Overall handling and operation
In terms of handling and operation, our comments on the K-5 match almost exactly those which we made about the K-7. Despite its relatively small dimensions the K-5 handles well and always feels stable in your hands - the excellent build quality gives it a reassuringly solid feel and the well-designed and sized grip makes for comfortable operation, even for photographers with larger hands. There are plenty of dedicated 'top level' and 'second tier' controls, and they all fall easily to place. We are equivocal about the locking exposure mode dial, but got used to it fairly quickly.
What we like most about how the K-5 handles is the fact that it is one of the few DSLRs at this level which offers fluid ergonomics when the camera is held to the eye, as well as at arms length. Specifically, the K-5's ISO and exposure compensation controls are very well-placed for quick adjustment, and changing AF points is quick and easy too, simply by jogging left/right/up/down on the rear controller. Other key shooting controls are arranged sensibly close at hand, either on the cardinal points of the 4-way controller itself, or a quick jump away, through the 'info' screen.
As a result of the camera's comprehensive feature set, the menu system is naturally somewhat complex, but all the options are grouped and sorted in a reasonably intuitive way and after a few days of shooting you'll easily find your way through the menu system and around the camera in general.
Moving on to video, and since the K-7 was reviewed, our expectations of video shooting modes in DSLRs have been raised, both in terms of functionality and ergonomics. Whist the K-5 offers an a decent video shooting mode, we're disappointed by the lack of a direct video shooting button (see 'specific handling issues', below).
Specific handling issues
The lack of a dedicated movie shooting button was excuseable in the K-7, but our expectations of video implementation are much higher now than they were even in the relatively recent past. The K-5 boasts an impressive video specification, and it is a shame that by relegating it to the exposure mode dial, Pentax has put video capture at one remove from the conventional photographic experience. Unlocking the mode dial and moving it to the video position is easy enough, but it makes the K-5 less spontaneous as a video camera than we'd like it to be. Ideally, we want to be able to customize the green button on the rear of the K-5 to fulfil this requirement.
We'd describe the K-5's menus as a midpoint between the Canon EOS and Sony Alpha approaches - the menu options are colorful and reasonably logically organized (with the exception of button/dial customization, which for some reason is found in the REC menu), but actually manipulating the various options is not always as intuitive as we'd like.
The issue is one of consistency. Sometimes, to adjust a certain option you simply click right, set the relevant option in a drop-down menu, then click left to cancel the dropdown. Sometimes, however, (when adjusting 'movie' or 'live view' settings for example), clicking right sends you to a new menu screen, and after making the necessary changes you need to press 'menu' to return to where you were.
The K-5's overall performance is very impressive. As we'd expect for a modern DSLR, shutter lag is so minimal as to be irrelevant (which is why we no longer include this test in our reviews) and in use, we never felt that the camera was keeping us waiting. With image auto review set, it takes approximately one second for a maximum quality JPEG to appear on the rear LCD screen after it is captured, and only slightly longer (1.4 seconds approx) for a RAW+JPEG frame. Pulling a captured image up on the rear LCD using the image review button is virtually instantaneous, and we have no complaints about the speed of zooming or panning captured images either. Accessing and exiting the K-5's menu system is equally slick, which makes the experience of using the camera almost completely stress-free.
The only major barrier to fast and efficient operation is one which has already been mentioned - the relegation of movie shooting to the exposure mode dial. We prefer the dedicated movie buttons which have started to appear on SLRs such as the Canon EOS 7D and Nikon D7000.
Performance doesn't simply mean speed of course, it also means how well the camera's key systems do their jobs. We'll cover continuous shooting and AF further down this page, but as for the other systems - metering and white balance - both are very capable. The K-5's AWB system is impressively reliable in mixed artificial lighting, and in every environment in which we used it - from bright daylight to low, fluorescent light in a museum, it gave good, acceptably neutral results. The only time that manual intervention was necessary during our testing was when shooting in a museum lit with a mixture of natural and artificial light. Depending on the composition of the scene, the K-5's AWB system occasionally gave an unexpectedly magenta cast, but a little experimentation with the WB presets was all that was required to give more neutral results.
On to metering, and like white balance, the K-5's metering system is hard to fault in normal use. Shooting some of the same scenes that we tackled with the Nikon D7000, we encountered none of the same overexposure problems in bright light. If anything, the K-5 has a slight tendency to underexposure, but only in dull, overcast conditions. In good light, the K-5's metering is all but infallible, and although its effects are often very subtle, the 3-level 'Shadow Correction' is handy for giving shadow areas a slight lift in exceptionally contrasty scenes. It is worth noting at this point that because the K-5's sensor has such a low noise floor, shadow detail is much easier to enhance than with most DSLRs. Speaking of enhancements, Highlight Correction is another useful dynamic range option, which successfully gives an extra stop (approx) of highlight detail without any noticeable penalty in increased mid tone/shadow noise.
The Pentax K-5's automatic ISO functionality is amongst the most sophisticated available. In its default mode, it aims to deliver a shutter speed adequate to prevent camera shake using the '1/equivalent focal length' rule of thumb - so a minimum of 1/40sec at 18mm, 1/200sec at 135mm, and so on. But there are two other options, labelled 'Fast' and 'Slow'. The K-5's instruction manual is remarkably opaque about what these actually do, saying they increase the sensitivity 'actively' and 'as little as possible' respectively, but dig a little deeper and you find there's a little more to it than that.
Set to 'fast' the K-5's automatic ISO control aims to deliver shutter speeds significantly higher than are required simply for avoiding camera shake, so a minimum of 1/80sec at 18mm, and 1/400sec at 135mm. Set the control to 'slow' and at any given focal length the K-5 delivers a shutter speed which is adequate for preventing camera shake with image stabilization turned on - a minimum of 1/25sec at 18mm, 1/125sec at 135mm, and so on. So if you're shooting sports and don't care too much about high ISO noise, you can set it to 'fast' to freeze motion blur more effectively. For landscapes, architecture, portraits, etc., set it to 'slow' and you should benefit from better image quality as the camera will choose lower ISOs. This is a useful feature, and it is a shame that it is so poorly documented.
Continuous Shooting and Buffering
The following timings were originally made with firmware version 1.0 - we have since re-tested the K-5's continuous shooting performance with firmware 1.0.1, and updated timings follow below.
The Pentax K5 offers pretty impressive continuous shooting performance - a maximum frame rate of 7fps (although we have found that it wavers slightly, between 6.3-7fps) for 20-30 JPEG images (depending on JPEG quality settings) images. This compares very favorably both to the Canon EOS60D and the Nikon D7000, but isn't quite as good as the Nikon D300S or Canon EOS 7D, which both have significantly bigger buffers in JPEG mode. In RAW mode, the K-5 (with updated firmware) gives very good performance, and manages 24 images in a high-speed burst (increased from 8, with original firmware).
The following figures are the result of our own timings - all operations are performed and timed three times, with the average given.
- JPEG (4 star - highest quality): 6.3 - 7fps for 25 frames, then 1.5 - 2.5fps in short bursts. Approx 15 seconds to recover.
- JPEG (3 star - standard quality): 6.3 - 7fps for 30 frames, then 1.5 - 2.5fps in short bursts. Approx 10 seconds to recover.
- RAW (DNG): 6.3 - 7 fps for 24 frames, then 1.2fps. Approx 18 seconds to recover.
- RAW+ JPEG (standard): 6.3 - 7 fps for 24 frames, then around 0.7 fps. Approx 18 seconds to recover.
All tests conducted at 1/250 sec in AF-S mode with a 16GB Lexar Professional 133x Class 10 SDHC card.
Autofocus speed / accuracy
The K-5's AF system is new, and Pentax's claims that it is faster and more accurate than the system used in the K-7 are bourne out in our shooting. It has the same SAFOX IX+ designation that is carried in the medium format Pentax 645D, - the 'x' denoting that the AF sensor is sensitive to light color, as well as intensity.
Whilst we do not have a specific testing regimen for AF, we have used the K-5 extensively, and we have found that its AF system is extremely capable, in both bright and very low ambient lighting conditions. In the dull interiors of bars and museums, the K-5 doesn't give 100% accuracy, but out of the hundreds of frames which we shot, only a handful are marred by focus errors. Autofocus acquisition is extremely fast and positive, with both conventional screw-driven AF lenses and SDM (ultrasonic-type) optics.