Nikon D90 Image Quality

Saturation & Hue Accuracy
Better than average accuracy and pleasing color overall.

Saturation. The Nikon D90 oversaturates some blues, reds and greens a bit, and actually undersaturates some cyans and purples. The net effect is pleasing and accurate color, actually somewhat more in keeping with the demands of professional users than that of other recent Nikon SLRs intended for consumers. If you'd like a bit brighter-looking color, it's easy enough to dial in a bit more saturation in the D90's Picture Styles menu; the steps there are a bit bigger than we'd optimally like to see, but the +1 or +2 saturation setting should please most people looking for slightly brighter color, without going too far. 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. Professional models tend to be more restrained in their color rendering.

Skin tones. The Nikon D90 rendered skin tones just slightly warm/pink. Still, the results looked natural, well within what we'd consider an acceptable range. (Here, too, the D90's saturation adjustment may come into play for some users, letting them knock down the color on skin tones a little, if they find the default rendering a bit too saturated for their personal tastes.) 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. With an average hue error after correction for saturation variation of only 4.21 delta-C units, the D90's hue accuracy is very good; closer to technically accurate than many (most?) DSLRs on the market. All in all, accurate and pleasing color. Hue is "what color" the color is.

Saturation Adjustment
The Nikon D90 lets you adjust the image saturation, contrast, and sharpness in seven steps each. As can be seen below, the saturation adjustment worked very well, providing a reasonably fine-grained adjustment over a useful range of control. (While we'd personally like to see just slightly smaller steps, the Nikon D90 gives an excellent degree of control.) The saturation adjustment also has almost no impact on contrast. That's how it should work, but we've often found interactions between saturation and contrast (and vice versa) on the cameras we test.

Exposure and White Balance

Indoors, incandescent lighting
Good color with the Manual and 2,600K white balances. About average positive exposure compensation required.*

The Nikon D90's auto white balance had a difficult time with the very warm color balance of the household incandescent bulbs used in this shot, and its incandescent white balance setting is obviously tuned for the cooler 3,200K color of professional studio lighting. The 2,600K and Manual settings produced much more accurate results. Skin tones and white values looked best with the manual option, as the 2,600K setting was just a hint cool (though still nearly accurate - and we could obviously have chosen a slightly higher setting if we'd wanted to fiddle with it more). The Nikon D90 required a +0.3 EV increase in exposure (with a Nikkor 24-70mm f/2.8G lens) to get best results, 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.  

* Note: These shots were captured with a Sigma 70mm f/2.8 macro lens, one of the sharpest lenses we've ever tested on SLRgear.com. We use Sigma 70mm lenses in most of our studio test shots because they are so sharp and are available on all major platforms with the exception of Four Thirds. For some reason, though, on some (but not all) Nikon bodies, the Sigma causes the camera's exposure system to overexpose by somewhere between two thirds of a stop and a full stop. The D90 is one such body, as the exposure compensation settings used in the images above are lower than normal for this shot, so the comments regarding exposure compensation required have been adjusted to match results we got with a Nikkor lens. Other than this exposure shift, the Sigma 70mm performs very well on Nikon bodies, so we continue to use it as our "reference" lens, due to its excellent optical qualities.

Outdoors, daylight
Good exposure and color outdoors, though slightly high contrast at the default setting. Very good highlight/shadow detail preservation, though, and options like D-Lighting, Contrast, and Saturation are a help when faced with tough conditions like these.

The Nikon D90 handled tough outdoor lighting under harsh sunlight pretty well, and produced good overall color and exposure. The default contrast setting was a bit on the high side, but shadow and highlight detail in the Portrait shot was excellent. The house shot was slightly overexposed, losing some of the highlights, but the camera's contrast and D-Lighting options helped in these harsh lighting conditions. (See the full range of contrast, saturation and D-Lighting options further down the page, in the "Extremes" section below.) Color looks good outdoors as well.

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

Resolution
Very high resolution, 1,700 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns all the way down to about 1,700 lines per picture height in both directions, which is excellent. (Some would doubtless argue for an even higher lines/picture height rating, but we judge the aliasing that appears shortly after 1,700 lines as an indication that 1,700 is about the limit of the camera's true resolution.) Extinction of the pattern occurred at around 2,500 lines. Use these numbers to compare with other cameras of similar resolution, or to see just what higher resolution can mean in terms of potential detail.

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

Sharpness & Detail
Very detailed images, though slightly soft overall. Minor edge-enhancement on high-contrast subjects and minimal noise suppression.

Sharpness. The Nikon D90 captures a lot of fine detail, but its images are a bit on the soft side at default settings. Some very slight edge-enhancement artifacts are visible on high-contrast subjects such as the crop above left, but they're really pretty minimal. D90 images take sharpening in Photoshop and other software pretty well. You'll do somewhat better if you process the Nikon D90's images straight from the NEF RAW files. Overall though, detail is excellent.

Detail & Noise Suppression. The crop above right shows some noise suppression in the shadows at ISO 200, but individual strands of hair can be seen even in relatively low-contrast areas. 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.

JPEG vs RAW

Mouse over the links in the box above to compare the difference in sharpness and detail from camera JPEG versus a RAW file processed with Nikon's View NX version 1.1.1 and Capture NX2 version 2.1.0. Camera settings for the JPEG settings were the defaults.

We've found that generally there is indeed a good reason to shoot RAW, because RAW files have more detail than makes it out in the camera-produced JPEGs. This seems also to be the case for the Nikon D90. Its in-camera JPEG processing is actually pretty good, but you can nonetheless produce a sharper, more finely-rendered image by manipulating the RAW files in a good third-party RAW converter - and Nikon's Capture NX2 seems to hold its own with Adobe Camera Raw, at least in terms of detail.

The camera's own JPEG processing and that of Nikon's View NX produce very similar-looking images (no surprise there), but Nikon Capture NX2 gives you more control over image-sharpening parameters and the result can be quite a significant increase in sharpness. It wasn't mentioned in the release notes for Capture NX2 version 1.2, but the sharpening operator now seems to be much less constrained than it was in earlier versions, now letting you set quite a tight operator.

The examples above also include a crop from an Adobe Camera Raw conversion, using the release beta of ACR version 4.6. As usual, we imported the RAW image into Photoshop via ACR with the sharpening in ACR turned off entirely, then applied very strong/tight unsharp masking in Photoshop.

ISO & Noise Performance
Good noise performance, with low noise levels and good detail up to ISO 1,600.

Noise levels are quite low at the Nikon D90's lower ISO settings, and really quite reasonable even at ISO 800. At ISO 1,600 noise levels increase with more blurring in the fine details and visible "grain", but there is still quite a bit of detail. At ISO 3,200, blurring is stronger with more noise-reduction artifacts, but the grain pattern is still quite tight and results compete well with the performance of dSLRs in its price range from other manufacturers at that ISO level. ISO 6,400 is quite noisy with purple and yellow blotchiness, bright noise pixels as well as much stronger blurring of fine detail. (See our High-ISO comparison page for a detailed comparison between the D90 and D300's High-ISO performance.)

Extremes: Sunlit and low light tests
Very good detail in both highlights and shadows, high resolution and good overall exposure. Very good low-light capabilities as well.

Sunlight. The Nikon D90 did very well under the deliberately harsh lighting in the test above. The best exposure is probably that at +1.0 EV: The mannequin's skin tones are at a good level, and even the brightest parts of her shirt aren't really blown out. (Check the file in an image editor, there's detail in even the strongest highlights, if you play with the Levels or Contrast/Brightness adjustments.)

The image looks a little contrasty, but that's just representative of the lighting itself. The key is that highlight and shadow detail are both very well preserved, with good-looking midtones as well. - Not even the brightest highlights of the shirt are lost, while at the other end of the tonal scale, the very darkest shadows are only slightly plugged and posterized. Noise and noise suppression are quite low in the shadows, and fine detail in these areas looks very good. Still, the camera's adjustable contrast, saturation and D-Lighting adjustments do help fine tune the exposure for conditions like this. (As always though, we remind readers to be sure to use fill flash in situations like the one shown above; and it's better to shoot in the shade when possible.)

The series of shots above show the results of the different contrast settings, all shots captured at an exposure setting of +1.0 EV. While it can be difficult to evaluate small differences in contrast on small thumbnails like these, it's pretty easy to see the impact of the Contrast adjustment in the images above. At its lower settings, the D90 did a really excellent job of handling the deliberately horrific lighting of this shot. The deep shadows are a bit noisier than I'd like, but I'd also much prefer that the noise be left in there, rather than flattening it out and taking all the subject detail with it. It's important to note too, though, that the areas where the noise becomes evident are way, way down at the extreme shadow end of the tone curve; RGB brightness levels of 20 and below. Like the Saturation adjustment, the control for Contrast is quite effective, and interacts very little with color saturation.

Active D-Lighting The Nikon D90 offers four levels of Active D-lighting (vs the D300's three levels and none on the D80), plus the default Off setting. Nikon's Active D-Lighting does a good job at preserving highlights while bringing up detail in the deep shadows, though not surprisingly, more noise is visible in the darker areas of the test shots above. (Active D-Lighting's effect is a little in shots like those above, that have broad areas of both very bright highlights and very deep shadows - You'll notice more impact in shots that are over- or underexposed overall, or where the central subject is in shadow from significant backlighting.)

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.)

Low light:
The Nikon D90 turned in a very good performance here, capturing bright images at the lowest light level even at the lowest sensitivity setting. Color balance is a bit cool and purplish from the Auto white balance setting, especially at the darkest light levels. The camera's handling of noise was very good, with minimal noise artifacts and good detail up to ISO 1,600. Noise was moderate at ISO 3,200, and a little high at ISO 6,400, along with quite a few hot pixels. The AF system was able to focus unassisted down to just below the 1/16 foot-candle light level, and to total darkness with the AF assist enabled.

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 Nikon D90 do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.

Print Quality
Excellent print quality, great color, good 20x30 inch prints, excellent 16x20 inch ones. ISO 3,200 images are surprisingly good at 8x10, even better at 5x7.

Output from the Nikon D90 was good enough to produce good-looking 20x30 inch prints, and sharp 16x20 inch ones. As noted elsewhere in this review, the D90 rewards RAW shooters with really excellent detail when its NEF files are processed through a good RAW converter. The difference between camera JPEGs and those from RAW isn't as stark as with some cameras we've tested, but the results are well worth the effort if you care about extracting every last bit of information from your images.

High ISO images were better than we'd expected, the D90 clearly has an edge on the D80 in terms of high-ISO noise performance despite the new model's smaller pixels. We'd estimate the noise improvement as being somewhere around a half to two-thirds of a stop at the highest ISO levels (3,200 and 6,400); it's clearly better, but when we compare images shot with the D90 with those shot by the D80 at half the ISO, it seems that there's less than a full stop of difference. It's not far off that mark, though. Oddly, this advantage largely disappears at lower ISO settings, to the point that we think the D80 does better at ISO 1,600. Besides the noise levels themselves though, the D90's images at very high ISOs have quite noticeably improved color over those of the D80. Reducing color saturation is a common tactic used to mask noise, and the D90 does it far less than its predecessor.

The Nikon D90's noise processing at high ISOs varies quite a bit, depending on the setting you're using. With the D80, we liked its "Low" noise reduction setting the best, but with the D90, we found that images shot with the Low setting in some cases looked worse than ones shot using "Off". Our recommendation would be to shoot with the Normal setting for images being used straight from the camera, and use Off if you're going to be post-processing with a third-party noise reduction program. The High setting leaves images very clean, but also pretty soft, with a lot of fine detail gone. As noted, the Low setting was our favorite, it produced surprisingly clean images that still contained loads of fine detail.

Overall, the Nikon D90 does quite well at high ISOs. You could arguably use its ISO 3,200 shots to make 13x19 inch prints suitable for wall display, but they'll look much better as 8x10s. (Surprisingly clean, albeit with some loss of subtle detail. We think most readers would be quite pleased with 8x10s from the D90's ISO 3,200 images.) At ISO 6,400, the D90's images are too noisy to use for 8x10 inch prints, but they look just fine at 5x7 inches.

Color-wise, the Nikon D90 did very well. At its default settings, its colors (particularly reds) are a bit more saturated looking than those of the D80, but we think they'd fall within an acceptable range for most shooters. Green and orange shades in particular are also brighter than the D80's somewhat undersaturated handling of those colors, but the overall effect is pretty pleasing. (If you like less-saturated color, just take the saturation adjustment down a notch.) Hue accuracy is also good, better than that of the D80 by a nose. A very good performance overall.

Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon Pro9000 studio printer, and on the Canon iP5200 here in the office. (See the Canon PIXMA Pro9000 review for details on that model.)