Sony RX100 Image Quality
Saturation & Hue Accuracy
Realistic saturation levels, but with slightly below average hue accuracy.
Skin tones. Here, when adjusted for optimal white balance, the Sony RX100 did well, producing fairly natural-looking Caucasian 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 Sony RX100 pushed cyan toward blue, orange toward yellow, and yellow toward green by moderate amounts, but most other shifts were pretty 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, and we don't find the resulting color objectionable. The RX100's handling of yellows and yellow-orange colors is one of its real weaknesses: Yellows are rendered closer to a yellow-green, and significantly undersaturated as well. With a mean "delta-C" color error of 6.04 after correction for saturation, overall hue accuracy was a touch below average, but still well within acceptable limits. Hue is "what color" the color is.
The Sony RX100 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 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 images
Exposure and White Balance
Indoors, incandescent lighting
Auto setting produced warmest results, but Incandescent and Manual were also a bit too warm, while the 2,600 Kelvin setting was too cool. Average exposure compensation required.
|Auto White Balance
|Incandescent White Balance
|Manual White Balance
Indoors, under normal incandescent lighting, color balance was warm and orange with the Auto white balance setting. Results with the Incandescent setting were also warm, though not quite as warm as Auto. The Manual setting was the most accurate, but still warmer than we'd like. The 2,600 Kelvin setting which matches the color temperature of our lights resulted in a cool, slightly bluish image. The Sony RX100 required +0.3 EV positive exposure compensation here, which is about average. (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 RX100 performed well. +0.3 EV compensation was required to keep the model's face bright in our "Sunlit" Portrait shot. The average among the cameras we've tested is +0.7 EV, so the RX100 performed better than average here, especially considering Dynamic Range Optimization (DRO) was disabled for these shots which tends to brighten shadows. (More on DRO below.) Contrast is a little high, as you might expect under such harsh lighting, but the camera does an excellent job of holding onto detail in bright highlights and shadows, even without the help of DRO. Auto white balance rendered the model's face a touch too warm, though, so we preferred results from the Manual white balance setting. Colors are just a touch cool in our Far-field shot using Auto white balance, though still quite pleasant. Exposure is quite good with virtually no blown highlights, though some shadows are very deep.
Very high resolution, ~2,300 lines of strong detail from JPEGs.
|Strong detail to
~2,300 lines horizontal
|Strong detail to
~2,300 lines vertical
In camera JPEGs of our laboratory resolution chart revealed sharp, distinct line patterns down to about 2,300 lines per picture height in both the horizontal and vertical directions. Some may argue for more, but aliasing artifacts start to interfere at that point. Complete extinction of the pattern didn't occur until about 2,800 to 3,000 lines. 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 good detail and sharpness, though some sharpening artifacts are visible around high-contrast elements. Low to moderate levels of noise suppression visible in the shadows and areas of low contrast.
|Very good definition of high-contrast
elements with some visible
|Subtle detail: Hair
Noise suppression tends to blur
detail in areas of subtle contrast.
Sharpness. The Sony RX100 captures sharp, detailed images, though there are some mild to moderate edge enhancement artifacts on high-contrast elements such as the sharpening halos seen around the text in the crop above left. Still, pretty good results here. 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 good detail with low to moderate levels noise suppression in the darkest areas of the model's hair. Quite a few individual strands are smudged together in areas of low contrast at base ISO, but performance is actually quite good considering the size and resolution of the sensor. 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.
ISO & Noise Performance
Very good noise vs detail performance, with good results up to ISO 800.
Default High ISO Noise Reduction
|ISO 80||ISO 100||ISO 125|
|ISO 200||ISO 400||ISO 800|
|ISO 1,600||ISO 3,200||ISO 6,400|
As you'd expect, the Sony RX100's high-ISO performance isn't up to the level of the best APS-C sensor size SLRs, but it's head and shoulders above anything remotely approaching its diminutive size. The camera's high resolution means that the crops above are at a larger scale than those of many cameras you might compare it to, but there's no denying that cameras with larger sensors will beat it in the ISO sweepstakes.
When you compare to digicams that the RX100 competes with in the size category, though, there really is no comparison. Noise levels are a good two stops better than even high-end pocketable digicams.
Perhaps thanks to the very high sensor resolution, we see very few of the demosaicing errors we've come to expect in the hair above the mannequin's forehead, and little to no moiré in her jacket.
The camera holds onto good detail in the strong reds of the rose in the vase on the table up through ISO 400, and it softens gracefully from there on up. Detail in the difficult hair area decreases more or less steadily from base ISO on up, but it's a pretty graceful degradation, and the high pixel count means that parts that look rough on-screen at 1:1 print surprisingly well.
We find two things particularly appealing about the Sony RX100's high-ISO performance: There's virtually no chroma noise, and what luminance noise there is, is very fine-grained, making it much less obtrusive than it might otherwise be.
One negative we do note, though, is that color saturation does fall off pretty significantly at the really high ISO settings. This is a common tactic to keep noise under control, and the RX100 isn't as bad as some cameras in this regard, but it's pretty noticeable nonetheless.
As always, check the Print Quality section below for the final word on how the RX100's images appear in print. As you'll see there, the printed output is pretty impressive.
Extremes: Sunlit, dynamic range and low light tests
Very high resolution with good dynamic range for a compact. Very good low-light performance, capable of capturing bright images in near darkness. Special modes make it possible to capture low-light images without a tripod.
|0 EV||+0.3 EV||+0.7 EV|
Sunlight. The Sony RX100 handled the deliberately harsh lighting in the test above very well. It was a tough call between the 0 EV and +0.3 EV shot here. The mannequin's face is a little dim at the default exposure, so we'd probably go with the +0.3 exposure for everyday pictures. We used the 0 EV setting for our Contrast and DRO example series, though, because it did do the best job of holding onto the strong highlights in the mannequin's shirt.
Contrast is a little high, but highlight detail is excellent, and shadow detail pretty good. Despite the apparent brightness, there are actually almost no clipped highlights in the model's face and shirt at 0 EV, with just a little clipping occurring in specific color channels in the flowers (mostly in the red channel), or in specular highlights where you'd expect it. There were only a few shadows that were completely lost, but if you work too hard to pull up detail, the shadows break apart into discrete levels.
Of course it's best to use fill flash in situations like the one shown above, and better still to shoot in the shade when possible.
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 RX100 JPEG file with a nominally-exposed density step target (Stouffer 4110). At the base ISO of 125 (the optimal ISO) with DRO and HDR settings turned off, the graph shows 9.63 f-stops of total dynamic range, with 7.05 f-stops at the "High" Quality level. Roll-off at the highlight end of the curve was gradual, and at the low end extends pretty linearly towards zero, but the steps get rather spread out, indicative of a tendency of the deepest shadows to break up into discrete levels if you try to brighten them too much. These are are good numerical results, with the total range detected as good as that of the Sony NEX-5N, although the dynamic range at the best quality level fell somewhat short. Considering the much smaller sensor size of the RX100, this is a pretty impressive performance. 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 when comparing.
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. The Sony RX100's dynamic range scores from raw files are surprisingly good especially for a compact camera, matching and even besting some popular APS-C SLRs. Total dynamic range came in at 12.3 f-stops, a hugh improvement over the JPEG's 9.63 f-stops, and better than a quite a few SLRs and CSCs with much larger sensors. Dynamic range at the highest quality level also improved though less dramatically, from 7.05 to 7.51 f-stops. That's not as good as most recent SLRs and CSCs, limited by the RX100's higher noise levels generated by its smaller photosites. Still, this is a remarkable performance from a compact camera. As always, it's worth noting here is that ACR's default noise reduction settings reduced overall noise somewhat (see the plot in the lower left-hand corner) relative to the levels in the in-camera JPEG, which would tend to boost the dynamic range numbers for the High Quality threshold. Also, the extreme highlight recovery being performed by ACR here would likely produce color errors in strong highlights of natural subjects.
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 RX100's contrast setting meets both challenges.
At its lowest contrast setting, the RX100 did a really excellent job of preserving highlight detail, maintaining natural-looking skin tones, and holding reasonable detail in the shadows. Overall, 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.
Outdoor Portrait DRO Comparison
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 RX100. 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 no 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, DRO had only a slight effect on the highlights in this shot, though few highlights were clipped to begin with at default. The bulk of the difference between different levels of DRO is found in the shadows and darker midtones. The stronger the DRO level, the more boost is applied to darker areas. That usually results in more visible noise in boosted areas of the image, but the RX100 produces images with reasonably low shadow noise for its class, so increased noise wasn't really an issue even at the highest DRO levels.
High Dynamic Range. The Sony RX100 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 increased dynamic range. 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 be static or there could be "ghost" images, though the RX100 seems to do a good job at avoiding them. There is also a manual mode where you can select 1 EV ("weak") to 6 EV ("strong") difference in exposures.
Mouse over the above links to load the associated thumbnail, and click on the links to visit the full resolution image. As you can see the effect can be quite subtle with no difference between some of the settings, however the Auto setting did a pretty good job at boosting shadows, reducing highlights, while still retaining enough contrast.
Low Light. The Sony RX100 performed well in our low light tests, producing bright images down to the lowest light level we test at (1/16 fc) at all ISO settings. Noise is remarkably well-controlled, with essentially zero chroma noise, and very fine-grained luminance noise that is surprisingly unobtrusive. Even the shots with noise reduction disabled are very appealing, even at the highest ISO settings and lowest light levels. We didn't see any significant issues with uncorrected hot pixels or banding.
Auto white balance did a very good job here, producing a fairly neutral, just slightly cool color balance at all ISOs and light levels, though darker colors were a bit cooler than lighter ones. We also saw little to no evidence of banding, even at ISO 6,400, and at least at first inspection, no sign of hot pixels either.
The camera's autofocus system was able to focus on the subject down to the lowest light level shown here (about 4 stops down from typical city street lighting at night), and it can focus in complete darkness with its built-in focus assist lamp enabled. We found, though, that if your subject is close, the assist lamp may actually be too bright, overwhelming the autofocus system. You can always turn it off if that's an issue.
(All shots taken at 1/16 foot-candle)
Crazy Low Light. In common with their SLR and CSC models, the Sony RX100 goes even further for low-light shooting, taking advantage of its fast multi-shot capability to boost ISO and reduce noise even further. It does this by grabbing multiple shots of a subject in rapid succession, and then micro-aligning and adding or "stacking" them together to produce the final image. The results are shots built from shorter individual exposures that are easy to hand-hold, and significantly reduced noise as a result of the summing procedure. The thumbnails in the table above link to examples of this, captured in the camera's Multi-frame Noise Reduction mode.
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 RX100 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.)
Outputs 24 x 36-inch prints from ISO 80 to 200; ISO 1,600 shots look great at 11 x 14; and even ISO 6,400 prints make a good 5 x 7.
Though its official base ISO starts at 125, the Sony RX100's ISO 80 images looked good printed at 24 x 36 inches. Color was muted, particularly yellows and greens, as we also found in our MacBeth test target.
ISO 125 shots also looked quite good at 24 x 36, with excellent detail, but the muted color persisted.
ISO 200 images also looked very good at 24 x 36, if a little softer than ISO 125. Not enough to require a smaller print size.
ISO 400 images printed very nicely at 20 x 30 inches, with sharp detail.
ISO 800 shots were soft enough at 20 x 30 that we preferred the 16 x 20-inch prints, though we'd still call the 20 x 30-inch prints usable for most subjects. By ISO 800, the red leaf swatch appeared soft.
ISO 1,600 shots are usable at 13 x 19 inches, but look better at a still fairly large 11 x 14 inch size. The red leaf swatch was somewhat soft at this point.
ISO 3,200 images look good at 8 x 10 inches, with the exception of the difficult red leaf swatch.
ISO 6,400 images are a bit soft for 8 x 10 inch prints, but look quite good at 5 x 7 inches.
Overall, the Sony RX100 stands out as a pocket camera that can produce good quality 24 x 36 inch prints from ISO 80 to 200, and even its highest ISO of 6,400 outputs a good quality 5 x 7. Impressive!
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.)