Pentax K-5 II And K-5 II S Review: Pentax brings K-5 II in two versions

Pentax has renovated its top DSLR K-5 in 2012 and now offers it as the K-5 II and K-5 II s in two versions. The version with the small “s” in the type designation does without a low-pass filter, so that the 16-megapixel sensor should deliver even sharper and more detailed images. Both model variants benefit from a newly developed autofocus module that is designed to work much faster than the previously used one, especially in low light. K-5 II and K-5 IIs were launched in November 2012.

Brief assessment

Pros

• Fast autofocus that works even in very low light
• Over-complete equipment
• Up to ISO 800 excellent and up to ISO 1,600 very good image quality
• Bright 100-percent viewfinder with high-quality prism and interchangeable matt screens
• Robust, ergonomic, splash-proof housing

Cons

• Built-in microphone in mono only
• From ISO 6.400 on, the image quality decreases considerably
• Somewhat overloaded, confusing menu due to the many setting options

With the K-5 II Pentax wants to make a very good camera just a little bit better. This applies especially to the autofocus, which in the K-5 II should work faster and even in particularly dark environments. In addition, Pentax took the Nikon D800 and D800E as an example: To further increase the image quality in terms of resolution, Pentax offers a K-5 IIs, which, unlike the K-5 II, does not have a resolution-limiting low-pass filter.

This makes me to question of whether the autofocus has actually improved and how the Pentax K-5 II and K-5 IIs generally perform, and is the object of this short study right below.

In the K-5 II, a new autofocus module makes its debut with a measuring range of -3 EV to 18 EV. According to Pentax, the autofocus should work quickly and reliably even in low light and with high-intensity lenses. The AF is based on eleven measuring fields, nine of which are designed as cross sensors. There is little news to report about the display of the K-5 II: The control and playback monitor has a very fine resolution of 921,000 points, but is still neither foldable nor swivelable. Pentax, however, promises a viewing angle of 170 degrees. As a classic DSLR, the K-5 II also offers an optical viewfinder with 100 percent viewfinder field coverage, which can optionally be equipped with different matt screens.

Ergonomics and Workmanship

The K-5 II sits very securely in the hand due to the pronounced handle with a rubber application. There are also rubber applications on the back in the thumb cavity and on the left side of the case for a better grip. Numerous buttons, knobs and switches are scattered far and wide across the case, and some controls can be customized via the menu, such as the behavior of the two dials or the Raw button. In addition, the Pentax offers memory for individualised camera settings on the programme selector wheel, which is secured against accidental adjustment by a central button, so that you are well equipped for frequently used scene modes. The backlit LCD on the top of the camera, the rear screen and the viewfinder indicators provide information on the selected settings. Thanks to the high-quality pentaprism, the latter offers a bright, large image with 0.92x magnification that covers 100 percent of the image field.

In addition, the K-5 II has a Live View function on the rear screen. This measures three inches and has a resolution of 921,000 pixels. The display protection screen has been slightly anti-reflective and provided with a scratch protection by Pentax. It’s just a pity that the monitor is permanently installed, a folding screen would be great for unusual situations. The monitor image appears brilliant, rich in contrast and independent of the viewing angle; only in very bright environments do the shadows drown, as with other displays.

The contrast, brightness and color of the screen can be adjusted to the photographer’s wishes via a menu. The very extensive menu offers many setting options, but it also looks a bit confusing. However, most of the functions are self-explanatory. Pentax has even thought of the farsighted: the font of the current menu item can be enlarged to 150 percent. Furthermore, a quick menu allows access to numerous options to customize them with a few button presses and without scrolling in the menu. However, one must make the symbolism one’s own here, because not every symbol is to be understood in the same way, what one disguises with it.

Equipment

Just one look at the program dial makes it clear: the K-5 II was designed for ambitious photographers who know exactly how to control all the parameters to capture the subject perfectly. So you will look for scene mode programs in vain, but the camera still has an “easy mode”, i.e. an automatic mode that takes care of all settings itself. But Pentax does not stop at the standard programmes. The TAv mode, for example, allows manual control of aperture and shutter speed, while the ISO auto mode ensures correct exposure. The sensitivity range is from ISO 100 to 12,800, with an extension enabling ISO 80 and the range above ISO 12,800 up to ISO 51,200. The ISO automatic can be controlled extensively, upper and lower limits are freely selectable, including the extended range, and you can also choose when the automatic switches the ISO up. The exposure characteristics can also be adjusted, i.e. whether the camera gives priority to an open aperture with a short exposure time or a closed aperture with a higher depth of field. Alternatively, the camera prefers the optimum aperture with the highest resolution based on the data transmitted by the lens.

Various effects and settings allow the photographer great influence on the image results. An HDR function takes several differently exposed images and merges them into one image with high dynamic range. The strength of the effect and the exposure spread are adjustable. A multiple exposure function exists as well as an interval or bracketing function. This allows the photographer to take many pictures with a large spread at the push of a button and later create the HDR on the PC itself. Besides JPEG and the manufacturer-specific raw format PEF, the Adobe DNG format can also be set. The electronic spirit level is also smart. Not only does it indicate that the camera is tilted, but the Pentax can also rotate the sensor to automatically straighten the horizon. A slight camera tilt, as happens to almost every photographer, is compensated for without loss of image quality. The K-5 II makes use of the moveable mounted sensor, which of course continues to stabilize the image, so that you can enjoy the stabilizer with every attached lens, with manual lenses the focal length for the correct stabilization is selected in the menu – even with high light intensity.

Pentax has given the autofocus a boost as promised. Compared to the K-5 it works noticeably faster, especially in darker environments. Even if the view through the viewfinder no longer allows manual focusing due to the dark environment, the autofocus still does its job. All in all a significant advance over the K-5, with the K-5 II focusing and triggering in an average of 1/3 second. The speed of the focusing also no longer depends so much on the aperture of the lens, we measured no difference between F3.5 in wide angle and F5.6 in telephoto. Although the autofocus is so fast, it does not lose accuracy. Without focusing, the shutter release delay drops to a short 0.11 seconds. Nevertheless, you can also get the autofocus much slower by using the contrast measurement in the Live View. On the one hand, this shows a strong dependence on the aperture and on the other hand a generally slow focusing of 1.5 to 2.5 seconds. The shutter release delay contributes half a second – even though the mirror stays up, which makes the already quiet shutter release even quieter. At least there is no vibration due to mirror impact, which is also positively noticeable in series photography. Of course, the K-5 II also has a classic mirror pre-triggering.

The K-5 II also has a Full HD video function with 25 frames per second and MPEG-4 storage. The internal microphone provides mono sound only, but an external one allows stereo sound as well. In playback, the user has numerous functions at his disposal from raw development to filter effects.

Image quality

In principle, the K-5 II does not differ from the K-5 in terms of the sensor, as both rely on a 16 megapixel resolution, APS-C sized CMOS chip from Sony. So Pentax does without the leap into the 24 megapixel league, which competitor Nikon, for example, has already made in the entry-level class. Instead, the Japanese manufacturer relies on the proven, low-noise quality of the 16-megapixel controller, which we already praised in the K-5. Nevertheless, Pentax came up with something or rather used an idea that Nikon had already implemented in the D800 and D800E: a second variant of the K-5 II called K-5 IIs manages without an optical low pass filter, which should at least increase the resolution. Conversely, however, one must live with stronger moiré effects, which can appear on fine structures. Here, however, the photographer has possibilities to counteract the level of sharpness by clever choice, as there is less risk of moirés in blurred areas. We have examined both models with different lenses. On the K-5 II, these are the standard 18-55 WR zoom, which is sold as a set lens together with the camera, and the F1.4 fast premium portrait lens DA* 55mm. The latter served as a comparison lens on the K-5 IIs.

Especially at low sensitivities the K-5 II shows its strengths. At ISO 80 and 100 the signal-to-noise ratio is very good over 40 dB, up to ISO 1,600 it remains in the range of 40 to 35 dB or only minimally below. However, at even higher sensitivities, the image quality will visibly deteriorate. Brightness noise becomes visible from ISO 3,200 and increases at higher sensitivities. But the color noise is better under control by Pentax, here, the measuring curve even indicates a strong color noise filter from ISO 800 on, as up to ISO 400, a minimal colour noise is measurable, above that, it decreases and the measuring curve slightly goes up and down in jagged lines. The grain size remains at a low level despite increasing luminance noise, so that the noise grains do not take on too large, block-like dimensions. The possibility to reduce the JPEG compression to a minimum is certainly helpful here, which we have of course done for the laboratory test. But the strong noise reduction also makes fine details difficult. The finest details remain practically loss-free up to ISO 800. At ISO 1,600, the loss of detail is measurable to a small extent, but still within the green range. At ISO 3.200, the measured value is at the critical limit where the loss of detail can already be perceived. Above this sensitivity, this loss becomes increasingly evident. But one should not forget that the values above ISO 12.800 have to be enabled as an ISO extension first, quasi as a warning to the user that the image quality is not that good anymore. Before you can’t take a picture at all because of fading light, the photographer is able to do so.

Up to ISO 1,600, the input dynamics are at a very high level of around ten aperture stops, and even at ISO 3,200 they are still good. But above that it drops more and more clearly, so that you have to expect some restrictions depending on the scene mode. The Pentax transfers tonal values moderately divided, which means: for very crisp images, one has to give the tonal value curve a little more “boom”, but on the other hand, the JPEG-recordings are better suited for digital post-processing. Pentax also used a good sense of proportion when resharpening, because details are brought out, but the sharpness artefacts are not too strong at a maximum of ten percent. However, Pentax would be happy to improve the tonal range. Only up to ISO 200, many of the 256 brightness levels are used, up to ISO 3.200 it remains just acceptable with about half of the possible gradations, ISO 6.400 and more should not be used in the sense of fine brightness gradations. Things look much better with the fine colour gradations, which are still good even at ISO 6.400 and only limited above ISO 12.800.

Speaking of colors: The factory setting in which we test offers extremely vivid colours, which leads to strong deviations in colour reproduction. Fortunately, you can counteract this by choosing the appropriate settings and thus get a much more neutral and less screaming playback.

The 18-55 millimetre set-objetkiv on the K-5 II delivers quite a decent performance. On A4, the sharpness extends from the center to the edge of the image for an even image. The resolution measurement reveals edge blur with up to 40 percent loss of resolution in wide angle. Dimming helps to reduce this. With medium and long focal length the edge resolution is better. Overall, the resolution of just under 40 line pairs per millimetre (lp/mm) for a 16-megapixel camera is in the good range. The edge darkening is altogether low, but the distortion is barrel-shaped at 2.5 percent at wide angle, visible to the naked eye, neutral at medium focal length and slightly cushion-shaped at long focal lengths, but altogether low. Most disturbing are the chromatic aberrations, which are visible at least at maximum at any focal length and aperture. The wide angle is negatively noticeable here with even more distinct color defects at contrast edges.

The DA* 55 mm 1.4 SDM 55 mm 1.4 SDM is in a significantly higher performance class. With only minimal barrel distortion, perfect sharpness on A4 even at open aperture and minimal edge darkening, it is astonishing. However, it is not free of chromatic aberration; they occur in small form at open aperture and even increase slightly at high aperture. From F5.6, the limit of one pixel is exceeded on average. But the maximum deflections of the measurements do not deviate from the average as much as it is the case in 18-55, which means that the 55 offers uniformly small or large colour errors, depending on how one wants, also at the image edge. The most exciting thing, especially with such a fixed focal length, is the question of resolution. It may seem disappointing here that the maximum of just over 40 lp/mm is barely above the 18-55 zoom – and at open aperture it’s barely 30 lp/mm. But on the other hand, even at the maximum, the edge fall-off is well below the 20 percent mark, which means that the lens resolves very evenly, which it would not necessarily have to do as a portrait lens. The fixed focal length is especially suitable for low focal lengths, but also for other shooting ranges, for example to bring out details with the light telephoto for landscape photography. The highest resolution is achieved at aperture F5.6 to F8. Above this, diffraction then ensures a limitation of the resolution or a slow decrease. But even at F22, the resolution is above the 30 lp/mm mark, so you can close the aperture of the 16 megapixel camera a little further without having to fear pixel mud.

Even more goes on at K-5 IIs. Although the maximum of 4 lp/mm more may sound a little less, it is a good ten percent more resolution that it offers compared to the low pass filtered K-5 II. In principle, the other measured values do not differ greatly, but there are still significant differences. For example, the higher resolution with identical sharpness leads to higher sharpness artifacts. An equally logical consequence is the better performance of the K-5 IIs in measuring image detail across all ISO sensitivities. The fact that fine differences are important here is shown by the fact that the values are now in the very good range up to ISO 3,200, but this does not change anything about the steep drop in detail rendition at higher sensitivities. At ISO 6.400, however, the detail rate can still be passed off as good. Thus, those who think that they can handle the possibly stronger appearing moirés should confidently resort to the K-5 IIs, as the image quality is simply better without the low pass filter than with it. It’s nice that Pentax offers the user such an alternative in this price range around 1,200 Euros – but the K-5 II is almost 300 Euros cheaper.

Conclusion

The Pentax K-5 II is a rugged, super-equipped camera that doesn’t need to hide behind the APS-C competition. Its sealed magnesium housing is particularly compact and yet ergonomic. The absence of subject programs indicates it: This camera is not built for beginners. Apart from that you will find all possible and impossible settings and special functions like interval shooting or an HDR mode that can be adapted to the subject within wide limits. Compared to the K-5, the K-5 II stands out above all with its faster and more reliable autofocus, which can still cope well even in very dark environments where it is no longer possible to focus reliably through the viewfinder. The image quality is particularly impressive up to ISO 800 and is still very good even at ISO 1,600, but then drops rapidly. Pentax gets an amazingly high resolution out of the 16 megapixel sensor. If that’s not enough for you, you can go for the almost identical K-5 IIs, which has an additional resolution of almost ten percent. Only moiré-prone structures should be avoided because of the missing low-pass filter.

Pentax K-5 II Data sheet