An affordable high-resolution camera? Sounds good, but how does the K20D measure up against its rivals?...
So I got excited by the almost 15MP count of the new Pentax K20D, and yet cautiously expected the noise levels to be disappointing, with so many pixels crammed onto an APS-C sensor. For a struggling photographer without the £5,000 budget required for a Canon, an affordable high-resolution camera seems like a godsend. So is Pentax playing the generous God, or is it just a devilish ploy?
Features And Design
The K20D replaces the K10D of 2007. The new camera follows Pentax’s current business model by collaborating with Korean electronic giant Samsung – the electronics are produced by Samsung, while design and camera know-how comes from Pentax’s photographic expertise. Samsung, incidentally, has also produced an almost identical model, the GX20, which we’ll review separately in a forthcoming issue of WDC. At the K20D’s heart is Samsung’s newly developed CMOS sensor, with an effective resolution of 14.6 million pixels in APS-C format. This makes the K20D the highest-resolution enthusiast DSLR on the market, along with the Samsung GX-20, surpassing that of the recent models from Nikon, Canon and Sony. In fact the only current DSLR with a higher pixel count is Canon’s EOS 1DS Mk III, but that comes at the much higher price of around £5,000.
That resolution translates to images sized 4672×3120 pixels. In print terms this equates to approximately 15.6 x 10.4 inches at 300dpi. Be aware though that this produces large file sizes of approximately 45MB when opened and around 6MB for a closed JPEG, depending on the subject and amount of detail contained in the image. Files are saved with a choice of Raw options – either Pentax’s PEF (Pentax Electronic Format) format or Adobe’s universal DNG (Digital Negative) format – as well as JPEG. There’s also the obligatory Raw+JPEG option, still allowing the choice of PEF or DNG Raw formats. Incidentally, one of the few differences between this camera and the Samsung GX20 is that the Samsung only offers DNG as the Raw option.
Like its predecessor the K10D, the new camera has an optomagnetic 3D-Sensor image stabilisation system, which Pentax claims to have improved upon. This in-body system allows you to use standard Pentax K-mount lenses at slower shutter speeds, thus reducing the risk of camera shake. The company claims that shutter speeds up to four stops slower can be used with the newly improved system.
Furthermore the sensor’s sensitivity covers ISO 100-6400, allowing photography in a broad range of lighting conditions, especially useful for low light and without a tripod. In default mode, the ISO offers ISO 100-3200, with the ISO 6400 setting available in an extended mode. This top speed is set via bit-shifting (by using mathematical calculations) rather than the signal amplification of the standard ISO range.
A new Dynamic range function allowing +2EV extension for improving highlight and shadow details has been added, competing with the systems used by Nikon and Sony, for example. This is fast becoming a standard feature and is similar to using the Curves or Levels controls in Adobe Photoshop to extend the tonal range by retaining highlights, opening up the shadow detail and balancing the midtones. In contrasty lighting, such as when the sun is low or when the subject is backlit, the feature allows better retention of detail across the image.
The moving sensor cradle that corrects for camera shake also allows dust to be shaken from the sensor, by momentarily vibrating it at high speed. Any debris that is dislodged from the sensor is then caught on an adhesive pad in the base of the sensor chamber. This is backed up by an anti-static coating on the sensor’s low-pass filter to reduce the chance of dust adhering to the sensor in the first place. The LCD screen has been enlarged, now at 2.7 inches with a 230,000dot resolution, and incorporates live view so images can be composed via the screen. Being fixed, it lacks the multi-angle hinge found on models such as the Panasonic L-10 or Sony A350, which I prefer as this allows you to shoot from lower or higher angles such as at waist height or over crowds’ heads. A fixed LCD really requires the use of a tripod which is not always practical, and shooting handheld as you would with a compact camera is tricky and greatly increases the chances of camera shake.
On a more positive note though, the live view system also works with the Pentax Remote software, allowing images to be composed and taken via USB connection to a PC or Mac (again using a tripod or some sort of support). As an added bonus, this software is included with the camera, where other manufacturers can often charge extra for similar packages.
The body of the camera is extremely well made with a steel chassis and 72 weatherproof seals, yet remains small and light, weighing just 800g with its battery and SD card. As with all other Pentax DSLRs since the Pentax *ist, the K-mount is compatible with older Pentax lenses, as well as the new DA range, while an adaptor is available for using Pentax 645 and 67 series lenses. It is also compatible with the new range of Samsung’s K-mount Schneider lenses. However, there will be some loss of functionality on older lenses, such as no autofocus, or a lack of body-based aperture control, for example, so you should check with Pentax or consult the camera manual for more detail on specific lenses.
On the subject of autofocus, a welcome improvement is the new 11-point AF with nine cross-sensors. The previous model only had a central cross-sensor, so the new system will, theoretically, allow faster focusing across the frame on both horizontally and vertically placed focus lines. However, the camera fails to match the AF specification of rivals such as the Nikon D300 and Canon EOS 40D which have a greater number of focus points across the viewfinder frame.
The menu has also had a makeover, with a larger typeface and much clearer labelling of some of the functions. One of my criticisms of previous Pentax cameras has been their confusing, or downright annoying, esoteric naming conventions. The sensor-cleaning function for example, is no longer named ‘Switch dst msr pt’ but the much clearer, shorter and more obvious ‘Sensor Cleaning’ – I would have loved to have been at that design meeting!
Within the playback menu there are several direct image manipulation options including a High Dynamic Range (HDR) function. As far as I am aware this is the first camera to specifically include HDR in its functions, and so may prove popular with the growing subset of photographers who use the technique. It should be noted though, that this is a digital filter and doesn’t combine images like true HDR photography. Other unusual digital filters include a slimming filter to make fat Aunt Betty happy, colour extraction tools to leave a single colour in the image, while the rest convert to monochrome, and a soft focus tool to get rid of Aunt Betty’s wrinkles.
There’s also an illustration tool to convert images to line drawings, and the usual array of monochrome, sepia and colour filters.
The camera follows the K10D’s lead by providing incamera Raw processing, something now being mimicked by Nikon. Whenever any of these functions are performed, a new image file is created and saved, leaving the original file untouched. Of course, Raw files are automatically processed in the course of making a JPEG, but having the ability to edit on the go, and set your own parameters and so forth is quite useful, especially if you intend to upload to the web or make prints from the camera via PictBridge.
Among the last of the new features, and a very welcome one at that, is the X-sync or PC socket, allowing you to now sync the camera with an external flash or studio light set up. While this is always a good thing, the lack of a PC socket on recent cameras has seen a growth in hotshoe-based wireless flash sync accessories and it’s worth pointing out that this has become a better way to control off-camera flash. Not only does it allow better freedom of movement, but it completely removes the risk of high trigger voltage flash units frying your camera’s circuit boards. However, I’m still happy that the PC socket is included.
Thanks to the steel chassis and rubberised coating the camera is a very solid-feeling bit of kit. It’s still not a big camera compared to the Nikon D3, for example, but it looks and feels like a real camera. The design is traditional, aided by a left-hand mode dial where the old rewind lever would have been on a film SLR, while the grey LCD on the left maintains a link to cameras from the 1980s and onwards.
The placement of the button follows a similar pattern to that of the K10D, with easy access to the main functions, and a function button to quickly open the menu and change flash modes, WB and ISO. A rotating scroll wheel around the four-way controller is used to change the 11 AF point options, either auto, selective or centre. The four-way controller is used to select the AF point in Selective mode. In conjunction with the new standard 18-55mm f/3.5-5.6 kit lens, the AF speed and accuracy shows an improvement over the previous models.
A pair of front and rear command dials offer natural and quick exposure control of shutter and aperture, which I personally prefer to the single-wheel operation found on some other cameras. The dials are also used to scroll other settings such as exposure compensation, though most settings can be adjusted via the function menu or directly through external buttons. Overall, the controls are well laid out and don’t intimidate or confuse.
Like other cameras at this level, the K20D lacks scene or subject-based modes but does offer a decent range of picture options settings, which can also be customised in the menu.
It’s not a hard camera to use, and feels very comfortable with all of the main functions one would require of a semi-pro model. I thoroughly enjoyed using the camera and found it natural and instinctive to use.
Performance And Image Quality
The biggest enhancement over the previous model is the 11-point AF system, which is much faster and more accurate, though at times it does struggle to keep up in continuous shooting mode. The lenses are still the biggest hurdle to this, with Pentax consumer zooms tending to be slower and louder than those from other manufacturers. Unfortunately I didn’t have a chance to test the camera with the new DA* lenses with their faster and quieter SDM AF motor, but hopefully they will provide a better solution. The shutter is responsive and almost on a hair trigger, while the continuous drive of 3fps can hardly be said to be top of the class and it only offers 14 Raw or 38 JPEGs before using up the buffer. During the studio shoot I found it quite frustrating that the camera slowed down so much. This is one area where the camera fails to match the performance of the K10D, which allowed continuous JPEG recording to the card capacity. As the increased resolution results in larger file sizes, it would have been good of Pentax to also include a larger buffer to at least maintain the speed, if not improve upon the performance of the K10D. On the other hand the addition of a PC socket is much more useful, enabling me to use the camera with studio lights without messing around with hotshoe-based PC socket adaptors. I also shot handheld with daylight Kinoflow and HMI lights (daylight-balanced video lights) at relatively slow shutter speeds and, for the most part, achieved some decent and sharp results. However, I contest Pentax’s claims of four stops slower shutter speeds using the built-in sensor-based image-stabilisation system. Two stops would be a safer estimate.
Best results are obtained from Raw files and it is quite hard to distinguish between the DNG and PEF formats. The advantage of DNG is that the universal format is more likely to be future proof, so is better for archiving. JPEGs are pretty good though, especially if you are correcting the exposure issues in-camera, as the end file will not be as damaged by Photoshop.
I’ve often found Pentax cameras to underexpose slightly and this is certainly true of the K20D. While it could be said to be beneficial to err on this side, in order to prevent the highlights from blowing, the K20D takes matters a little too far. Images are around to 1 stop underexposed, giving them a dull look and either exposure compensation or correction in Photoshop is generally necessary.
The lack of noise at higher ISOs is pretty impressive, with better than expected results at ISO 3200, though images get a little too speckled at ISO 6400. They are still usable though, and Raw images should be easily fixed in Adobe Camera Raw or similar processing. At the lower end of the ISO range the results are pretty smooth, with no cause for concern and with noise only starting to make its first appearance at ISO 800.
Tone And Contrast:
The tonality of the images otherwise is pretty good though and final results are pleasing. Other features such as the dynamic range expansion proved useful, but less so than those of the Sony A700.
Colour And White Balance:
White balance is generally consistent and produces pleasing results even under mixed lighting. On occasion I needed to switch to a preset from Auto, but that’s usual. Colour overall is very good, with nice punchy images at the default settings.
Sharpness And Detail:
Image sharpness should be expected at this resolution and the Pentax certainly has plenty of potential. The K20D does produce sharp images, especially when viewed on A4 prints, or on screen. You need to be careful to keep the camera steady, however, as the closely packed pixel population will show up and amplify the effect of any movement. Similarly Pentax’s standard kit zoom lenses are lacking compared to those of some other manufacturers, so it’s worth investing in decent glass for really top-notch results.
Value For Money
The suggested price for the K20D is £899 for the body only, but it’s available for £100 cheaper in some retailers – often including the lens – and this makes it good value for money considering the spec and build quality. Along with the Samsung GX-20, it’s the highest-resolution model in its market sector and is made to a very high standard. Although we have often stated that resolution is not the be all and end all of a camera, it is still a factor in people’s buying habits and a reality of digital photography that more pixels and larger images are demanded by the consumer. In that sense, the K20D is a great proposition.
This is a solid camera with much to recommend it, not least its sensor and lovely handling. It stands its ground well against its rivals, even having an edge in terms of resolution. Despite some concerns about the exposure system, I managed to produce some great images and, more importantly, had fun doing it. This is really where the camera stands out; it?s great to use and feels comfortable and intuitive.
View sample shots of the Pentax K20D
View product shots of the Pentax K20D
11 point, 9 cross sensor
Adobe RGB, sRGB
Single, Continuous, Manual
Vertical Focal Plane
141.5 x 101 x 70mm
Pentaprism, interchangeable focus screen
Auto, Day, Shade, 3x Fluorescent, Tungsten, Flash
Single, Continuous 3fps, 14 Raw, 38 JPEG
TTL 16 segment, Evaluative, CW, Spot
Premium, best, better, good
PEF, DNG, JPEG, Raw+JPEG
2.7in TFT, 230k dots
4672 x 3104 pixels
15.07MP total/ 14.6MP eff CMOS, APS-C