Pentax K-5 Review

Ultimately, it is the image quality that makes a camera worth buying. For a digital SLR, image quality greatly depends on the lens used. While color, noise, contrast and exposure are properties of the camera, distortion, vignetting and chromatic aberrations are properties of the lens. Sharpness depends on the weakest link. So, the camera cannot capture more details than the lens lets through. Conversely, it is possible for a lens to transmit more details than the sensor can capture.

The Pentax K-5 offers a choice of multi-segment, center-weight and spot metering. It actually uses two distinct multi-segment metering systems, one dedicated sensor in the viewfinder chamber and the other using the image sensor. For most scenes which fall within the camera's exceptionally wide dynamic, exposure is great with both systems and coincides rather closely. When a scene has more dynamic-range than the K-5 can capture, the K-5's dedicated exposure meter prefers to over-exposuse, usually by ½ to 1 EV. Live-View metering on the other hand is more conservative. It also seems to consider more of the frame, making it more reliable for scenes with small but very bright spots such as lamps and lights. Center-weight and spot metering both work just as expected and behave the same when using the viewfinder or live-view.

The Pentax K-5 shows excellent hue accuracy. The default Bright color mode is very close to reality with just a slight amount of added saturation. The starting configuration for Bright is to use one step of extra contrast which gives very nice rendition of tonalities. Naturally, reducing contrast allows the camera to capture more dynamic range. Most color modes can be modified to provide accurate colors and tonalities, with independent control over the tone-curve of highlights, midtones and shadows. This lets more dynamic-range to be captured while maintaining contrast where it is desired. For a realistic but slightly softer look, the Natural color mode is also close to reality.

Sharpness is controlled in 9 steps along a standard, a fine scale or a extra fine scale. The lowest setting is quite soft on either scale while the highest setting is reasonably sharp. Even at the highest setting, the Pentax K-5 does not over-sharpen by much. Both fine scales produce images with virtually no artifacts but not as sharp as the standard Sharpness scale. The Extra Fine scale produces sharper images than the Fine scale with amazing preservation of fine-details.

Pentax has provided an excellent interface for setting image parameters. The most significant feature is a digital preview which is dynamically updated whenever an image parameter is changed. Another important detail is that the K-5 changes the color of any setting that is not at its default value to yellow. Settings at their default values are shown in green. The final touch is a 6-sided color space representation which shows how colors are affected by image parameters.

White-balance is rather complex with this digital SLR. Using custom white-balance, the K-5 achieves perfect color-balance. Preset white-balance either sets exact color temperatures or approximate ones, with the K-5 ultimately-deciding what color-balance to use. This is very accurate when it works but in extreme low-light the K-5 can get confused and produce way-off colors. The Automatic White-Balance setting works similarly with a custom setting to choose between subtle and strong correction. The strong correction produces very neutral results often but when it misses - usually in extremely low light - it leaves a strong bluish cast. On average, the K-5's automatic white-balance system seems to be a bit less reliable than other state-of-the-art DSLRs.

Noise levels are extremely low and a noticable improvement over previous generations. Up to ISO 400, images are perfectly smooth with virtually no noise to be seen. At ISO 800, a change in noise is barely perceptible. ISO 1600 shows a small amount of luminance noise but nothing that can be seen on anything but the largest prints possible. Another small jumps in noise occurs at ISO 3200, leaving it very usable for medium to large prints. This is where the Pentax K-5 does better than any cropped-sensor camera to date.

Even at ISO 6400, the K-5 produces images of impressive quality. Fine details get eaten away by noise at that sensitivity but medium-size prints still looks great with almost visible noise. ISO 12800 is more noisy with an easily noticeable loss of details. Reasonable 4x6" prints are still possible though. ISO 25600 can be used in case of emergency with small prints showing some softness but producing an otherwise recognizble subject. ISO 512000 is clearly one step too far, with a complete obliteration of details and high color noise, mostly in the green channel. A thumbnail is about the only thing that can look decent at this setting.

There are detailed controls over noise-reduction on this digital SLR. Noise reduction can be turned off or set to one of 3 levels. This can be done globally for all ISO sensitivities or specified individually. There is also a completely automatic option which strikes and excellent compromise between image noise and preservation of detailes. This is the default and it applies no noise-reduction until ISO 400, the weakest NR at 800 and a medium amount afterwards. This seems to be close to optimal although we did prefer lower noise-reduction to low at ISO 1600.

In operation, the Pentax K-5 is speedy and responsive. There are only a few moment where the photographer has to wait for the K-5. Startup, shutdown and shot-to-shot times are nearly instant. If instant review is enabled than it takes about 1 second for the image to appear. This is on the slow side for such an advanced model but it does not prevent the photographer from taking another shot before that. The buffer is deep enough to keep taking 20 shots in quick succession. When enabling lens correction, either Lateral Chromatic Aberration Supression of Distortion Correction, instead review is not instant at all, it takes roughly 5 seconds. The buffer depth gets reduced to less than 6 images in this case. When the buffer is full, one obviously has to wait for the camera. It is also worth noting that the buffer fills up faster at higher ISO, starting at ISO 6400 only 6 shots can be taken.

Image playback is also very fast.Entering and exiting playback mode is quick, as is scrolling normally between images. It takes just under 1 second to start zooming into an image. Panning and zooming is quite fast too. The K-5 allows to switch between images while zoomed-in. This is a handy function when checking a burst of shots to see which is the sharpest. In this case it takes about 1½s to load the next image. The camera is almost always shooting-priority, meaning that tapping the shutter-button returns it to picture-taking mode. Notable exceptions to this are when the camera performs a RAW conversion or HDR merge. Live-view performs very similarly in all respects except focusing.

Focusing is very fast and accurate, even improved over its predesesor. Under most conditions, the K-5 locks focus nearly instantly. Note that a slow lens can limit focusing speed.Continuous focus is fast but still not top-of-class. There are short but sometimes noticeable gaps where the camera has not kept a moving subject in focus.

The K-5 shoots continuously at 7 FPS or at 3.3 FPS. It does so very consistantly and quietly. Up to 40 JPEG images can be taken at 7 FPS. At 3.3 FPS, shooting can keep up until the memory card gets full. The RAW continuous-drive buffer limit is lower at 14. In order to reach those limits though, you need a fast enough memory card.

Although there is no formal procedure for measuring the performance of image stabilization, we can say that the Shake Reduction system in the K-5 appears to be normally effective to at least 2 stops, with 3 stop of effectiveness hit-or-miss. Battery-life is considerably improved, most likely due to a less power-hungry sensor. The K-5 can take 1100 shots with 50% flash use according to CIPA measurement standards.

The digital-level measures left-to-right tilt of the camera and shows it in 1 degree increments in the viewfinder and on the top status panel. This shows how tilted the picture is expected to be. If Horizon Correction is on, it does not show camera tilt less than one degree since it will be corrected. On the rear LCD, tilt is shown in 1/3 degree increments. When the tilt passes the point of correction, the indicator turns yellow. When the camera points upwards or downwards too much, the level can no longer records the tilt and displays 3 separate bars to indicate it is out-of-range. In practice, the digital level and horizon correction works rather well without being perfect when the vertical tilt is near the level's limit. Still, it greatly helps taking level photographs. The digital-level also measures front-to-back pitch which is optionally displayed on the rear LCD or over Live-View but cannot be corrected since the sensor would not stay parallel to the focus-plane.

There is in-camera HDR merging for cases when the dynamic-range of a scene is too high for the camera. It comes in 3 strengths or Auto. To do this, the camera takes 3 exposures in 3 EV increments and blends them. The result is a scene of high-contrast rendered as a low-contrast one. This gives best results for scenes which do not exceed by much the camera's dynamic-range, otherwise it tends to look very artificial. New to the K-5 is the added option to perform image aligment in camera. The necesarily reduces the field-of-view to accomodate for pixels which are not present in all images due to movement. It actually works quite well but prevents accurate framing through the viewfinder.

HDR Strong 1

HDR Strong 2

HDR Strong 3

The speedy 16 megapixels sensor of the K-5 lets it record full-resolution HD video with optional stereo sound when using an external microphone or mono sound using the built-in one. It shoots at a maximum of 1920x1080 @ 25 FPS. Lower resolutions of 1280x720 and 640x480 are possible at 30 FPS. Unlike the previous K-7, these are all standard resolutions and aspect ratios. At each resolution, there are 3 quality levels which vary compression used to produce M-JPEG AVI files. This codec is favored for editing video as it encodes each frame separately.

Movie-recording is almost fully automatic. Only aperture can be fixed before starting to record. Sound can be enabled or disabled, as can Shake Reduction. With video, shutter-speed is limited to the frame-rate of the movie, so ISO tends to vary quite a bit. This means that image quality can noticeably change when light levels are very low but given the K-5's stellar high-ISO performance, there is little to worry about. Not surprisingly, the highest quality 1080p video from the K-5 are simply superb with excellent quality and smooth motion. Since there is no autofocus of any kind during video, photographers will need a lot of practice to keep their subjects in focus while filming.

Videos from the K-5 appear very sharp with plenty of details, low noise and smooth motion. The advantage of a relatively large sensor gives optionally shallow-depth of field and the possibility of interchangeable lens gives a lot of flexibility. The downside is that a DSLR body and lens, designed with still images in mind, is harder to use as a video camera. The main issue is steadiness which is hard to achieve for more than a few seconds while holding the camera away from your body. Video cameras have electronic viewfinders (EVF) that keep the camera against you while shooting. This is not the case with a DSLR because video is implemented as part of live-view which shows on the rear LCD since there is no EVF on such cameras.

The Pentax K-5 shows exceptional image quality while improving upon the previously unmatched feature-set of its predecessor. Its wealth of features, many of them uncommon, helps users take better pictures. The combination of automatic horizon correction, 100% viewfinder and built-in stabilization gives relief to the photographer, letting him compose and frame with greater ease.

Image quality is unrivaled among cropped-sensor DSLRs with extremely low image noise, sharp details, plenty of dynamic range and natural image colors. Automatic white-balance could certainly be improved with custom white-balance and fine-tunable presets, it is not hard to get perfect results. The unique RAW data recovery feature presents an entirely different image workflow, where one can shoot JPEG and only when needed turn the last capture into a RAW file and reprocess it either in-camera or one the computer. Still, the K-5 has such sophisticated image parameters that one has a tremendous control over the look of captured images.

Speed and overall performance of the K-5 are solid. The most important factors of shutter-lag, focus-speed and shot-to-shot speeds are very quick and the camera remains very responsive under most conditions. The single-shot focus-speed is really good, locking focus nearly instantly under typical lighting. Continuous autofocus is good but certainly one of this camera's weaker points when comparing it to the class-leaders.

Ergonomics and controls are truly superb, particularly considering the relative compactness of the K-5. The Usability page of this detailed review covers all the details. The importance is that the K-5 gives efficient access to all important photographic controls and speeds up photography at the same time. The main feature disappointment is the Live-View system which falls short of previewing exposure and showing an accurate histogram.

The bottom line is that the Pentax K-5 is an excellent camera which has almost every feature available to a DSLR. It brings flexibility and superior image quality to a variety of subjects in a compact and well thought-out design. For low-light and action photographers, the K-5 is a worthy upgrade from its predecessor, mainly due to its fantastic control over image-noise. There are a few faster competitors though that one might consider if speed is a primary concern. As an all-rounder though, the K-5 covers more bases than any DSLR out there.