Nikon Df Exposure

Saturation & Hue Accuracy
Realistic saturation and accurate colors.

Saturation. The Nikon Df pushes dark blues and some darker greens moderately, but actually undersaturates yellow, light green and cyan tones slightly. Overall, saturation levels are quite accurate, only 3.4% oversaturated at ISO 100, which is noticeably lower than most cameras. The Df's default saturation is quite consistent at low to moderately high ISOs, but increases to 110% at 204,800. Some may find the Df's default saturation too realistic and lacking "pop", but you can always adjust saturation and/or select the Vivid Picture Control. 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 Df's Caucasian skin tones looked realistic in outdoor lighting using auto white balance, just slightly on the pale side. (Likely because the camera doesn't pump reds as much as most.) Manual white balance produced slightly pinker results. 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 Df produces a few small color shifts relative to the mathematically precise translation of colors in its subjects, but its overall color accuracy is very good. Reds are shifted slightly toward orange, and cyan toward blue, but there are only slight shifts in orange, green and purple. (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.) Mean "delta-C" color error at base ISO was 4.53 after correction for saturation, which is quite good and better than average, and accuracy remained very good except at the highest ISO. Hue is "what color" the color is.

Saturation Adjustment
The Nikon Df lets you adjust image saturation and contrast in seven steps each, brightness in three steps, hue in seven steps and sharpening in ten steps. There are also Auto settings for saturation, contrast and sharpening. As can be seen below, the saturation adjustment worked very well, providing a reasonably fine-grained adjustment over a useful range of control. The saturation adjustment also has almost no impact on contrast. That's how a saturation control should work, but we've often found interactions between saturation adjustments and image contrast (and vice versa) on the cameras we test.

The series of shots above shows results with several different saturation adjustment settings, showing the minimum step size around the default, as well as both extremes. See the Thumbnails index page for more (look for the files named DFOUTBSATx.JPG). Click on any thumbnail above to see the full-sized image.

Exposure and White Balance

Indoors, incandescent lighting
Very warm results with Auto and Incandescent white balance, though excellent color balance with Manual and 2,600 Kelvin settings.

Indoors, in common incandescent lighting, color balance was very warm and reddish with the Auto white balance setting. (We'd say unacceptably so.) The Incandescent setting was also too warm and yellowish for our tastes. (Some users may prefer this look, though, as being more representative of the original lighting.) The Manual white balance setting produced accurate results, as did the 2,600 Kelvin color temperature setting (which matches the temperature of our lights in this scene). We can't really comment on exposure accuracy, as the Nikon Df doesn't play nicely with our third-party Sigma 70mm reference prime when it comes to exposure (see below). 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 for most major platforms. For some reason, though, on some (but not all) Nikon bodies, the Sigma causes the camera's exposure system to overexpose by somewhere between one third of a stop and a full stop depending on the aperture. The Df is one such body (as was the D4, D7000, D90 and D300S), as the exposure compensation settings actually used in the images above are lower than normal for this shot, while others are higher. Other than exposure shifts, 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 color and exposure outdoors, but somewhat high default contrast. Options like Active D-Lighting and contrast adjustment are a help when faced with tough conditions like these.

The Nikon Df handled tough outdoor lighting under harsh sunlight well. We found skin tones a touch pale in our "Sunlit" Portrait shot with Auto white balance though, so we preferred Manual WB. Default contrast was on the high side (as most users prefer), so a few highlights were clipped in the mannequin's shirt, pendant and some of the flowers while darker shadows were quite deep, though deep shadow noise is quite clean if a little yellow/green and posterized in this shot. We can't really comment on exposure accuracy for our "Sunlit" Portrait shot because of the Sigma lens compatibility issue (even the white balance setting affected exposure here). The Far-field image on the right was shot with the bundled Nikkor 50mm and was just slightly overexposed with a few clipped highlights in white areas. Again, detail in the shadows is very good, and deep shadow noise is low but a bit posterized. Color is both pleasing and realistic.

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

Resolution
Very high resolution, ~2,000 to 2,100 lines of strong detail from JPEGs, about 2,200 lines from converted RAW files.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 2,000 lines per picture height in the horizontal direction, and about 2,100 lines per picture height in the vertical direction in JPEGs. (Some might argue for higher, but aliasing artifacts begin to appear at those resolutions.) Complete extinction of the pattern didn't occur until around 2,800 to 3,000 lines. We were able to extract a bit more resolution with RAW files processed through Adobe Camera Raw 8.3, perhaps 200 lines horizontally and 100 vertically, while complete extinction was extended past 3,200 lines in both directions. The ACR conversion contained more color moiré than the in-camera JPEG images so the camera's processing is doing a pretty good job suppressing it. 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.

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

Sharpness & Detail
Very good detail for the resolution, though default sharpening is a bit higher than the D4. Minimal noise suppression artifacts at base ISO.

Sharpness. The Nikon Df produced sharp, detailed images for a 16-megapixel sensor at default settings, though we noticed edge enhancement artifacts are slightly more visible compared to the D4 around high-contrast subjects such as the sharpening halos around the lines and lettering in the crop above left. Overall, though, default sharpening is very good leading to crisper looking images while not being too oversharpened. (And you can always adjust sharpening to your liking.) 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 model's hair show a lot of detail. 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. The hair is also virtually free from chroma noise, which is often not the case. All in all, an excellent performance for the resolution 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.

RAW vs In-Camera JPEGs
As noted above, the Nikon Df does a great 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. Let's have a look at base ISO:

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 8.3 using default noise reduction with some strong but tight unsharp mask sharpening applied in Photoshop (250%, radius of 0.3 pixels, and a threshold of 0).

As is frequently the case, the demosaicing in Adobe Camera Raw and sharpening in Photoshop deliver finer detail than the camera, with fewer sharpening artifacts. Looking very closely at the images, ACR extracts a bit more detail that wasn't present in the JPEGs from the camera itself even in the red-leaf swatch Nikons do very well with. The ACR conversion manages to resolve some of the thread patterns in the fabrics while the camera treats them as noise and blurs them away. While they don't look quite as detailed, Nikon's rendering is smoother-looking and if you look very closely, there's less visible noise, though noise is by no means an issue with the Df. Still, we'd personally go the Adobe (or other high-quality third-party RAW converter) route here if we were concerned about making the sharpest-looking print possible from the Df's files. That said, the Df's in-camera JPEGs are excellent and you can always try adjusting image processing settings to your tastes.

ISO & Noise Performance
Excellent handling of noise vs detail to ISO 3200, with good performance up to ISO 12,800.

The Nikon Df's JPEG noise performance is similar to its big brother, the D4 with slightly lower chroma noise along with slightly higher luminance noise which is likely just the result of higher default sharpening.

Images are very clean at ISOs 50 through 800, which just a touch of luminance noise becoming more visible in the shadows as ISO increases. Performance at ISOs 1600 and 3200 is very good, with excellent detail retention despite slightly higher noise levels. Detail is still very good at ISO 6400, with a tight film-like noise "grain" and very little fine detail lost to noise reduction, though chroma noise is more noticeable. At ISO 12,800, subject detail is still quite good, much better than average at such a high ISO. ISO 25,600 is noticeably less detailed than lower sensitivity levels, with more visible noise reduction artifacts, though still usable. ISO 51,200 and above show a lot more chroma noise, in the form of yellow and purple blotches which also shifts white balance towards yellow. Some horizontal banding is also noticeable at ISO 51,200 and up, and ISO 204,800 shows a very strong blue shift in the shadows. Still, amazing high ISO performance, once of the best we've seen thanks to the Df's larger than average photosites and excellent image processing.

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.

A note about focus for this shot: We shoot this image at f/4, using one of three very sharp reference lenses (70mm Sigma f/2.8 macro for most cameras, 60mm f/2.8 Nikkor macro for Nikon bodies without a drive motor, and Olympus Zuiko 50mm f/2.0 for Four Thirds and Micro Four Thirds bodies). To insure that the hair detail we use for making critical judgements about camera noise processing and detail rendering is in sharp focus at the relatively wide aperture we're shooting at, the focus target at the center of the scene is on a movable stand. This lets us compensate for front- or back-focus by different camera bodies, even those that lack micro-focus adjustments. This does mean, though, that the focus target itself may appear soft or slightly out of focus for bodies that front- or back-focused with the reference lens. If you click to view the full-size image for one of these shots and notice that the focus target is fuzzy, you don't need to email and tell us about it; we already know it. :-) The focus target position will simply have been adjusted to insure that the rest of the scene is focused properly.

Extremes: Sunlit, dynamic range and low light tests
Very high resolution with very good highlight and shadow detail. Very good low-light performance, capable of capturing bright images in near darkness.

Sunlight:
The Nikon Df handled the deliberately harsh lighting well in the above test. Though contrast is a little high, highlight and shadow detail are very good. The "+0.3 EV" exposure did the best job here, though the mannequin's eyes are a bit dim. Relatively few highlights were blown in the mannequins's shirt and flowers at +0.3 EV, though there are some very dark shadows. Shadows are quite clean, but very deep shadows tend to have a green/yellow tint. Note that these shots were captured with the Nikon Df's Active D-Lighting control set to its default of "Off." See below for how Active D-Lighting and contrast settings help with hot highlights and deep 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.)

Contrast Adjustment
We really like it when a camera gives us the ability to adjust contrast and saturation to our liking. It's even better when those adjustments cover a useful range, in steps small enough to allow for precise tweaks. Just as with its saturation adjustment, the Nikon Df's contrast setting meets both challenges, the contrast steps actually being a little finer than those for saturation, and thus even more to our liking.

At its lowest contrast setting, the Df did a good job of preserving highlight detail, maintaining natural-looking skin tones, and bringing nice detail out of the shadows. Overall, very good results here, especially when the contrast setting is tweaked. (This is a really tough shot; the Nikon Df does a better than average job handling it.)

The series of shots above shows results with several different contrast adjustment settings, showing the minimum step size around the default, as well as both extremes. While you can see the extremes, it's hard to really evaluate contrast on small thumbnails like these, click on any thumbnail to go to the full-size image.

One very nice feature of Nikon's contrast adjustment is that it has very little effect on color saturation. Contrast and saturation are actually fairly closely coupled, it's a good trick to be able to vary one with out the other changing as well. As usual, Nikon did a good job here.

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 1, Extra High 2 and Auto) available on the Nikon Df 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.)

Mouse over the links to see how the various levels of Active D-Lighting affects our "Sunlit" Portrait shot at default exposure. Click on a 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, the various Active D-Lighting settings did a very good job at preserving highlights while bringing up shadows and deeper midtones, without making the image look too flat. Normally, there is a noise penalty to be paid for boosting shadows, but noise levels in the shadows are very low with this sensor, so increased shadow noise is not much of a concern here. It's also interesting to note that the default ADL setting for the Df is Off, while in more consumer-oriented models, the default is Auto.

See below for how Active D-Lighting worked with our Far-field shot.

Here are the results with our Far-field shot. As you can see, Active D-Lighting brought up shadow detail while holding on to highlights. Also note the slight blue cast in the white pillars and trim of the building as the strength of Active D-Lighting is increased. The Auto setting did a pretty good job here.

HDR Mode
Like other recent Nikon DSLRs, the Df offers an in-camera high-dynamic-range imaging function. When enabled, the Df 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.

Mouse over the links to see how the various levels of HDR with default smoothing affects our Far-field shot at default exposure. Click on a link to get to the full-res image.

Because the Nikon Df performs micro-alignment of the two images, the resulting field of view is slightly cropped. The system can only correct for small amounts of camera movement between shots, though, so Nikon recommends the use of a tripod. Obviously moving subjects should also be avoided, as you can see from the ghosting around people, branches and flags in the HDR shots above. Overall, we think Nikon Df's in-camera HDR is one of the better implementations.

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.

Since the Nikon Df has virtually identical dynamic range test results as the D4, we decided to compare it to some other "compact" full-frame models: the Canon 5D Mark III and Sony A7. As you can see from the above graph (click for a larger image), the Df's dynamic range is about a stop less than the A7's at the ISO 100 setting (13.09 EV vs 14.01), but it soon catches up and indeed surpasses the A7 above ISO 400. The Df's dynamic range is however more than a full stop better than the 5D Mark III's at lower ISOs, though at moderate to high ISOs, it's only slightly better. Keep in mind these are resolution-normalized results, so the Nikon Df's lower resolution puts it at a slight disadvantage compared to "screen" dynamic range. Click here to visit the DxOMark page for the Nikon Df for more of their test results and additional comparisons.

Low Light. The Nikon Df performed well here, able to capture usable images down to the 1/16 foot-candle light level (about 1/16 as bright as average city street lighting at night) at all ISO settings, though lower light levels at ISO 50 are a bit dim because of the 30 second shutter speed limit (Bulb mode is required for longer exposures).

Color balance with Auto white balance is fairly neutral at higher light levels, but took on an increasingly stronger magenta cast as light levels dropped and ISO increased, as we've seen with other Nikons.

Noise is quite low up to ISO 12,800, and even at higher ISOs there's still a lot of detail to work with, especially when high ISO NR is set to "Off" (which still applies some noise filtering at ISO 3200 and above). The Nikon Df gives you four options for high ISO noise reduction: Off, Low, Normal, and High, so you have some flexibility in deciding how much noise to trade for detail. Except for the "No NR" shots in the table above, these were all shot using the Normal NR setting, and Long Exposure NR was enabled so it was applied to exposures longer than one second.

Some horizontal banding (pattern noise) is visible at ISO 25,600 and above, and there's also a purple tint emanating from the bottom right at very high ISOs indicating some heat blooming, likely from a warm component nearby. Longer exposures at lower ISOs may show similar heat-blooming discoloration.

We did notice some hot pixels, one of which is visible even in our brightly-lit Still Life studio images as well as in some other shots at ISO 1600 and 3200, however the offending pixel(s) can easily be mapped out. While the Df does not have a pixel remapping menu option that some other manufacturers provide, we've heard running sensor cleaning twice in a row on recent Nikon DSLRs will also remap bad pixels, so we gave it a try. Sure enough, it worked! So if you spot hot pixels from your Nikon DSLR, try this apparently undocumented feature. It just may save you a trip to a Nikon service center!

The camera's phase-detection autofocus system was able to focus on our test subject down to just below the 1/8 foot-candle light level unassisted with an f/2.8 lens, which while good, isn't quite as good as expected for this class of camera. The Nikon Df doesn't have a built-in AF illuminator, but can utilize the illuminator found on most compatible flash units. In Live View mode, the Df's contrast-detect autofocus was able to focus down to just above the 1/16 foot-candle, which is very good.

(Keep in mind that the longer shutter speeds here demand the use of a tripod to prevent any blurring from camera movement. 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.)

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 Df 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 up to ISO 200; a nice 16 x 20 at ISO 3200; a good 4 x 6 at ISO 51,200.

ISO 50 through 200 prints look excellent at 30 x 40 inches, with incredible detail for this size. Wall display prints look great even at 40 x 60 inches, with pixelation only appearing if you get close and squint.

ISO 400 also produces a good 30 x 40 inch print and is super sharp for this ISO and size. Wall display prints are quite good up to 36 x 48 inches.

ISO 800 yields a very good 24 x 36 inch print, an excellent size for ISO 800 and maintaining fine detail even in our tricky target red swatch (which Nikons do particularly well with) and revealing virtually no noise in flatter areas. One of the best ISO 800 prints we have yet seen from any camera, as well as a 20 x 30 inch print here with amazing clarity.

ISO 1600 images begin to show the first trace of minor chroma noise in flatter areas, but this ISO still produces a very nice 20 x 30 inch print and a super-tight 16 x 20.

ISO 3200 prints a good 16 x 20, with only a moderate amount of noise in flat and shadowy areas. Our target red swatch is still rendered with an amazing amount of detail, almost unprecedented for this ISO.

ISO 6400 produces a 13 x 19 inch print that is usable for less critical applications, and an 11 x 14 that is quite good.

ISO 12,800 yields a rarity in the print department for this ISO: a good 8 x 10 inch print!

ISO 25,600 prints a very good 5 x 7, yet again an amazing feat at this ISO.

ISO 51,200 allows for a good 4 x 6 inch print.

ISOs 102,400 and 204,800 do not yield good prints and are best avoided.

DxOMark awarded the Nikon Df its best low light score to date, and that is certainly supported from our results here. It is simply THE low light camera, doing a terrific job yielding good prints all the way to ISO 51,200. What is most amazing is the Df's capabilities in common low light settings of ISO 800 through ISO 6400, where very large prints for these settings are still possible, and a rare 8 x 10 inch print size is easily attainable at ISO 12,800!