Pentax K-1 Exposure

Saturation & Hue Accuracy
Vibrant colors with default Bright Color Tone setting, with average hue accuracy.

Saturation. The Pentax K-1's default image tone setting of "Bright" pushes most colors by quite a bit at base ISO, especially blues, dark greens, dark reds and purples. Mean saturation at ISO 100 is 116.9% or 16.9% oversaturated. That's about 7% higher than most other brands at default settings. Overall, colors are very bright and punchy, a trait we've come to expect from Pentax. Mean saturation gradually declines as sensitivity increases, to 109.8% at ISO 102,400, but it makes a more sudden drop at maximum ISO, to 101.6% . You can of course always select a different image tone preset and/or turn down saturation and contrast settings to suit your own tastes. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. Caucasian skin tones from the Pentax K-1 were pleasing using Manual white balance in our test shots, however Auto white balance produced an overly pinkish appearance. Good results here. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.

Hue. The Pentax K-1's mean "delta-C" color error of 5.62 after correction for saturation at ISO 100 is about average for a DSLR these days. Most noticeable were moderate shifts in orange toward yellow and cyan toward blue, with smaller shifts in some reds, yellows, and greens. (The cyan to blue shift is very common among the digital cameras we test; we think it's a deliberate choice by camera engineers to produce better-looking sky colors.) Color error remains fairly stable as ISO climbs up to 25,600, but increases at the highest ISOs, however that's to be expected . Hue is "what color" the color is.

Note: Most of our K-1 lab shots were taken with Natural color tone instead of the default Bright setting (our standard is to use the default), however our Far-field (white building) shots used Bright, and we've retaken our Still Life ISO series using the default Bright color tone as well. (Our previous single-shot Still Life ISO series now has a -NAT filename suffix and our PSR Still Life series is still Natural since we've already written up an in-depth analysis comparing them.)

Exposure and White Balance

Indoors, incandescent lighting
Very warm results with Auto white balance, but good color with Incandescent and Manual white balance settings. Average exposure compensation required.

The Pentax K-1's Auto white balance setting had a difficult time with the household incandescent bulbs used in this shot, producing a very warm image with a strong orange tint when using the default "Strong" Correction option; a "Subtle" Correction setting is also available, which would produce even warmer results. Results with the Incandescent setting are actually pretty good, though, just slightly on the warm side. The Manual setting produced very accurate color balance, perhaps just a touch cool. Note that a Kelvin setting is available, as well as Color Temperature Enhancement (CTE) white balance option which exaggerates the temperature of ambient light. The Pentax K-1 required +0.3 EV exposure compensation for a good exposure, which is about average for this shot. Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.

Outdoors, daylight
Bright colors with high contrast; very good exposure accuracy.

The Pentax K-1 produced very good overall exposures without the need for exposure compensation for both our "Sunlit Portrait" and Far-field shots, producing a good balance between highlights and shadows. This is much better than average in terms of exposure accuracy, however default contrast is quite high, leading to significant highlight clipping in both shots. We preferred Manual white balance for the Portrait shot as Auto white balance produced overly pinkish skin tones, however Daylight white balance also performed well. Color in the Far-field shot is quite pleasing, if a bit pumped.

See full set of test images with explanations
See thumbnails of all test and gallery images

Native Resolution
~3,350 lines of strong detail from JPEGs, a little higher from ACR converted RAW files.

Our laboratory resolution chart reveals fairly distinct line patterns up to about 3,350 lines per picture height in the horizontal direction, and to about 3,350 lpph in the vertical direction in a best quality JPEG before lines begin to merge, though individual lines are somewhat faint and some aliasing can be seen as early as 2,200 lpph. Complete extinction of the pattern didn't occur before the 4,000 line limits of our chart in both directions. An Adobe Camera Raw conversion yielded slightly higher numbers, with individual lines that were more crisp and distinct. The ACR processed RAW image does however show a lot more color moiré, as they often do. (Note that AA Simulation was set to its default of off, for maximum resolution.) Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.

Pixel Shift Resolution Mode
~3,450 lines of strong detail from JPEGs, about the same from converted RAW files.

The Pentax K-1's Pixel Shift Resolution mode yielded slightly higher resolution from in-camera JPEGs at about 3,450 lines both horizontally and vertically but with much crisper lines, however there were still aliasing artifacts in the form of luminance moiré patterns starting as early as 2,300 lines. Adobe Camera Raw wasn't really able to produce higher results, and interestingly, it still contained more false colors near the limits of resolution than the in-camera JPEG.

Click here for much more on the Pentax K-1's Pixel Shift Resolution mode.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Fairly sharp images with very good detail, though with visible edge-enhancement along high-contrast edges. Minor noise suppression visible at base ISO.

Sharpness. The Pentax K-1 produced fairly sharp images with very good detail at default settings. Edge enhancement artifacts are visible on high-contrast subjects such as the sharpening halos around the lettering and border in our Mas Portell bottle label above left, though we've seen far worse. Overall crispness is not bad, but JPEG images can look a touch soft at default settings. Edge enhancement creates the illusion of sharpness by enhancing color and tonal differences right at the edge of a rapid transition in color or tone.

Detail. The crop above right shows only minor detail loss due to noise suppression. Individual strands are still distinguishable even in the lighter shadows, though they begin to merge as shadows deepen, and in places where the tone and color of adjacent strands is very close. Still, very good performance here, with remarkably low chroma noise.

Some individual strands of hair do show aliasing artifacts in the form of "jaggies", however the K-1's selectable AA filter should help prevent those from occurring when enabled (AA Filter Simulation was disabled by default here). Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.

Anti-aliasing Filter Simulator
During the exposure, the Pentax K-1's anti-shake actuator can oscillate the sensor assembly microscopically in either a linear (Type 1) or circular (Type 2) motion, simulating the effects of an anti-aliasing (or optical low-pass) filter. To see the effect on image sharpness and aliasing artifacts, roll over the links in the table below to compare settings:

As you can see above, AA Filter Simulation Type 1 blurs fine detail slightly, while Type 2 offers a slightly stronger effect, which should go a long way to reduce aliasing artifacts and moiré as can be seen in the center of the starburst crop. The crop on the right is a real-world example that usually shows stronger moiré in the blinds, but it's still a useful comparison to see the slight reduction in aliasing and sharpness. Note that the AA Filter Simulator is not available in burst mode or during Bulb or HDR capture, and the full effect cannot be achieved at shutter speeds faster than 1/1000s. Pentax has however provided a very useful AA filter bracketing mode, which will take 3 shots with the different AA filter settings in case you're not sure which setting to use, or want to selectively merge different exposures to reduce aliasing in specific areas.

RAW vs In-Camera JPEGs
As noted above, the Pentax K-1 does a pretty good job at capturing lots of fine detail in its JPEGs, but more detail can often be obtained from carefully processing RAW files, while at the same time reducing sharpening artifacts. Take a look below, to see what we mean:

In the table above, we compare an in-camera JPEG taken at base ISO using default noise reduction and sharpening (on the left) to the matching RAW file converted with Adobe Camera Raw 9.1 using default noise reduction with some moderate but tight unsharp masking applied in Photoshop (150%, radius of 0.3 pixels, and a threshold of 0).

As is usually the case, Adobe Camera Raw delivers finer detail than the camera's processing, and its default noise reduction does a little better with our difficult red-leaf swatch, resolving a little more of the fine thread pattern, however it did produce more noticeable moiré patterns. ACR also did a better job with color, rendering the pink fabric closer to reality instead of the more magenta interpretation from the camera. Adobe Camera Raw also produced finer detail in the mosaic, but left behind a bit more noise, as seen in flatter areas. Overall, though, the Pentax K-1 does a good job with its JPEGs, but as is usually the case you can extract slightly more detail (with more accurate color and fewer sharpening artifacts) with a good RAW converter.

ISO & Noise Performance
Very good high ISO performance.

The Pentax K-1's images are very clean and detailed from ISO 100 through 400 and are practically indistinguishable except in the red channel where there is a bit of softening at ISO 400. ISO 800 shows a touch more luminance noise, but fine detail is still excellent. Detail is still very good at ISO 1600, with a tight film-like noise "grain", low chroma noise, and very little fine detail lost to noise reduction (except in reds). At ISO 3200, there's increased blurring and more visible noise "grain" particularly in the shadows, but fine detail is still quite good, and chroma noise continues to be very well-controlled. ISO 6400 shows noticeably stronger luma noise but it's still fine-grained, leaving quite a bit of fine detail left. Chroma noise is still quite low, but it starts to show in the shadows. Image quality takes a larger step down at ISO 12,800, with fine detail becoming noticeably softer because of the higher noise, and chroma noise becoming visible in darker midtones. Image Quality at ISO 25,600 and above falls off quickly, though, with much stronger luminance noise, noise reduction artifacts, as well as increasing chroma noise which becomes very obtrusive at ISOs 102,400 and 204,800.

Overall, though, high ISO noise performance is very good for a high-res full-frame camera, though perhaps not quite as good as some competing models in JPEGs. High ISO noise in RAW files however appears to be very competitive with similar models, and even slightly better than its closest rival, the Nikon D810.

Of course, the impact of noise and detail loss are highly dependent on the size the photos are printed at, and pixel-peeping on-screen has surprisingly little relationship to how the images look when printed: See the Print Quality section below for recommended maximum print sizes at each ISO.

Extremes: Sunlit, dynamic range, and low light tests
High default contrast results in mediocre dynamic range in JPEGs. Excellent low-light performance, capable of capturing bright images in near darkness.

Sunlight:
The Pentax K-1 struggled with harsh lighting in the above test. Default contrast is quite high, and as a result, quite a few highlights were blown in the mannequin's white shirt and in some of the flowers, even at default (0 EV) exposure. Shadow detail is however very good, with low noise levels even in the deepest shadows. Note that these shots were captured with the Pentax K-1's D-Range control set to "Off."

As expected, we were easily able to recover virtually all blown highlights from the matching DNG file, indicating the dynamic range available in K-1 RAW files is quite good and perhaps even class-leading.

Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here. In actual shooting conditions, be sure to use fill flash in situations like the one shown here; it's better to shoot in open shade whenever possible.)

D-Range Settings
The Pentax K-1 offers four Shadow Correction levels (Auto, Low, Medium and High, plus Off) as well as two Highlight Correction levels (Auto and On, plus Off). As the name implies, Shadow Correction works to raise shadow levels while attempting to keep highlights and midtones as they are, and inversely, Highlight Correction attempts to reduce highlights without darkening shadows and midtones. Both can be used simultaneously.

Mouse over the links to see how the various settings for D-Range affects our high-contrast Far-field shot, and click on a link to get to the full-res image. (The effect can be a little subtle in shots like those above, so we used a mouse-over to better show how each setting compares.)

Shadow Correction. Above, we can see a progressive lightening of shadows and midtones as the Shadow Correction setting is increased, while highlights are pretty much untouched. And in this case, the Auto setting produced results very similar to the manual Low setting. If you look closely at the shadow detail, you will notice an increase in noise as the setting is turned higher, but that's to be expected and noise levels are still quite low from the K-1.

Highlight Correction. Highlight Correction also worked as expected, with On and Auto producing virtually identical results here (compare Highlight On or Highlight Auto to D-Range Off), toning down highlights to preserve them while keeping shadows and midtones roughly the same. Note that Highlight Correction is not available at ISOs below 200, so these were shot at ISO 200.

HDR Capture
The Pentax K-1 has a High Dynamic Range (HDR) capture mode where the camera takes three images (underexposed, normal, and overexposed) in quick succession and combines them in-camera into one image. If performed properly, this method should result in much higher dynamic range, without the additional noise penalty that comes with boosting sensitivity or lightening shadows. (In fact, it can reduce shadow noise by combining shadows from the overexposed shot.)

There are five HDR settings available: Auto, Advanced (which applies Clarity Enhancement as well), and HDR 1/2/3 providing three blend settings. Each setting has three possible exposure ranges (±1 EV, ±2 EV (default), and ±3 EV). There's also an optional Auto Align feature for use when shooting without a tripod, which is enabled by default on the K-1.

Mouse-over the links above to compare thumbnails, and click on them to access full-resolution versions.

The Auto setting worked reasonably well on our Far-field test shot, reducing highlights and bringing out shadow detail while maintaining a natural, non-HDR look. HDR 1 mode produced a relatively realistic image though with an obvious HDR-ish look, HDR 2 produced a stronger effect, and HDR 3 resulted in a very unnatural, almost cartoonish image with strong haloing. We didn't test Advanced.

As with most HDR systems there can be slight focal-length crop with Auto Align active as you can see with the HDR 3 and HDR Auto images, and watch out for ghosting that can occur when images contain movement between exposures, such as the moving leaves in some of the above shots.

Dynamic Range Analysis (RAW mode)
While we once performed our own dynamic range measurements based on in-camera JPEGs as well as converted RAW images (when the camera was supported by Adobe Camera Raw), we've switched to using DxO Labs' results from their DxOMark website. As technology advanced, the dynamic range of modern high-end cameras in some cases exceeded the range of the Stouffer T4110 density scale that we used for our own measurements. DxO's approach based on RAW data before demosaicing is also more revealing, because it measures the fundamental dynamic range of the sensor, irrespective of whatever processing is applied to JPEGs, or to RAW data by off-the-shelf conversion software.

In the following, we use DxO's "Print" dynamic range results, which are scaled based on camera resolution. As the name suggests, this scaling corresponds to the situation in which you print at a given size, regardless of how many megapixels the camera might have. (In other words, if you've decided to make a 13x19 inch print, that's the size you're printing, whether the camera's resolution is 16 or 300 megapixels.) For the technically-minded, you can find a discussion of the reasoning behind this here on the DxOMark website. Also note that DxO Labs uses a signal-to-noise (SNR) threshold of 1 when defining the lower boundary of acceptable luminance noise in their dynamic range measurements, which corresponds to the "Low Quality" threshold of the Imatest software we used to use for this measurement.

Here, we compare the Pentax K-1 (in orange) to a couple of high-resolution full-frame cameras, the 36-megapixel Nikon D810 (yellow) and the 42-megapixel Sony A7R II (red). You can always compare to other cameras on DxOMark.com.

As you can see from the above graph (click for a larger image), the Pentax K-1 actually has slightly higher dynamic range at its ISO 100 setting (14.6 EV) than the Nikon D810 (14.36 EV) at its ISO 100 setting, however at the D810's lower base ISO of 64, dynamic range is a touch higher at 14.76 EV. That's a very minor difference that will most certainly not be visible in real-world images, though, and the K-1 has a slight advantage over the D810 up to about ISO 12,800, where results from the two cameras merge.

Compared to the Sony A7R II, the Pentax K-1 enjoys a 0.7 EV advantage in dynamic range at base ISO, but between ISO 400 and 800, the Sony catches up and overtakes the K-1 at higher ISOs, with up to about a one stop advantage at between ISO 51,200 and 102,400.

Bottom line: Excellent dynamic range results from the Pentax K-1, particularly at lower ISOs. Click here to visit the DxOMark page for the Pentax K-1 for more of their test results and additional comparisons.

Low Light. The Pentax K-1 performed very well in terms of image quality in our low-light tests, capturing clean, well-exposed images at the lowest light level (1/16 foot-candle) with the lowest sensitivity setting (ISO 100). As you'd expect, noise is higher at ISO 3200, but it appears well-controlled and very fine-grained. Unsurprisingly, the maximum ISO of 2048, 000 is very noisy with a strong chroma component, and is thus best avoided.

Color balance with Auto white balance was quite good which isn't always the case, with just a slightly cool bias. At the highest ISO though, color balance shifted towards magenta in midtones and shadows for two of the three shots, but oddly the center 1/16 foot-candle shot with default noise reduction was underexposed and didn't display the magenta shift.

We did not detect any significant issues with hot pixels or heat blooming, though some horizontal banding (fixed pattern noise) can be seen at the highest ISO, however that isn't uncommon at such a high sensitivity, and we didn't see it at the lower ISOs tested, even in the shadows.

LL AF: The Pentax K-1's phase-detection autofocus system was able to focus on our standard low-contrast AF target down to well below the 1/16 foot-candle light level (-3.4 EV) using an f/2.8 lens with its AF assist light turned off, which is excellent, easily meeting Pentax's spec. And with our high-contrast AF target, it was able to focus down to an amazing -5.4 EV. With the AF assist lamp enabled, the K-1 was able to focus in complete darkness on both targets. In Live View mode, the K-1 was able to focus down to -1.3 EV on our low-contrast AF target, and down to -3.3 EV on our high-contrast target, which is quite good.

How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.

NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) Digital SLRs like the Pentax K-1 do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.

Print Quality
Excellent 30 x 40 inch prints and larger at ISO 100/200/400; a good 20 x 30 inch print at ISO 1600; a nice 8 x 10 inch print at ISO 12,800.

ISO 100/200/400 images printed at 30 x 40 inches are simply stunning. The level of fine detail and "pop" in these prints rivals most any model that's passed through our test lab. Wall display prints are possible at larger sizes, until resolution catches up and individual pixels become noticeable, which given the 36.2-megapixel files would not be until very large prints indeed.

ISO 800 prints are quite nice at 24 x 36 inches. Crisp, fine detail and rich colors are still present at this size, and only the faintest trace of noise is evident in flatter areas of our test target. There's also a typical softening in the red channel, common on most all digital cameras to varying degrees as ISO begins to rise.

ISO 1600 yields a 24 x 36 inch print that almost passes our "good" grade. There is now a bit more noise evident in the shadowy areas of our target, although it's more akin to film grain than mottling as some cameras produce, but enough to warrant only using this size for less critical applications. A reduction to 20 x 30 inches does the trick and allows for good prints at this sensitivity.

ISO 3200 is capable of delivering a very nice 16 x 20 inch print, with only minor issues such as a trace of noise apparent in flatter areas of our target. Also, all contrast detail is now lost in our tricky red-leaf swatch, a fairly common theme as ISO rises, but otherwise the print still shows good fine detail and color reproduction is still quite good.

ISO 6400 tends to be the turning point for most full-frame cameras in terms of image quality, and the K-1 is no exception. While the 13 x 19 inch print is not bad, and certainly usable for less critical applications, a reduction in size to 11 x 14 inches is required in order to tighten the prints up enough to warrant our good seal. There are only minor issues similar to the ones mentioned above, but otherwise a nice print. Anything larger introduces too much noise in some areas to make our good grade.

ISO 12,800 prints a nice 8 x 10, which is still a very useful size for such a high sensitivity. It's only been in the past few years that we've awarded a few cameras with larger prints here, with a few Nikon and Sony bodies that have scored an 11 x 14 inch rating.

ISO 25,600 produces a 5 x 7 inch print similar to the 8 x 10 at ISO 12,800. There's still plenty of fine detail and full color reproduction, with very few issues to speak of. Not a large print, but it's nice to know you can achieve a good 5 x 7 at such a lofty gain setting!

ISO 51,200 images show just a bit too much noise in the 4 x 6 inch prints to call good, but they're fine for less critical applications. Still, this setting is best avoided for printing.

ISO 102,400/204,800 do not produce worthwhile prints at any size and these settings are best avoided.

The 36-megapixel full-frame Pentax K-1 abounds with the potential to deliver stunning prints at the lower ISOs, and your printer will love you for it. As the gain rises the K-1 continues to offer the ability to produce large prints all the way to a 16 x 20 at ISO 3200. After that, the camera becomes a mere mortal again but still delivers about as good as most other full-frame models we've tested, though not as good as some of them. However when employing PSR mode you'll gain even more resolution and lower noise, and can therefore produce even larger prints. Given the excellent single-shot printing performance up to ISO 3200, we give the Pentax K-1 high marks in the print quality department.