Pentax K-5II: Performance

Performance

As the flagship of the small Pentax DSLR fleet, the K-5II commands a selling price hundreds or thousands of dollars less than the high-end offerings from Canon, Nikon and Sony. But does the relatively bargain price produce big-buck performance?

Shooting Performance
The K-5II starts up as you would expect any DSLR should, essentially instantly upon activation of the power switch. I was able to power up the camera, acquire focus and get off a first shot in about a second. Single shot to shot times are accomplished as quickly as you can reacquire focus and shoot a second time. Autofocus times are quite good in bright conditions and the camera features a focus assist lamp for dim light, however it seems to have a fairly limited range. But on the plus side, the AF system is advertised as having a brightness range of -3 to 18 EV, and the K-5II does very well in dim light. In a direct comparison with my Nikon D3S, my subjective impression is the Pentax AF system lags a tiny bit in speed, both in good conditions and dim light, but offers focus speed in keeping with its flagship role in the Pentax lineup. I have absolutely no complaints about focusing speed with the Pentax K-5II.

The continuous shooting rate in the K-5II is up to 7 fps with a buffer capacity for approximately 30 JPEG or 20 RAW images. In practice, the camera would manage 25 or 26 JPEGs and 22 or 23 RAW files before the buffer capacity slowed the shooting rate. Write time to completely clear those JPEGs using a 32GB, 600x Lexar SDHC memory card was about 15 seconds; clearing the RAWs required up to 28 seconds.

Like its stable mate, the K-30, the K-5II RAW/Fx button's default setting makes it possible to change individual JPEG images to a RAW file before the next image is captured. The camera must be set for single frame shooting (tripping the shutter with the self-timer or remote is OK); bring up the last image captured in playback mode and you'll see "AEL", "RAW" and a small rectangular icon all squeezed together in the upper right corner of the frame -- pushing the AE-L button on the camera back prompts you to save the file as RAW. If you power off the camera or take another shot before making the conversion on the individual image in question the opportunity to convert that file no longer exists. This setting can be disabled by the user and the RAW/Fx button may be customized to perform other functions.

Continuous autofocus tracking on moving subjects was pretty good, but on rare occasions while trying to hold focus on a small, moving subject at a distance the camera would lose focus lock. Any camera can lose lock if you don't keep the focus point on the moving subject, but with only 11 total focus points the K-5II has a little tougher job compared to some other manufacturer's systems using 39, 51 or even more focus points. Of course, my longest lens with the Pentax was the 18-135, shooting a bit over 200mm in 35mm equivalents - a longer telephoto would only make the focusing task easier on small, distant moving subjects.

The K-5II built-in flash has a guide number of approximately 42.5 feet at ISO 100 and as mentioned earlier, flash sync speed is 1/180^th of a second. Flash modes include redeye, slow sync, slow sync redeye, trailing curtain sync and wireless. I found the lens hood on the 18-55 and 18-135mm lenses would sometimes cast a shadow on close up images while using flash.

Battery life on the K-5II is reported by Pentax to be approximately 980 images without flash usage, or 740 images with 50% flash usage.

Lens Mount/Kit Lens
I reviewed the K-30 concurrent with the K-5II, and while both cameras are available as a body only they may also be had in kit form with either the DA 18-55mm F3.5-5.6 AL WR or DA 18-135mm F3.5-5.6 ED AL [IF] DC WR zoom lenses; I had an example of each lens available for these reviews. In addition, Pentax was gracious enough to also provide us with the FA 31mm F1.8 Limited and D FA MACRO 100mm F2.8 WR prime lenses. I'll review the performance characteristics of each lens as I observed them, and since both cameras use APS-C sensors this portion of the review will be the same for each camera.

The 18-55 mm zoom is assembled in Vietnam, appears to be well constructed and is weather resistant. Rotating the zoom ring approximately 90 degrees is required to go from one extreme focal length to the other and I found this action smooth and consistent. Manual focus from close focus to infinity requires about 100 degrees of rotation of the focus ring -- this action is light, and the front element of the lens does not rotate during focus. Minimum focus distance is 9.84 inches from the subject to the focal plane of the sensor (both camera bodies have focal plane marks on their exterior to help determine close focus distance). This lens displayed a slight amount of pincushion distortion at 55 mm and a slight amount of barrel distortion at 18 mm; zooming the lens to the vicinity of 26 to 28 mm eliminated the barrel distortion, with pincushion distortion starting to become apparent at about 35 mm. The 18-55 displayed good sharpness across the frame at 18mm; there was a slight amount of light falloff in the corners, as well is a slight amount of softness. At 55mm there was some softness in the corners but otherwise the lens looked uniformly sharp across the frame. There was a bit of longitudinal chromatic aberration (purple fringing) at both the wide and telephoto ends of this lens, but the effect was relatively benign and really required pixel peeping at 400x enlargement to become apparent -- 100x was not an issue for my eyes. Pentax has a lateral chromatic aberration adjustment feature in both the K-5II and K-30, but that defect (uncolored fringing around subjects with high contrast border areas) was not a major issue with this lens in the samples that I observed.

The 18-135mm zoom did not display an assembly point but also appeared well constructed and is weather resistant. Approximately 90 degrees of rotation of the zoom ring is required to go from one extreme focal length to the other, and this action, while a bit heavier than that of the 18-55mm was smooth and consistent. Manual focus required rotation of the focus ring through about 90 degrees of travel and the front element of the lens does not rotate during focus - minimum focus distance is 15.72 inches. This lens displayed a slight amount of barrel distortion at 18 mm and a slight amount of pincushion at 135 mm. Zooming the lens to around 22mm eliminated the barrel distortion but by about 28 mm pincushion distortion was beginning to become apparent. There was slight softness and light falloff in the corners at 18mm, and the vertical edges of the frame appeared slightly soft as well -- the horizontal edges appeared consistent with the rest of the frame. At 135mm the corners appeared a bit soft and the edges slightly soft. Longitudinal chromatic aberration (purple fringing) was present to a slightly greater degree at both ends of the zoom in this lens than that in the 18-55mm, but again this was during 400x pixel peeping.

The 31mm prime was made in Japan and seems robust and well-constructed thanks to its metal barrel, but unlike the other three lenses is not labeled as being weather resistant. Approximately 90 degree rotation of the focus ring is required for the full range of focus, and this action is light and consistent. Minimum focus distance is 12 inches. Distortion was not apparent in this lens, and sharpness appeared quite good across the frame. There were small areas of purple fringing observed in some high contrast boundary areas, but this required magnifications in the 400x range and was fairly benign even at that enlargement level. At 100x magnification images from this lens are quite nice -- it was my favorite walking around lens of the four I had at my disposal. Here are 4 shots with the 31mm:

The 100mm macro prime was assembled in Vietnam, is weather resistant and feels robust and well-constructed with a metal barrel like the 31mm. Rotation of the focus ring through approximately 270 degrees of travel is required for the full range of focus, and minimum focus distance is 11.88 inches; the lens features a 1:1 image magnification ratio (1X, life size). The focus ring displays focus distances throughout its range of travel and the lens barrel is imprinted with a handy depth of field indicator for f/16 and f/32 aperture settings. Distortion was not apparent in this lens and sharpness was very good and consistent across the frame. The 100mm macro threw me a curve when it came to chromatic aberration -- both of them. With lateral chromatic aberration adjustment disabled in the camera, images with high contrast boundary areas showed fairly distinct lateral chromatic aberration (colorless fringing) at 400x enlargements (but not really objectionable or noticeable at 100x). Enabling the lateral chromatic aberration adjustment really dampened down the colorless fringing, but seemed to produce a bit more longitudinal chromic aberration (purple fringing), which had been very slight with the adjustment disabled. Either way the 100 macro produced very fine images.

While macro suggests a lens used primarily for close-up work, there's no reason a macro can't be used for normal photography, assuming the focal length fits your needs. Here's a shot of the Queen of Hearts at Disneyland and then three shots moving into the real realm of macro.

While the four lenses provided by Pentax for this review all provided good to excellent distortion and chromatic aberration performance, both the K-30 and K-5II feature a lens correction feature accessible via internal menus. The cameras can correct for both distortion and lateral chromatic aberration, although these corrections can only be made when using DA, DA L, D FA or some FA lenses. Using the distortion correction setting may result in slower continuous shooting speeds. Here's a look at distortion correction at work on barrel distortion with the 18-135 mm lens.

18-135                                                                                       18-135 CORRECTED

Video Quality
Overall video performance is arguably the weakest facet of the K-5II's imaging repertoire, and while I'm personally not a big user of video in DSLRs, the difference between a good system and a so-so system is readily apparent. I have to say the K-5II features a so-so system: there's no continuous autofocus and for some reason Pentax has seen fit to make 720 HD the default setting. Upping the video ante to full HD is easily remedied via the movie menu, but the lack of continuous autofocus in the Pentax flagship seems a curious oversight. Clip lengths can be up to 25 minutes but vary given the resolution and image quality designated by the user. The camera displays the running time available for any particular clip on the monitor during capture, but full HD versions tended to fall around 5.5 minutes of recording time; 720HD at 30 fps was good for about 8.5 minutes and 720HD at 25 fps about 10.5 minutes.

The K-5II has a CMOS sensor, and can be susceptible to rolling shutter effect during exaggeratedly high speed panning while in video capture mode. Full HD video quality out of the K-5II is good but limited by the 25 fps only capture speed when it comes to fast action. Arguably, the K-5II's little brother K-30 has a more competent video suite than the top Pentax DSLR.

Image Quality
As disappointing as the K-5II's video performance was given the lack of continuous autofocus, still image quality is an entirely different matter. As you would expect from a DSLR, the K-5II produces very nice still images. Default color rendition in the camera's "natural" custom image style was quite accurate and pleasing.

Really close inspection disclosed the default sharpness settings to be a little soft for my taste. Sharpening settings in the K-5II are endemic to each of the custom image options, and are bifurcated. There are three fundamental levels of sharpening: "sharpness", "fine sharpness" and "extra sharpness." Within each of these levels are 9 degrees of sharpness, ranging from -4 to 4. Here's an example of the default setting (sharpness, 0) followed by the default setting at 4, fine sharpness 4 and finally, extra sharpness 4.

DEFAULT                                                                                    DEFAULT 4

FINE 4                                                                                        EXTRA 4

The custom image menu provides nine styles: bright, natural, portrait, landscape, vibrant, muted, bleach bypass, reversal film and black-and-white. In addition to sharpening settings for each of these individual styles, there are also adjustments for saturation, hue, high/low key adjustment and contrast. Here's a look at the natural, landscape, bleach bypass and black-and-white options.

NATURAL                                                                                   LANDSCAPE

BLEACH BYPASS                                                                         B&W

The K-5II offers an in-camera digital filter suite that includes toy camera, retro, high contrast, extract color, soft, starburst, fisheye, and custom filter effects. Within some of these individual effects you may have additional adjustments; for example the starburst option offers shape, effect intensity, size, and angle adjustments. An HDR capture feature takes three images with a single push of the shutter button and performs in-camera processing to produce a single HDR image; the user may choose from HDR auto or any of four levels of HDR intensity. HDR capture offers the user a quick and easy way to produce an HDR image, but bracketing an odd number of shots and processing them externally through dedicated HDR software offers the user a much wider range of adjustment than what's coming out of the camera.

I used auto white balance for all the images this review with the exception of the three macro shots of the watch, which were shot with the tungsten white balance preset. The K-5II does a pretty good job in auto white balance across a range of light, including incandescent (tungsten). In addition to auto the camera offers daylight, shade, cloudy, fluorescent (4 varieties), tungsten flash, CTE (color temperature enhancement), 3 custom settings that may be individually saved and a Kelvin color temperature scale ranging from 2500 to 10000 degrees and adjustable in 100 degree increments.

Multi-segmented metering is the default setting for the K-5II, which meters the scene in the viewfinder in 77 different zones. Multi-segmented is generally the best choice for a wide variety of lighting conditions but did, on occasion, clip some highlights in very high contrast scenes. Center weighted and spot metering options are available.

With the K-5II carrying an APS-C sensor with a 16.3 megapixel resolution - the same size and resolution as its stable mate, the K-30 -- the question becomes if the extra cost of K-5II gets you any more sensor performance over the K-30. The first clue might lie in the fact that the K-30's ISO range stops at 25600 while the K-5II continues on up to 51200.

ISO 100                                                                                     ISO 200

ISO 400                                                                                     ISO 800

ISO 1600                                                                                   ISO 3200

ISO 6400                                                                                   ISO 12800

ISO 25600                                                                                  ISO 51200

100 and 200 ISO in the K-5II are indistinguishable, and just as with the K-30, 400 is practically a match for the first two with just the tiniest bit of grain becoming apparent under very, very close scrutiny at 100%. 800 and 1600 each increase grain slightly, but both are still quite clean. It's at 1600 that the K-5II begins to show a slight advantage over the K-30, and the jump in noise from 1600 to 3200 in the K-5II is not so dramatic as in the K-30. The 3200 to 6400 ISO jump in the K-5II produces the singular most dramatic increase in noise thus far; in the K-30 a similar increase occurred at 1600/3200, so by the time we hit 6400 it looks like the K-5II is doing almost 1 EV better in noise performance than the K-30. 12800 and 25600 are both getting pretty grainy but still look a little better than the K-30 at the same sensitivities, and 51200 in the K-5II looks a bit grainier than 25600 in the K-30, but not dramatically so. If I were making large prints and had to, I could stretch shooting to 3200 the K-5II while 12800 and 25600 could be used for small prints or e-mail sharing if they were necessary to get the image. 51200 is the setting of last resort.

Additional Sample Images