSLR from Pentax now, just to complete the stable. Maybe a full frame model would be good but until then, newcomers to DSLRs have another option to look at and it's a really good one.