Nikon D40 Image Quality

Resolution
Moderately high resolution, 1,300 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,300 lines per picture height, with extinction at around 1,850 horizontally, and about 1,700 vertically. (1,250 lines horizontally might be a more conservative call though, as there are a lot of aliasing artifacts to be found at 1,300 line in the crop below left.) 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. Beware that while you might be able to make out what look like distinct lines at numbers higher than those we've mentioned here, the camera is just doing its best to continue interpreting the lines. So the lines you see at 1,550 and higher are really only artifacts generated by the camera's imaging system.

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

Sharpness & Detail
Slightly over-aggressive edge enhancement on high-contrast subjects and minor detail loss to noise suppression in the shadows, but good detail overall.

The Nikon D40 captures sharp images, but does produce some slight edge enhancement artifacts on high-contrast subjects such as the crop above left. (Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.)

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. The crop above right shows some minor detail loss to noise suppression in the deeper shadows, but there's really less than average overall.

Saturation & Hue Accuracy
Good overall color, slight oversaturation of strong reds and blues, slight undersaturation of yellows and greens.

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. The Nikon D40 does oversaturate the strong red and blue tones a little, but by relatively modest amounts. (The red oversaturation is a little high, but by no means the most we've seen in a consumer DSLR. The D40 also undersaturates some yellows and greens slightly, but the rendering of these colors didn't strike us as flat or dull-looking. Overall, we'd rate the D40's color as very good. 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. Here, the D40 did render skin tones with a slight pink cast, but results were still quite pleasing. (Here again, consumers tend to prefer Caucasian skin tones that are just a bit pinker than in real life, the slight pinkish cast being interpreted as a "healthy glow." We think most users would find the D40's skin tones very pleasing.)

The other important part of color rendition is hue accuracy. Hue is "what color" the color is. The Nikon D40 did push blue toward cyan a little (which produces better-looking skies), and dark blue toward violet, but again, the overall results are pretty good.

Exposure and White Balance

Indoors, incandescent lighting
Excellent color with the Manual white balance setting, though a hint red. Auto white balance very yellow, incandescent on the edge of acceptable. About average positive exposure compensation required.

Color balance indoors under incandescent lighting was too warm with the Auto white balance setting, and the Incandescent setting also produced warm color, though not as strong of a cast. (Some users may find the results from the Incandescent setting acceptable, it was just a bit too warm for our tastes.) Despite a slight reddish tint, the Manual option produced very good-looking results overall. The Nikon D40 required about average positive exposure compensation here, at +1.0 EV, though some users might prefer the more controlled highlights of the +0.7 EV exposure. Overall color is quite good, despite the slight red tint that mainly effects the skin tones, though the blue flowers in the bouquet have a very strong purple tint. (A common occurrence with 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 overall, though a tendency toward high contrast under harsh lighting. Slightly better than average exposure accuracy.

Outdoors, the Nikon D40 tended to lose highlight detail under harsh lighting. However, results are still pretty good overall, and the camera typically required less positive exposure compensation than we're accustomed to seeing on those of our shots that require it. Color is good and pretty bright, though just slightly warm and reddish.

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

ISO & Noise Performance
Low noise at the normal sensitivity settings, and surprisingly clean images at the higher settings.

The Nikon D40 produced low noise at its lower ISO settings, and even at ISO 800, image noise was quite acceptable. At ISOs 1,600 and 3,200, noise is higher, but the fine grain pattern and relatively low color (chroma) component of the noise helps minimize its effects. Pretty amazing, even ISO 3,200 shots look surprisingly good when printed. Excellent performance overall.

Extremes: Sunlit and low light tests
High resolution with good overall detail, but slightly high contrast under harsh lighting. Excellent low-light performance, capable of capturing bright, clean images under average city street lighting and in near darkness.

Sunlight:
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.)

The Nikon D40 produced slightly high contrast under the harsh lighting of the test above, even with its contrast level dialed down a bit in the Image Optimization menu. That said though, the lowest contrast setting lets the camera pretty well at holding onto detail in strong highlights. Some loss of detail due to noise suppression is visible in the shadows, though the remaining detail is still better than average there. The camera required less positive exposure compensation than average for this shot at +0.7 EV, which is good. (In "real life" though, be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible.) Overall color is good with the Auto white balance setting, if slightly reddish, with slightly pink skin tones. Very good results overall.

Low light:
The Nikon D40 captured bright images down to the darkest light level we test at (about 1/16 as bright as average city street lighting at night). The color looked good with the Auto white balance setting, and the camera's autofocus system was able to focus on the subject down to just above the 1/16 foot-candle light level, even without using the AF assist light. Do keep in mind though, that the very long shutter times necessary here absolutely demand the use of a tripod or other camera support to get sharp photos. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy.)

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.) For such applications, you may have better luck with a digital SLR camera, but even there, you'll likely need to set the focus manually.

Print Quality
Excellent print quality, great color, good 13x19 inch prints, tack-sharp 8x10s. ISO 1,600 images are amazingly clean, and even ISO 3,200 shots make surprisingly good 8x10s.

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 i9900 studio printer, and on the Canon iP5200 here in the office. (See the Canon i9900 review for details on that model.)

The Nikon D40's image quality belies its compact size and 6-megapixel imager. Prints as large as 13x19 inches are slightly soft when you squint at them from a few inches away, but look just great at normal viewing distances. Colors are bright and accurate, yet entirely believable.

The biggest challenge for print quality comes at high ISO settings, where image noise rears its head. This turned out to be an area where the Nikon D40 really shone, easily outdistancing any other camera we've seen in its price range to date, amazing us with its bright, clean images even at the most extreme ISO settings. At ISO 1,600, while there was some noise visible in 8x10 inch prints, it was really minimal, to the point that we think the vast majority of users would be happy to frame such prints and put them on their tables or walls. Even ISO 3,200 shots were surprisingly clean, so much so that we'd be inclined to use that setting for a lot of our own photos, intended for output as 8x10 inch prints. The D40's exceptional high-ISO performance demonstrates the advantage that cameras with lower megapixel ratings (and therefore larger individual pixels) can have over those that push for multiple megapixels at any cost. Even if you already own a "higher end" camera with more resolution, you might want to pick up a D40 as a handy little available-light shooter.

Bottom line, the Nikon D40 delivers really impressive print quality, particularly considering its price and size.