Sony NEX-6 Exposure
Sony NEX-6 Image Quality
Saturation & Hue Accuracy
Typical saturation levels and hue accuracy.
|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 to compare ISOs and click for larger versions.|
Saturation. The Sony NEX-6's overall default color saturation is oversaturated by 10.3% at base ISO, which is about average these days. Saturation remains fairly consistent across the ISO range, except at very high ISOs where it increases slightly. Reds and dark blues are boosted the most, but not as much as we often see. Most other colors are pushed just a bit, though yellow and cyan are slightly undersaturated which is quite common. Overall, saturation levels are quite pleasing to our eyes, and you can of course tweak them to your liking. 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 Sony NEX-6 does fairly well with Caucasian skin tones when white balance is adjusted to match the lighting. Brighter flesh tones have a healthy pinkish tint, though darker areas are nudged toward orange. Still, pretty 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. Like many cameras, the Sony NEX-6 pushes cyan toward blue, red toward orange, orange toward yellow and yellow toward green, but shifts are relatively minor. (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.) With an average "delta-C" color error of 5.23 after correction for saturation at base ISO, overall hue accuracy is about average, with accuracy only moderately lower at higher ISOs. Hue is "what color" the color is.
The Sony NEX-6 has a total of seven saturation settings available, three above and three below the default saturation. This covers a pretty wide range of saturation levels. Saturation also had little effect on contrast, which is how it should work.
|Saturation Adjustment Examples|
The table above shows results with five of the seven saturation settings, including the default and the two extremes. Click on any thumbnail above, then click again to see the full-sized image.
|See full set of test images with explanations
See thumbnails of all test and gallery images
Exposure and White Balance
Indoors, incandescent lighting
Warm casts with Auto and Incandescent, good with Manual, and a touch cool with Kelvin white balance settings. Average exposure compensation required.
|Auto White Balance
|Incandescent White Balance
|Manual White Balance
Indoors, under normal incandescent lighting, color balance is a bit too warm and orange with the Auto white balance setting, though results here are slightly better than average. Results with the Incandescent setting are a bit better but still somewhat warm and orange/yellow. The Manual setting is quite accurate, just slightly on the cool side. The 2,600 Kelvin setting which should match the color temperature of our lights is too cool and bluish. The Sony NEX-6 required +0.3 EV positive exposure compensation here, 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.)
Very good results under harsh lighting, with good handling of contrast, color, and exposure.
|Manual White Balance,
|Auto White Balance,
Outdoors, the Sony NEX-6 performed very well. +0.7 EV exposure compensation was required to keep the mannequin's face bright in our "Sunlit" Portrait shot, which is average among the cameras we've tested. (Actually, in fully automatic mode, exposure is bright without any compensation so the NEX-6 performs better than average here in full auto mode.) Contrast is a little high as you might expect under such harsh lighting, but the camera does a great job of holding onto detail in both the shadows and bright highlights, even without the help of DRO. We preferred Manual color balance for the "Portrait" shot though, as Auto white balance produced skintones that were a little too warm and yellow. Default exposure is quite good for our Far-field shot, with very few highlights blown again with DRO disabled. Only very dark shadows are a little noisy and posterized, but that's not usually an issue as we're talking *very* dark shadows. The Far-field shot with Auto white balance has very good color, just a touch cool. Overall, a very good performance in harsh lighting, especially considering DRO was off for these shots.
Very high resolution, ~ 2,200 lines of strong detail from JPEGs, up to 2,300 lines from raw files.
|Strong detail to
2,200 lines horizontal
|Strong detail to
2,200 lines vertical
|Strong detail to
2,300 lines horizontal
ACR converted RAW
|Strong detail to
2,200 lines vertical
ACR converted RAW
In-camera JPEGs of our laboratory resolution chart reveal sharp, distinct line patterns down to about 2,200 lines per picture height in both the horizontal and vertical directions. Some may argue for higher numbers, but aliasing artifacts start to interfere at this resolution. Complete extinction of the pattern doesn't occur until about 2,800 to 3,000 lines. Adobe Camera Raw was able to extract perhaps 100 lines more of resolution here from matching raw files, but the Sony NEX-6 does a good job holding on to high contrast detail at base ISO in its JPEGs. 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. The NEX-6 does seem to be a little prone to color moiré when using a sharp lens, though, as can be seen in the crops above and in some other test shots.
Sharpness & Detail
Good default sharpness, though fine detail is a little soft. Mild to moderate noise suppression visible in the shadows and areas of low contrast.
|Good definition of high-contrast
elements with some minor sharpening
artifacts. Fine detail is a little soft.
|Subtle detail: Hair
Noise suppression tends to blur
detail in areas of subtle contrast.
Sharpness. The Sony NEX-6 captures sharp, detailed images overall, though results are a touch soft at default settings, despite using the very sharp Carl Zeiss 24-70mm F/2.8 SSM lens at f/8 for the shot above left. There are some minor edge enhancement artifacts seen around high-contrast elements such as sharpening halos around the larger tree branches and pine cones, but they're not excessive and quite normal. Fine detail such as the smaller branches and pine needles show very little edge enhancement, but appear a little mushy. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.
Detail. The crop above right shows mild to moderate noise suppression in the darker areas of the model's hair. A number of low-contrast strands are smudged together, though higher contrast strands are still distinct. We saw similar results with fine detail in the pine needles being smudged. Still, pretty good results 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.
Aliasing Artifacts. As mentioned previously the Sony NEX-6 captures fairly sharp, detailed images, but it also seems a little more susceptible to moiré and other aliasing artifacts than most cameras when used with a sharp lens because of what appears to be a weak optical low pass filter.
As you can see in the crop on the right, color moiré is quite visible in the window shades of our Far Field shot. (Click on the crop to access the full resolution image.) We've also seen aliasing artifacts in some of our studio shots. We don't think it's a deal-breaker as quite a few cameras produce similar artifacts these days, but it is something to be aware of especially if you shoot a lot of man-made subjects with repeating patterns, such as buildings, fabrics, etc. Techniques than can be used to reduce or avoid false colors and moiré patterns include shooting at a smaller aperture so that lens diffraction acts as an anti-alias filter, defocusing slightly, shooting at higher ISOs, and post-processing particularly with raw files.
Raw vs In-Camera JPEGs
As noted above, the Sony NEX-6 produces in-camera JPEGs with very good detail, though fine, low-contrast detail is a touch soft. Quite a bit more detail can often be obtained from carefully processing raw files with a good converter, as can be seen below.
In the table above, mousing over a link at the bottom will load the corresponding crop in the area above, and clicking on the link will load the full resolution image. Examples include (from left to right): an in-camera Fine JPEG, the matching raw file processed through Sony's bundled Image Data Converter 4.2 software at default settings, another conversion processed with IDC's sharpening turned up to +50, and finally the same raw file converted with Adobe Camera Raw 7.3, then sharpened in Photoshop using unsharp mask at 300% with radius 0.3.
As you can see, the Sony IDC version at default settings is somewhat softer than the in-camera JPEG. Increasing the sharpening settings gave the image a crisper look, though noise reduction is still blurring fine detail. The Adobe Camera Raw conversion shows the most detail, but also reveals a bit more noise. You can always turn up the luminance noise reduction (default of zero was used here), or process the files in your favorite noise reduction program or plugin if you want cleaner images. Bottom line: as is usually the case, the Sony NEX-6 rewards raw shooters with better detail than JPEGs when processed with a good raw converter.
ISO & Noise Performance
Very good noise versus detail performance up to ISO 1,600.
Default High ISO Noise Reduction
|ISO 100||ISO 200||ISO 400|
|ISO 800||ISO 1,600||ISO 3,200|
|ISO 6,400||ISO 12,800||ISO 25,600|
The Sony NEX-6's JPEG images are quite clean at ISO 100 and 200, though as mentioned previously some very fine, mostly low-contrast detail is lost to noise reduction already at base ISO. There are demosaicing errors in the hair above the mannequin's forehead and color moiré in the jacket, though that's pretty common these days, especially with a sharp lens. ISO 400 is similar, with just a slight increase in smudging thanks to noise reduction. ISO 800 is slightly softer though detail is still very good, and the aliasing artifacts have practically vanished. ISO 1,600 appears progressively noisier as well as a bit softer, as you'd expect, but there's still lots of fine detail left and chroma noise is still not an issue. ISO 3,200 shows a larger hit to fine detail with stronger blurring, more visible luma noise as well as some minor chroma noise, though results here are still pretty good for the sensitivity. Image quality rapidly drops off at ISO 6,400 and above, with much stronger blurring and more noticeable luma noise accentuated by the camera's sharpening. Chroma noise is also stronger, but doesn't become too bad until ISO 25,600. Overall though, these are great results considering the class of the camera and the resolution offered. Our only real complaint is that the Sony NEX-6 doesn't offer much flexibility in noise reduction (only two levels: Normal and Low). As always, see the Print Quality section below for maximum recommended print sizes at each ISO.
A note about focus for this shot: We shoot this image at f/4, usually 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. We know this; 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. :-) The focus target position will 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 excellent highlight and shadow detail. Very good low-light performance, capable of capturing bright images in near darkness.
|+0.3 EV||+0.7 EV||1.0 EV|
Sunlight. The Sony NEX-6 handled the deliberately harsh lighting in the test above very well. We preferred the +0.7 EV exposure here, as the +0.3 EV exposure is a touch dim in the face while the +1.0 EV exposure is a bit too bright. Contrast is a little high, but shadow and highlight detail are both very good. Despite the bright appearance, few highlights were blown in the model's shirt and face at +0.7 EV, though the red channel is clipped in some of the flowers as is often the case, and in specular highlights where you'd expect clipping. Even fewer highlights were clipped with DRO enabled (see below). There are virtually no lost shadows, which is also very good, though very deep shadows are posterized. However, that's not really an issue except perhaps for those trying to recover a severely underexposed image.
For best results, be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible. See below for results with Dynamic Range Optimization and High Dynamic Range features enabled.
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.)
Dynamic Range Analysis
A key parameter in a digital camera is its Dynamic Range, the range of brightness that can be faithfully recorded. At the upper end of the tonal scale, dynamic range is dictated by the point at which the RGB data "saturates" at values of 255, 255, 255. At the lower end of the tonal scale, dynamic range is determined by the point at which there ceases to be any useful difference between adjacent tonal steps. Note the use of the qualifier "useful" in there: While it's tempting to evaluate dynamic range as the maximum number of tonal steps that can be discerned at all, that measure of dynamic range has very little relevance to real-world photography. What we care about as photographers is how much detail we can pull out of the shadows before image noise becomes too objectionable. This, of course, is a very subjective matter, and will vary with the application and even the subject matter in question. (Noise will be much more visible in subjects with large areas of flat tints and subtle shading than it would in subjects with strong, highly contrasting surface texture.)
What makes most sense then, is to specify useful dynamic range in terms of the point at which image noise reaches some agreed-upon threshold. To this end, Imatest computes a number of different dynamic range measurements, based on a variety of image noise thresholds. The noise thresholds are specified in terms of f-stops of equivalent luminance variation in the final image file, and dynamic range is computed for noise thresholds of 1.0 (low image quality), 0.5 (medium image quality), 0.25 (medium-high image quality) and 0.1 (high image quality). For most photographers and most applications, the noise thresholds of 0.5 and 0.25 f-stops are probably the most relevant to the production of acceptable-quality finished images, but many noise-sensitive shooters will insist on the 0.1 f-stop limit for their most critical work.
JPEG. The graph at right (click for a larger version) was generated using Imatest's dynamic range analysis for an in-camera Sony NEX-6 JPEG file with a nominally-exposed density step target (Stouffer 4110). At the base ISO of 100 (the optimal ISO) with DRO and HDR settings turned off, the graph shows 10.5 f-stops of total dynamic range, with 7.83 f-stops at the "High" Quality level. Roll-off at the highlight end of the curve is gradual, and the low end extends fairly linearly towards zero, but the steps get rather spread out, indicative of a tendency of the deepest shadows to break up into discrete levels (posterization) if you try to brighten them too much. These are are very good results, in the same ballpark as the best APS-C performers to date. Compared to its closest predecessor the NEX-5N, the NEX-6 scored slightly lower at the High Quality level (7.83 vs 8.02), but significantly higher in total dynamic range (10.5 vs 9.6 f-stops). Note though that this measurement has a margin of error of about 1/3 f-stop, so differences of less than 0.33 can be ignored.
Raw. The graph at right is from the same Stouffer 4110 stepchart image captured as a raw (.ARW) file, processed with Adobe Camera Raw using the Auto setting. (Slightly better results are likely possible with manually tweaking, but we weren't able to do much better.) As can be seen, the score at the highest quality increased by over two stops from 7.83 to 9.92 f-stops compared to the JPEG, while total dynamic range also increased more than two f-stops from 10.5 to 12.7. Again, these dynamic range scores are very good, and in the same ballpark as the best APS-C sensors at similar resolutions. Results here are essentially identical to the NEX-5N at the high quality level (9.92 vs 9.95 f-stops), though total dynamic range is slightly improved (12.7 vs 12.3 f-stops).
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 Sony NEX-6's contrast setting meets both challenges.
|Contrast set to lowest,
|Contrast set to lowest,
At its lowest contrast setting, the NEX-6 does a really excellent job of toning down highlights and opening up shadows while maintaining natural-looking skin tones. Very good results here.
|Contrast Adjustment Examples|
The table above shows five of the seven contrast setting, including the default and two extremes. It's pretty hard to evaluate small differences in contrast on small thumbnails like these, so click on any thumbnail to go to the full-size image.
One very nice feature of Sony'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. Sony did a good job here.
Dynamic Range Optimization is Sony's name for their dynamic range enhancement technology. DRO divides the image into small areas, analyzes the range of brightness of each area, and adjusts the camera's image processing parameters accordingly to make the best use of the available dynamic range. Auto DRO is enabled by default on the Sony NEX-6. You can also set the level manually, from 1 ("weak") to 5 ("strong"), or turn it off. As one would expect, DRO is only available for JPEG files.
The above thumbnails and histograms show the effects of the various levels of DRO on our "Sunlit" Portrait shot with +0.7 EV exposure compensation. Mouse over the links to load the associated thumbnail and histogram, and click on the links to visit the full resolution image. As you can see from the thumbnails and associated histograms, the Auto DRO setting did a good job boosting shadows and mid-tones without blowing additional highlights, and the five manual levels give quite a bit of control over the effect.
Above, you can see the effect of DRO settings on our Far-field shot. The default Auto setting produced a very good exposure overall, despite the harsh lighting. Nice.
High Dynamic Range. The Sony NEX-6's HDR mode takes three images in rapid succession, one nominally exposed , one underexposed, and one overexposed, then combines them into one high dynamic range JPEG automatically. Lighter areas from the underexposed image are combined in-camera with darker areas from the overexposed image to produce an image with compressed dynamic range. The camera then saves a single composite image, as well as the nominally exposed image. The overlaid images are micro-aligned by the camera, but it can only correct for so much movement. If it can't micro-align successfully, an icon indicating HDR capture failed will appear. For best results, the subject should not move or blink, so it's not really intended for portraits. There is also a manual mode where you can select 1 EV ("weak") to 6 EV ("strong") difference in exposures.
Mouse over the links to load the associated thumbnail and histogram, and click on the links to visit the full resolution image. As you can see, the Auto setting did a pretty good job, similar to the 4 EV manual setting. The higher the manual setting, the more highlights were toned-down and shadows opened up, but higher settings can produce flat and unnatural results with this scene.
Above, you can see the effect of HDR settings on our Far-field shot. Watch out for ghost images from subject movement during the capture sequence, though, as can be seen in some of the shots above.
Low Light. The Sony NEX-6 performed well in our low light test, producing bright images down to the lowest light level we test at (1/16 fc) at all ISO settings. Noise is very well controlled up to ISO 3,200, though as expected, at higher ISOs there are moderate to high amounts of fine luminance noise and some blotchy chroma noise. Auto white balance did a very good job here, producing a fairly neutral, just slightly cool color balance. A few hot pixels can be seen with long exposure noise reduction turned off (the right-most column), but nothing out of the ordinary. We didn't detect any significant banding or heat blooming issues, perhaps just a hint of horizontal banding at the highest ISO where it's not usual.
The camera's autofocus system was able to focus on the subject down to just above the 1/16 foot-candle light level unassisted with an f/2.8 lens, and the NEX-6 was able to focus in complete darkness with its built-in focus assist lamp enabled. Very good results.
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.) Thanks to their larger sensors, compact system cameras like the Sony NEX-6 tend to do better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects. (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.)
A terrific range of excellent printed images for the price. ISO 100 good at 24 x 36, but hung on a wall and viewed from 5 or 6 feet away, even 40 x 60s look fantastic! A good 13 x 19 inch print at ISO 1600, and a good 5 x 7 at ISO 12,800.
ISO 100 prints look quite good at 24 x 36, with 20 x 30s excellent - crisp detail and rich, vibrant colors. And as mentioned above, with the exception of minor softening and some slight pixilation in a few areas, these are suitable for wall display up to 40 x 60. Really remarkable for this class of camera.
ISO 200 is a carbon copy of ISO 100, with just the slightest softening in our target red swatch. Still quite good here at 24 x 36.
ISO 400 again shows only minor added softening in a few areas, but otherwise exceptional image quality. Detail and color are terrific at 20 x 30 with good wall prints possible up to 30 x 40.
ISO 800 16 x 20s look quite good here also, with 20 x 30s suitable for wall display.
ISO 1,600 shows more softening in some areas and luminance noise in the shadows, as is common at this ISO, but we'd still rate 16 x 20s as very good, and 20 x 30s fine for wall display.
ISO 3,200 produces very nice 13 x 19s and excellent 11 x 14 inch prints, again with only minor noise in the shadows and mild softening in a few areas.
ISO 6,400 11 x 14s would be suitable for most uses, and 8 x 10's look very good, with similar minor issues as mentioned above.
ISO 12,800 shots show a lot more blurring and blotchiness in many of the colored fabrics, but prints are good at 5 x 7.
ISO 25,600 prints are good at 4 x 6 and usable at 5 x 7.
For a camera at this price point to be capable of shooting images that print this well is amazing. Please remember, however, that we shoot these tests with our sharp reference lens and not the supplied kit lens, so your own results with a kit lens may vary somewhat. But the body of this camera is certainly capable of producing superb printed images for the price.
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 Mark II studio printer, and the Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha NEX-6 Photo Gallery .
Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Sony Alpha NEX-6 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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