Nikon Z7 Image Quality
Color
Saturation & Hue Accuracy
Vibrant colors with slightly below average hue accuracy.
ISO Sensitivity
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In the diagram above, the squares show the original color, and the circles show the color that the camera captured. More saturated colors are located toward the periphery of the graph. Hue changes as you travel around the center. Thus, hue-accurate, highly saturated colors appear as lines radiating from the center. Mouse over the links above to compare ISOs, and click to load a larger version. |
Saturation. The Nikon Z7 pumps dark blues a lot, dark greens and reds are moderately pushed while most other colors slightly boosted, but it undersaturates yellow and cyan tones slightly when using default settings. Overall, mean saturation is a little higher than average at 112.5% or 12.5% oversaturated at base ISO versus a more typical 10%. The Z7's mean saturation is stable up to ISO 6400, but gradually falls at higher ISOs to a minimum of 105.8% at the maximum extended ISO of 102,400. That's still pretty good, though, as many cameras dial back saturation more significantly at higher ISOs to help manage chroma noise. 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. The Nikon Z7's rendering of Caucasian skin tones in "sunlit" outdoor lighting when using default Auto white balance was slightly on the warm, yellow side. Manual white balance on the other hand produced much more pinkish and healthy-looking skin tones. 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 Nikon Z7 produces a few color shifts relative to the accurate translation of colors in its images, as do almost all cameras. Cyan has a pronounced shift toward blue (we think it's a deliberate choice by camera engineers to produce better-looking sky colors), reds are shifted slightly toward orange while dark orange and yellow are slightly shifted toward red. Mean "delta-C" color error at base ISO was 6.23 after correction for saturation, which is a bit higher than average (lower numbers are better), but it remained below 7.0 across the ISO range which is good. Note that the above results were obtained with custom white balance in simulated daylight. See the "Indoors, incandescent lighting" section below for how the Z7 performed in tungsten lighting. Hue is "what color" the color is.
See full set of test images
with explanations See thumbnails of all test and gallery images |
Sensor
Exposure and White Balance
Indoors, incandescent lighting
The Z7 struggled a bit to produce a neutral color balance under incandescent lighting using presets or manual (custom) white balance. No exposure compensation required.
Auto WB (Default) 0 EV |
Auto WB (Keep White) 0 EV |
Auto WB (Keep Warm) 0 EV |
Incandescent WB 0 EV |
2,600K WB 0 EV |
Manual WB 0 EV |
Indoors, in typical incandescent lighting, color balance with the default Auto "Keep overall atmosphere" option was warm but not too bad (we've seen a lot warmer, and some users may prefer this look as being more representative of the actual lighting). The "Keep white" Auto white balance setting was pretty good but a bit cool and magenta, while the "Keep warm" option was very warm and orange as expected. The Incandescent setting was also quite warm but with more of a yellow/green tint. The 2,600 Kelvin setting which should match our lighting was fairly neutral, but with a slight green bias. Oddly, the Manual (Custom) white balance setting was almost as warm as the default Auto white balance, despite attempting to obtain better results several times. However, you can always tweak the color temperature or use the WB fine-tuning feature to better match your lighting. The Z7 required no exposure compensation for this shot while most cameras need about +0.3 EV, though the resulting image is a bit dim (however +0.3 EV was too bright and we don't adjust our lights 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
Vibrant color with good exposure outdoors, but high default contrast.
Manual White Balance +0.7 EV |
The Nikon Z7 generally handled tough outdoor lighting under harsh sunlight well in terms of color and exposure. We found skin tones a touch yellow in our "Sunlit" Portrait shot with auto white balance, though, so we preferred the more pinkish skin tones produced when using manual (custom) WB. Default contrast is quite high, so some highlights were clipped in the mannequin's shirt, some of the flowers and even in her nose, though deep shadows contain excellent detail and are relatively clean here at base ISO. The Z7 required +0.7 EV exposure compensation to keep the face and eyes reasonably bright, which is about average for this shot.
Resolution
>4,000 lines of strong detail.
Our laboratory resolution chart reveals sharp, distinct line patterns all the way up to the 4,000 lines per picture height limit from both in-camera JPEG and ACR converted RAW files in both directions. The in-camera JPEG shows more obvious aliasing in the form of strong luminance moiré patterns starting at about 3,100 lines, though, however color moiré is well-controlled. The ACR conversion shows less obvious luminance moiré than the in-camera JPEGs, but color moiré patterns are quite evident, even at lower resolutions. 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.
Sharpness & Detail
Very sharp images with exceptional detail, though with minor sharpening halos and aliasing artifacts. Minimal noise suppression artifacts at base ISO.
Sharpness. The Nikon Z7 produces incredibly sharp, exceptionally detailed images at default settings, though edge enhancement artifacts are visible around high-contrast subjects, such as the fairly minor sharpening halos around the lines and lettering in the crop above left. Default sharpening is similar to the D850 which is to say a little strong but still quite pleasing, and you can always turn it down or tweak other settings such as mid-range sharpening and clarity to taste. 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 minimal detail loss due to noise suppression, as the darker areas of the mannequin's hair show a lot of detail. Individual strands are still distinguishable even in the lighter shadows, though some begin to merge as shadows deepen, and in places where the tone and color of adjacent strands is very close. The hair is also virtually free from chroma noise, but some strands do show signs of the "jaggies" and other aliasing artifacts. Still, an excellent performance 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.
Shutter Shock. The Nikon Z7's shutter mode defaults to fully mechanical, and this is unfortunate because like other mirrorless cameras we've tested in mechanical shutter mode (such as the Sony A7R III, Canon EOS R and various APS-C and Micro Four Thirds cameras), the Z7's mechanical first curtain shutter can cause some blurring due to "shutter shock". (Mirrorless cameras tend to suffer from shutter shock more than DSLRs, because their mechanical shutters need to close before opening again for the exposure, while DSLRs start with a closed shutter (unless in live view mode), so they only need to open them at the start of the exposure which theoretically doesn't generate as much vibrations as closing the shutter and then immediately opening it again). Most other manufacturers default to Electronic Front Curtain Shutter (EFCS) these days to avoid blurring from shutter vibrations, however the Z7's EFCS mode limits the top shutter speed to 1/2000s and the top ISO to 25,600 so the Z7 defaults to mechanical shutter so as not to limit exposure settings.
Mechanical shutter shock | ||
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Shutter Mode:
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Above, you can compare the difference in sharpness between mechanical shutter and EFCS modes at 1/80s and ISO 800 with an adapted Nikkor 60mm f/2.8G at f/8 by mousing over the blue text. (Fully electronic shutter mode was practically identical to EFCS.) The blurring is pretty obvious here, but the amount varies with shutter speed, lens used, whether the FTZ adapter is used, how the camera is mounted (on a study tripod here), etc. The example above was about the worse we've seen from the Z7, and using the native 50mm f/1.8 S lens produced much less blurring under the same conditions.
Since this was no real surprise we haven't fully characterized the Z7's mechanical shutter shock in terms of the range of affected shutter speeds, impact of lens used, IBIS modes, etc., but we did notice it at shutter speeds as low as about 1/10s and as high as about 1/400s in our initial investigation (though it was very subtle at those extremes) before we switched over to EFCS for all our lab shots when possible.
What the Z-series needs is an Auto Shutter mode that defaults to EFCS but switches over to mechanical shutter speeds automatically to access shutter speeds higher than 1/2000s or ISOs above 25,600 where EFCS is not supported and shutter shock is not an issue. Here's hoping a future firmware update will implement that kind of feature.
Update 07/12/2019: On May 16, 2019 Nikon released firmware v2.00 for the Z7 (and Z6), which among other improvements adds an Auto Shutter mode! As hoped, this new feature is designed to avoid shutter shock by switching between EFCS and fully mechanical shutter automatically as needed. We've briefly tested it, and have determined at shutter speeds of 1/250s and below Auto Shutter mode uses EFCS while higher shutter speeds use the fully mechanical shutter. While we did not investigate if the switch-over shutter speed varies with the lens used or when IBIS is enabled, etc., the new feature appears to work as intended. So be sure to upgrade and use Auto Shutter mode if you want to "set and forget" to avoid shutter shock and still access the camera's full range of shutter speeds and ISO sensitivity.
RAW vs In-Camera JPEGs
As noted above, the Nikon Z7 does a great job at producing crisp images with tons of fine detail in its JPEGs. Let's see how a RAW conversion using our standard converter (Adobe Camera Raw) at base ISO compares:
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 via DNG Converter 11.1 using the default camera profile and noise reduction with some moderate unsharp mask sharpening applied in Photoshop (250%, radius of 0.3 pixels, and a threshold of 0).
Here, we can see that Adobe Camera Raw combined with moderate sharpening in Photoshop delivers slightly finer detail than the camera JPEG, with fewer sharpening halos around high-contrast edges. (The Z7's lack of an anti-aliasing filter means it's more prone to aliasing artifacts such as moiré patterns, as seen in the red-leaf fabric above.) Noise is slightly more visible in the ACR conversion (default NR used), but is still very low. Contrast is higher from the in-camera JPEG and colors are warmer and more saturated compared to the Adobe Standard profile used, though plenty of camera profiles are available in ACR including Vivid, Standard, Neutral, Portrait, Landscape and Flat.
Bottom line: The Nikon Z7's default JPEG processing produces excellent detail and crispness at base ISO and default settings, though contrast and saturation are on the high side. As is usually the case, you can extract additional detail with lower sharpening artifacts when carefully processing RAW files.
ISO & Noise Performance
Very good high ISO performance.
Noise Reduction = Default | ||
ISO 32 | ISO 64 | ISO 100 |
ISO 200 | ISO 400 | ISO 800 |
ISO 1600 | ISO 3200 | ISO 6400 |
ISO 12,800 | ISO 25,600 | ISO 51,200 |
ISO 102,400 |
Nikon Z7 images are very crisp and clean at ISOs 32 through 800, with almost no chrominance noise and just a touch of luminance noise becoming more visible in the shadows as ISO increases. ISO 1600 shows a bit more luminance noise than lower ISOs, but is still quite clean and detailed. ISO 3200 is probably the first sensitivity where there is noticeable luma noise and blurring due to noise reduction when viewed at 100% magnification, though noise is still very fine-grained and chroma noise is still very low. ISO 6400 shows stronger smudging with more visible luma noise and noise reduction artifacts, but fine detail is still pretty good and chroma noise is still well controlled. ISO 12,800 still offers good detail versus noise for such a high ISO, however luminance noise starts to look a little artificial. Image quality drops off rapidly at ISO 25,600 and above, with high luma noise, strong blurring and other noise reduction artifacts, as well as progressively stronger chroma noise in the form of yellow and purple blotching.
Still, high ISO performance is very good for a full-frame camera, especially considering the very high resolution. 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 led to some blown highlights in default JPEGs. RAW files show excellent dynamic range, but banding is sometimes visible in deep shadows. Excellent low-light performance, capable of focusing in near darkness.
+0.3 EV | +0.7 EV | +1.0 EV |
Sunlight. Surprisingly, the Nikon Z7 struggled a little with the deliberately harsh lighting in the above test, because of its somewhat high default contrast. We felt that the default and +0.3 EV exposures were too dim, while +1.0 EV blew too many highlights. The best overall exposure was +0.7 EV but it still led to some blown highlights in her shirt, flowers and even her nose. There are also some dark shadows at +0.7 EV, but detail in them is excellent and shadow noise is relatively low for the resolution. Note that these shots were captured with the Nikon Z7's Active D-Lighting control set to its default of "Off", and enabling it would have likely preserved all highlights even at +0.7 EV. See below for how Active D-Lighting helps with hot highlights and dark shadows.
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.)
100% crop of shadow area in ACR converted ISO 64 NEF file with +3.0 EV exposure boost applied. |
PDAF banding in shadows. Faint bands or stripes that are darker than the surrounding area are sometimes visible in dark shadows (vertical in the crop here taken in portrait mode; they would obviously be horizontal in landscape mode), especially in NEF files after exposure is lifted significantly, an artifact related to the Z7 sensor's integrated PDAF pixels. The crop to the right was taken from the default exposure "Sunlit" Portrait (Z7OUTBAP0) NEF file converted in ACR with +3.0 EV exposure compensation applied. As you can see, there are faint vertical bands which will limit usable dynamic range in shadows to a degree. We think it's a fairly minor issue, though, and perhaps Nikon will reduce or eliminate them in a future firmware update (some raw converters such as Raw Therapee already have a PDAF lines filter as this is not unique to the Nikon Z series). But it's really up to you to decide whether it is a significant enough issue to be concerned about.
Active D-Lighting
Active D-Lighting attempts to preserve detail in both highlights and shadows in high-contrast situations, while maintaining moderate levels of contrast. The series of shots below show the effect of the various Active D-Lighting settings (Off (default), Low, Normal, High, Extra High and Auto) available on the Nikon Z7 on our high-contrast "Sunlit" Portrait scene.
Note that Active D-Lighting is different from the Retouch menu's D-Lighting, as it is performed during image capture instead of after. (It does affect only JPEG images, though, Nikon very properly doesn't apply tonal adjustments like this to RAW file data. NEF files are however tagged so that Nikon software can automatically apply the effect when converted.)
"Sunlit" Portrait Active D-Lighting (0 EV)
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ADL Settings: Off (Default) Auto Low Normal High Extra High |
Mouse over the links to see how the various levels of Active D-Lighting affects our "Sunlit" Portrait shot at default exposure, and click on any link to get to the full-res image. (Active D-Lighting's effect can be a little subtle in shots like those above, so we decided to use a mouse-over with matching histograms to better show how each setting compares.)
As you can see from the thumbnail images and histograms above, Active D-Lighting boosted shadows and deeper midtones while highlights were maintained and even reduced at higher settings. As mentioned previously, the default ADL setting for the Z7 is Off, while in more consumer-oriented Nikons the default is Auto.
HDR Mode
Like more recent Nikon DSLRs, the Z7 offers an in-camera high-dynamic-range imaging function. When enabled, the Z7 captures two images with one push of the shutter button -- one underexposed and one overexposed -- and combines them in-camera to produce a high-dynamic-range JPEG. (RAW format is not supported.) There are three exposure differentials available: 1, 2 and 3 EV, as well as an Auto option, and there are three Smoothing options: Low, Normal and High. You can also elect to do a series of HDR shots without having to re-enable the mode each time, or select a Single Photo option.
"Sunlit" Portrait HDR (0 EV)
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HDR Settings: Off Auto 1 EV 2 EV 3 EV |
Mouse over the links to see how the Auto, 1 EV, 2 EV and 3 EV levels of HDR with default Normal Smoothing compare. Click on a link to get to the full-res image.
As you can see, Auto produced an effect somewhere between 1 and 2 EV with this scene, but all four settings worked as expected without producing ugly "HDR halos" using the default smoothing setting. Obviously moving subjects should be avoided, as you can run into ghosting of objects in HDR shots. We think Nikon Z7's HDR feature is one of the better in-camera implementations, however you can most certainly do better by bracketing more exposures and combining the images yourself.
Dynamic Range (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.) 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 Nikon Z7's dynamic range test results to its close DSLR sibling's, the D850, and to the Sony A7R Mark III's.
As you can see, the Z7's dynamic range (in orange above) is similar to that of the D850 (yellow), which isn't a surprise given they share very similar though not identical sensors. Peak dynamic range at the lowest ISO is nearly identical at 14.6 versus 14.8 EV for the D850, despite the very faint banding present in very dark shadows due to PDAF pixels. Interestingly, the Z7's dynamic range isn't as high as the D850's between ISO 100 and 400, trailing it by almost 3/4 EV at the ISO 200 setting. But from ISO 400 to 25,600, dynamic range is practically identical, however the Z7 falls behind the D850 again at the very high ISOs of 51,200 and 102,400.
The Sony A7R III's dynamic range tested higher than the Z7's across the ISO range except at ISO 400, where they are practically identical. Peak dynamic range from the Sony was about 14.7 EV vs 14.6 which is a negligible difference and partially due to the Z7's lower ISO 32 setting. However, between ISO 100 and 200 the Sony tested up to about 0.7 EV higher, and at ISO 800 through 25,600, the A7R III tested up to about 2/3 EV higher, while at very high ISOs the Sony pulled ahead by up to almost 1.7 EV.
Bottom line: Excellent dynamic range for a full-frame camera, though not quite as good as the class-leading D850 at low ISOs, nor as good as the Sony A7R III at most ISOs. Click here to visit the DxOMark page for the Nikon Z7 for more of their test results and additional comparisons.
Low-Light AF: In the lab, the Z7's hybrid autofocus system was able to focus on our legacy low-contrast AF target reliably down to only about -2.0 EV unassisted with an f/2.8 lens, but it was able to focus on our newer high-contrast target down to -6.4 EV which is very good. Using the Z7's Low-light AF mode improved those results dramatically, though, down to about -8.0 EV with our low-contrast target and to below -8.0 EV (the lower limit of our light meter) using the high-contrast target. Excellent results here. Note that unlike the D850, the Z7 does have a built-in AF illuminator which will allow it to focus in complete darkness as long as the subject is within range and has sufficient contrast.
Update 07/12/2019: On May 16, 2019 Nikon released firmware v2.00 for the Z7 (and Z6), which among other things improves low-light AF performance. We've now retested the Z7's low-light AF limits with v2.00 firmware and found it did improve low-light autofocus in our lab tests, so the above figures have been updated to reflect better results with v2.00 firmware.
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.) Mirrorless cameras like the Nikon Z7 do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.
Output Quality
Print Quality
Excellent 30 x 40 inch prints at ISO 32-800; a nice 24 x 36 at ISO 3200; a good 11 x 14 at ISO 12,800.
ISO 800 also yields an exceptional 30 x 40 inch print, almost as good in quality as the lower ISOs. Even the 36 x 48 inch prints here are fine for wall display purposes, as this camera doesn't produce common, ordinary ISO 800 prints!
ISO 1600 prints are also quite good at 30 x 40 inches, which is really pushing the bounds for most full-frame cameras. The Z7 handles it with aplomb, as there is a wealth of fine detail at this size with virtually no noise evident in the print, and very little softening as yet occurring in the red channel.
ISO 3200 delivers a 30 x 40 inch print that amazingly almost passes our good seal, and that would have been a first for a full-frame camera! They certainly will work for less critical applications or casual wall display purposes, but for more critical printing we can safely give our seal of approval to the 24 x 36 inch prints here, which are quite good in most respects.
ISO 6400 produces a 16 x 20 inch print that is quite good for such a relatively lofty ISO. This is where the benefit of a quality full-frame camera really begins to shine, as most crop-sensor (APS-C/MFT) cameras can't come close at ISO 6400. There is mild noise in flatter areas of our test target, and some mild softening present in the red channel, but still a very nice print overall at this size. And for your ultra-critical printing purposes, the 13 x 19's tighten up even more.
ISO 12,800 yields a 13 x 19 inch print that almost passes our good grade, and that would be yet another first for a full-frame camera at this sensitivity. The 11 x 14 inch prints here are quite good, with only typical minor issues associated with such a high ISO and mild traces of noise in a few areas, but noise is still well-controlled.
ISO 25,600 allows you to almost shoot in the dark and still deliver a good 8 x 10 inch print, and that is really saying something. There is still good color representation and plenty of fine detail, and that's simply not something we're accustomed to seeing at ISO 25,600!
ISO 51,200 tends to bring even the best of full-frame cameras down to mere mortal status, and the Z7 is no exception. The 5 x 7 inch prints here just barely pass our good seal, but there is some minor scorching going on with the colors, and mild traces of noise. For the most part, the camera is meant to be used at ISO 25,600 and below, unless a 5 x 7 inch print is all you'll need.
ISO 102,400 comes oh-so-close to producing a usable 4 x 6 inch print, but it just barely misses the mark. It's not a bad print for casual use, but there's just not enough fine detail nor full colors to make our good seal.
Well done, Nikon Z7! Your printing prowess is superb and your walls will love you for it. From extended low ISOs all the way to ISO 6400 the prints are outstanding, and even at the lofty ISOs of 12,800 and 25,600 you can achieve good prints at reasonable sizes. Indeed, these prints are a shining example of why we named the Nikon Z7 our 2018 Professional Camera of the Year!
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Nikon Z7 Photo Gallery .
Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Nikon Z7 with those from other cameras you may be considering. The proof is in the pictures, so let your own eyes decide which you like best!
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