Pentax K-1 Review
General Image Quality
Before we dive in to high-ISO performance and other fancy features, let's take a look at the K-1's basic image characteristics and settings.
This image was shot with the SMC Pentax-FA 31mm F1.8 Limited, processed in Adobe Camera RAW and with an unsharp mask in Photoshop.
FA 31mm Limited, F11, ISO 200 (click image to enlarge) - original DNG file
The image reveals an impressive amount of detail and the colors perfectly reflect that the photo was taken close to sunset. The general image quality from the K-1 is stellar as also evidenced by this image, developed from RAW:
D FA 24-70mm @ 24mm, F8, ISO 200 - full resolution JPG file from RAW (cropped)
There is no shortage of detail and the color balance is as close to perfect as it gets.
In RAW mode, the Pentax K-1 has a tremendous amount of shadow and highlight recovery potential. Compare this out-of-camera JPEG file with what we obtained after developing the RAW:
To further analyze the K-1's shadow and highlight recovery potential, we photographed a daytime scene at ISO 100 while varying the exposure compensation from +5EV to -5EV at half-stop increments. Shadows and highlights were then recovered to the maximum extent possible during RAW development in Camera Raw.
Shadow recovery was possible even when the original image was severely underexposed. Even at -5EV, shadow noise remained minimal. Recovery of the sky color was possible up to +2EV, while most detailed remained intact up to 2.5EV of overexposure.
In practice, this means that you will have a tough time blowing highlights and problems with shadows, at least at base ISO, will be virtually nonexistent. It's worth nothing that the shadow/highlight alert that's available in camera operates on the JPEG file and thus does not imply that those areas cannot be recovered in RAW.
Noise levels following recovery of the -5EV image (100% crop)
We also attempted to quantify the overall dynamic range using a well-lit gradient scale. Though this test required a moderate amount of subjective interpretation, we found that effective shadow recovery on our test target could be carried out at as low as -8EV. The K-1's overall dynamic range lies somewhere between 14 and 15EV; we are confident that sensor test scores will confirm this and place the K-1 near the highest-ranked full-frame cameras currently available.
The K-1 produces images with a lot of detail. We look further at that two pages ahead in the section on Detail and Noise. We want to point out here, though, that the JPG engine in its default settings has an appetite for detail in that it simply removes fine detail by applying excessive sharpening, contrast or clipping as it evident from the images of the tree and the fishing boat:
The scene with the boat
Click on the below thumbnails to compare the full size crops. The cobweb which is clearly present in the RAW image has vanished in the JPEG:
|Developed from RAW||JPEG from camera|
The JPEG results out of camera when using the default "bright" image tone setting leave something to be desired when it comes to preserving detail. Previous Pentax DSLRs exhibited the same behavior, where snappy images take precedence over detail. By tweaking the custom image settings one may be able to achieve results with better detail and less contrast.
The exposure meter has an 86K pixel red-green-blue sensitive sensor with a very large sensitivity range; it goes from EV -3 to EV 18 at ISO 100. EV -3 corresponds to a shutter speed of 15 seconds at F1.4 and ISO 100, which is quite dark! We are more than satisfied with the metering range, and, to top it off, autofocus sensitivity also goes down to EV -3.
The light meter has the three usual metering patterns:
- Multi-segment where the exposure is set based on an analysis of the entire scene
- Center-weighted, where the exposure is based on the average light value of the scene with an emphasis on the center
- Spot, where the exposure is set based on the light value of the circle marked in the center of the viewfinder
We generally used multi-segment metering throughout and it works well. The other two patterns offer more control since there is less guesswork done by the camera. With K and M-series lenses and other manual lenses the pattern defaults to center weight and multi-segment metering is not selectable.
We found metering accurate with all the different autofocus lenses we used. The meter also did well at night, though there can be slight variability between live view and viewfinder metering.
Metering with lenses with an aperture ring but without an A setting (such as the Pentax K and M-series) is somewhat uneven as we have seen on previous models. Fortunately, the tendency is to underexpose which is easily corrected in post-processing. We've run through the apertures of an M 50mm F1.7 lens at ISO 100 using the standard procedure of stop-down metering with the green button (click an image to enlarge and browse):
|F1.7, 1/6000s ||F2, 1/4000s ||F2.8, 1/2000s|
|F4, 1/1000s||F5.6, 1/350s||F8, 1/250s|
|F11, 1/125s||F16, 1/90s||F22, 1/60s|
Refer to our manual lens metering guide for an overview of how manual lenses meter if you are new to Pentax. For lenses that do not need an adapter, the aperture stays wide-open and the camera only briefly stops the lens down to meter when the green button is pressed. M42 lenses will have a manual aperture diaphragm, on the other hand.
Users of lenses that cannot be metered wide open must be prepared to some exposure correction in post processing. Alternatively one could fine tune the exposure after the camera has metered the scene.
The K-1 has the same set of white balance settings as we have seen on previous models:
- Multi Auto
- Fluorescent (4 sub-settings)
- Color Temperature Enhancement
- Color Temperature (in Kelvin or Mired)
Hitting the INFO button brings up a customization screen where the white balance setting can be fine tuned along the green/magenta and blue/amber axes.
Testing this infinite set of white balance options is beyond the scope of this review, but we did a comparison of auto white balance with daylight (click to enlarge and browse):
|Auto white balance||Daylight|
We found auto white balance to work well as is also evident from the sample photos page. These presets will not affect most users, since the white balance can be retroactively selected for RAW files.
When shooting in the JPEG file format the processing of the image after exposure can be controlled by what Pentax call Custom Image. Custom image affects the image tone of the final image. Hitting the right button on the four way controller brings up the screen where one cane select how the future images should be processed. Any of these settings can retroactively be applied to RAW files either through the in-camera development menu or the Pentax DCU software.
|Select the custom image preset from this screen||INFO then brings up this screen for fine-tuning saturation, hue, high/low key, contrast and sharpness|
Each image tone setting can be customized with respect to saturation, hue, high/low key adjustment, contrast and sharpness (the latter has three modes which affects fine detail in different ways). If you are a JPG shooter we recommend that you through testing figure out which settings work for you. As mentioned above, the default settings with the Bright image tone has a tendency to remove detail.
The 12 image tone settings look like this, with all adjustments set to their defaults (click a thumbnail to enlarge and browse):
|Reversal film||Monochrome||Cross processing|
A new "auto" setting on the K-1 lets the camera decide which preset to use. We tried the Auto setting on the image of the house above and the camera wisely picked the "landscape" image tone. Even then we recommend that you select the image tone yourself so that you know what you get.
A notable addition to the K-1 is an expanded Clarity Enhancement setting (accessible via the main menu or Control Panel), which can boost or reduce mid-tone contrast through 8 different settings. This setting can be use to add pop to out-of-camera photos, though it is not as effective as proper desktop processing or RAW development.
Even in the "Portrait" preset, the camera's JPEG engine tends to exaggerate reds. Compare the JPEG result with the default output from Adobe Camera RAW:
However, the K-1 does include a new "Skin Tone" JPEG processing option which can be applied at the time of image capture (via the Control Panel or main menu), or while developing RAW files in-camera. This feature is currently not accessible through the Pentax software.
Click on any thumbnail below to compare the results (these are 100% crops taken with the FA* 85mm lens at F3.5). While we're at it, observe the tremendous amount of detail that the camera has captured!
With Skin Tone set to Type 1, the red cast is partially corrected. Type 2 incorporates the Type 1 adjustment as well as a blur filter to make the skin appear smoother. Since it does not work selectively, however, it blurs facial features, too.
Overall, this is a handy tool for quick out-of-camera portrait snaps.
The Shake Reduction system allows some freedom with respect of the positioning of the sensor. Users get control of this through the Composition Adjustment feature, which can be accessed via the main menu or Control Panel. In essence, Composition Adjustment turns any lens into a shift lens. The fact that this feature can be accessed via the Control Panel makes it much easier to use, but it's still a little bit quirky, as you have to switch in and out of live view every time you wish to make adjustments.
While you only get a few degrees of shift (along the x and y axis, plus roll), this feature can be useful in squeezing out hidden parts of the frame when using a wide-angle lens. Learn more about Composition Adjustment in our guide.
Like other Pentax DSLRs, the K-1 offers a suite of lens corrections that work in JPEG mode or when developing RAWs in-camera or using the Pentax Digital Camera Utility software.
There are four separate types of corrections: geometric distortion, vignetting, diffraction, and lateral chromatic aberration. Of these, distortion correction adds nearly a second of processing time following image capture, so we recommend that you use it sparingly during high-speed shooting. The remaining corrections have a negligible impact on performance.
The various lens corrections are quite effective, but they only work with select Pentax lenses, including all digital-era lenses (DA, DA*, D FA, D FA*) and more recent film-era lenses (FA Limited, FA*, some FA primes). They are convenient for snapshots and quick JPEG previews, but not of much use to RAW shooters.
Shake reduction (SR) also plays a role for image quality since it allows for using slower shutter speeds without sacrificing resolution. The in-body SR system in the K-1 goes back many generations of Pentax cameras and has been refined further for the K-1 as covered earlier. It is reliable and it works well. Pentax promises that you can use shutter speeds five steps slower than the standard hand-holdable speed and still get sharp images. This is even slower than with the previous models. The camera industry has a standard test that measures the benefit in number of shutter speed steps. This means that the specified five stop improvement is based on a measurement and is not just a claim invented by the marketing department. The effectiveness of shake reduction is something that is very hard to test and verify for us since in actual use it depends on how steady a hand the photographer has at that given moment.
We were able to get great results while hand-holding with the D FA 24-70mm and FA* 85mm at shutter speeds as slow as 1/4s.
We are happy to see than Pentax was able to retain (and even improve) in-body image stabilization with the large sensor assembly in the K-1 in particular since this technology makes it possible to provide these other features:
- Pixel shift resolution (increased effective resolution and cleaner colors)
- AA filter simulator (the presence of an anti-alias filter can be simulated by sensor vibrations)
- Astrotracer (the sensor can follow the movement of stars by moving the sensor)
- Composition adjustment (can correct converging lines e.g. when photographing architecture)
- Horizon correction (corrects minor tilting of the camera by keeping the lower sensor edge level with the horizon)
The Pentax K-1 supports a number of in-camera HDR capture modes. HDR capture can be enabled using the function dial, Control Panel, or main menu.
There are five different HDR modes, including HDR1, HDR2, HDR3, HDR Auto, and Advanced HDR. Each HDR capture consists of 3 separate exposures, and the bracket value for these can be configured in the camera's menu.
In RAW, all the camera's HDR modes embed the 3 exposures in a single DNG or PEF file. These can then be processed using the supplied Pentax software or select third-party programs, though we aren't aware of a method to split the exposures.
While the numbered HDR settings just vary the strength of the HDR effect, Advanced HDR is something entirely different. In the latter mode, the camera greatly boosts shadows and mid-tone contrast as illustrated above. Note that this is purely a JPEG effect, and that RAW files give the end user control over the appearance of the result. Thus, the K-1's HDR mode are mainly a more convenient way of enabling bracketing.
We don't hesitate to deem the image quality from the K-1 to be simply excellent. The level of detail, the dynamic range, and the color rendition in RAW mode are all stellar. This is hardly surprisingly given the reputation of the K-1's 36-megapixel sensor, which is based on the Sony sensor originally used in the Nikon D800.
For JPEG shooters a wide range of customization is possible regarding white balance and image tone, including contrast, saturation, and sharpening. With sufficient patience, it's possible to configure JPEGs to deliver the look that you desire. To get the most out of the camera we do recommend shooting RAW, however. The JPEG engine tends to boost contrast and saturation at the expense of dynamic range, and fine details are often over-sharpened and made ugly. Overall, the K-1 packs a surprisingly large number of snapshot-friendly features, including automatic JPEG profile selection, filters, and HDR effects.
We are pleased to see that the camera can correct for various optical flaws for all current Pentax lenses and select legacy lenses. Crop lenses also have correction profiles for crop mode.
Metering is accurate with modern and A-type lenses, and auto white balance works really well as we've observed with other models fitted with the newer RBG sensor. Metering with manual lenses outside of live view can be hit-or-miss as matrix metering is not supported with those, however.