Sony A5100 Exposure

Saturation & Hue Accuracy
Typical saturation levels and hue accuracy.

Saturation. The Sony A5100's overall default color saturation is oversaturated by 9.9% at base ISO, which is about average these days. Mean saturation gradually falls off as ISO is increased up to ISO 12,800, where it drops more rapidly to 102.8%, ending up at only 98.3% at ISO 25,600. Reds and dark blues are boosted the most, but not as much as we often see. Most other colors are pushed just a bit or pretty close to ideal, though yellow, light green and cyan are slightly undersaturated. Overall, saturation levels are pleasing to our eyes at low to moderate ISOs, and you can of course tweak them more 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 A5100 does fairly well with Caucasian skin tones when using Manual white balance in simulated daylight. Brighter flesh tones have a healthy pinkish tint, though darker areas are nudged toward orange. With Auto white balance, results are still good, though slightly warmer. 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 A5100 shifts cyan toward blue, red toward orange, orange toward yellow and yellow toward green, however shifts are minor to fairly moderate. (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 5.59 after correction for saturation at base ISO, overall hue accuracy is about average, with only minor fluctuations across the ISO range. Hue is "what color" the color is.

Exposure and White Balance

Indoors, incandescent lighting
Warm cast with Auto, but good color with Incandescent and Manual. Average exposure compensation required.

Indoors, under normal incandescent lighting, color balance is too warm and orange with the Auto white balance setting. Results with the Incandescent setting are better but still a touch warm and yellow. The Manual setting is quite accurate, just slightly on the cool side. The Sony A5100 required +0.3 EV positive exposure compensation here, about average for this shot, though the images are a bit on the bright side (while zero exposure compensation is a touch dim). (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
Very good results under harsh lighting, with good handling of contrast, color, along with above average exposure accuracy.

Outdoors, the Sony A5100 performed very well. +0.3 EV exposure compensation was required to keep the mannequin's face bright in our "Sunlit" Portrait shot, which is better than average among the cameras we've tested. (Most cameras require about +0.7 EV here.) Contrast is a little high as you might expect under such harsh lighting, but despite the bright appearance, only a few highlights were blown, even without the help of Dynamic Range Optimization (DRO -- see below). There are some dark shadows, but shadow detail is quite good and noise is fairly low except in very deep shadows. Both Auto and Manual white balance produced decent skin tones, but we preferred Manual for its slightly pinker response. Default exposure is quite good for our Far-field shot (above right), just a touch underexposed but with almost no highlights blown (just specular highlights) or shadows lost, again with DRO disabled. The Far-field shot with Auto white balance has very good color, just a touch on the cool side. Overall, a very good performance in harsh lighting, especially considering DRO was off for these shots.

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

Resolution
Very high resolution, ~2,800 to ~2,900 lines of strong detail from both JPEGs and RAW files.

In-camera JPEGs of our laboratory resolution chart reveal sharp, distinct line patterns down to about 2,900 lines per picture height in the horizontal direction, and to about 2,800 lines in the vertical direction. Some may argue for higher numbers, but aliasing artifacts and false colors start to interfere at these resolutions. Complete extinction of the pattern doesn't occur until about 3,500 to 3,600 lines. Some color moiré is evident in JPEGs, though that's not uncommon. Adobe Camera Raw wasn't really able to extract more lines of resolution here from a matching RAW file, and it generated stronger color moiré (different colors as well), so the Sony A5100 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.

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

Sharpness & Detail
Very good default sharpness, with only minor sharpening artifacts. Mild to moderate noise suppression visible in the shadows and areas of low contrast.

Sharpness. The Sony A5100 captures fairly sharp, crisp images at lower ISOs, with few visible edge enhancement artifacts. We often see some fairly bright or thick sharpening halos around high-contrast elements such as the lettering and lines in our bottle labels, but the A5100's default sharpening is very good at making details pop without obvious sharpening artifacts. Very good results here, at least at low ISO. 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 mannequin's hair. A number of low-contrast strands are smudged together, though higher contrast strands are still distinct. Overall, pretty good results here especially for a 24-megapixel APS-C sensor, though noise reduction takes its toll on fine low-contrast detail. 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 Sony A5100 produces in-camera JPEGs with very good detail and few sharpening artifacts, at least at low ISOs. Additional detail can often be obtained from carefully processing RAW files with a good converter, though. Let's see how base ISO compares here:

In the table above, we compare a best quality 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 8.7 beta using default noise reduction with some strong but tight unsharp masking applied in Photoshop (250%, radius of 0.3 pixels, and a threshold of 0).

Looking closely at the images, we cam see that ACR extracts additional detail that isn't present in the JPEG from the camera, particularly in the red-leaf swatch where the fine thread pattern is likely treated as noise by the JPEG engine. Fine detail in the mosaic is also slightly improved, but as is often the case, more noise can be seen in the bottle crop. You can of course apply stronger noise reduction (default ACR NR used here) to arrive at your ideal noise versus detail tradeoff. That being said, the Sony A5100's in-camera JPEG processing (at least at low ISOs) is pretty good with generally excellent detail and very few sharpening artifacts, though default noise reduction is a touch heavy-handed particularly in the red fabric here.

ISO & Noise Performance
Good detail versus noise tradeoff up to about ISO 1600.

The Sony A5100's JPEG images are similar to the A6000's, but with slightly stronger default noise reduction and slightly lighter sharpening, yielding images that don't look quite as "processed" as the A6000's, but also a little less crisp.

Image quality is excellent at ISOs 100 through 400, with only a slight drop in fine detail at 400 where stronger noise reduction kicks in. ISO 800 is quite good, just a touch softer, as is ISO 1600. ISO 3200 has a fair amount of detail intact, but flatter areas start to take on a hammered look noise is more visible. Fine detail rapidly deteriorates from ISO 6400 on, especially in the red channel, while chroma blotches and noise reduction artifacts become obtrusive at ISO 12,800 and above.

Overall, though, these are very good results especially considering the A5100's size, resolution and price point, though advanced users will likely turn to RAW capture for best results at higher ISOs. As always, see the Print Quality section below for maximum recommended print sizes at each ISO, as printed performance often doesn't correlate well to what's seen on-screen at 100%, and check out our Comparometer to see how the Sony A5100's JPEGs compare to other cameras we've tested.

A note about focus for this shot: We shoot this image at f/4, usually using one of our very sharp reference lenses. 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.

Sunlight. The Sony A5100 handled the deliberately harsh lighting in the test above very well. We preferred the +0.3 EV exposure here as the face is bright while only a few highlights were clipped in the white shirt. The default (0 EV) exposure is just a tad dim in the face, while the +0.7 EV exposure is definitely too bright. As mentioned previously, contrast is a little high, but both highlight and shadow detail is very good at +0.3 EV.

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 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 tone curve and other processing parameters accordingly to make the best use of the available dynamic range. DRO does not boost ISO for the entire image like some systems, so increased noise is less of an issue, though existing noise may be more visible in raised shadows. Auto DRO is enabled by default on the Sony A5100. You can also set the level manually, from 1 ("weak") to 5 ("strong"), or turn it off. As one would expect, DRO is only applied to JPEG files however RAW files are tagged for similar processing by Sony's IDC software.

The above thumbnails and histograms show the effects of the available 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 histograms, DRO worked as expected, boosting shadows and mid-tones without blowing additional highlights, yielding more balance exposures. The Auto DRO setting did a good job here, and the five manual levels give quite a bit of control over the effect.

Above, you can see the effects of DRO settings on our Far-field shot. The default Auto setting produced a nicely balanced exposure, despite the harsh lighting. A useful feature.

High Dynamic Range. The Sony A5100'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 (RAW images are not supported). Lighter areas from the underexposed image are combined with darker areas from the overexposed image to produce an image with compressed tonal 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 decent job boosting shadows and mid-tones while reigning back highlights, however we prefer the lower manual settings for this subject. The higher the manual setting, the more highlights are toned-down and shadows opened up, but higher settings can produce flat and unnatural results with this scene. Still, it's nice that Sony provides six manual levels, giving quite a bit of control over the effect.

Above, you can see the effects of HDR settings on our Far-field shot. Watch out for ghost images from movement within the scene during the capture sequence, though, as can be seen in some of the shots above. Still, a useful feature, and Sony has one of the better in-camera HDR implementations we've seen.

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.

Here, we decided to compare the Sony A5100's dynamic range to its more expensive sibling, the A6000, and also to the 16-megapixel Olympus E-M10, a similarly-priced Micro Four Thirds camera with a top performing 4/3" sensor. You can always compare other models on DxOMark.com.

As you can see from the above graph (click for a larger image), at base ISO the Sony A5100's dynamic range scored a little lower than the A6000 (12.7 vs 13.1 EV), however that difference is likely close to the margin of error for the test, and the two Sonys performed practically identically at other ISOs. The Sony A5100 does a little better than the Olympus E-M10 at most ISOs: At base ISO, the E-M10 manages 12.3 vs the A5100's 12.7, then the scores converge at around the ISO 200 mark, but the Sony starts to pull away as sensitivity increases, with up to about a one stop advantage at ISO 12,800.

Overall, good dynamic range performance from the Sony A5100 though some other APS-C cameras do better (the Nikon D5300 DSLR for example scored 13.9 EV at base ISO). Click here to visit the DxOMark page for the Sony A5100 for more of their test results and additional comparisons.

Low Light. The Sony A5100 was able to capture bright images down to the lowest light level we test at (1/16 fc) even at base ISO. Noise is very low at base ISO and well-controlled at ISO 3200, though as expected, but noise and noise reduction artifacts are quite high and objectional at the highest ISO setting of 25,600.

Auto white balance did a very good job here, producing a fairly neutral, just slightly cool color balance across ISOs and light levels.

We didn't detect any significant banding (pattern noise), heat blooming or hot pixel issues.

The Sony A5100's autofocus system was able to focus on our test subject down to the 1/8 foot-candle light level unassisted with an f/2.8 lens, which is good. And the A5100 was able to focus in complete darkness with its built-in focus assist lamp enabled (with the subject in range).

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 pixels and in the case of the A5100, its Hybrid AF system, compact system cameras like the Sony A5100 tend to do much 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.)

Coverage and Range
A weak flash with very narrow and uneven coverage at wide angle. Our standard indoor portrait shot required more than average exposure compensation and still came out dim.

Coverage. Flash coverage is very narrow and uneven at wide angle (16mm), leaving very dark corners in our flash coverage test image. We no longer test at full telephoto is coverage is invariably better, making wide angle the worst case.

Exposure. Our Indoor Portrait test scene came out dim even with +1.0 EV flash exposure compensation at ISO 200, and flash exposure compensation didn't make much difference. The average amount of flash exposure compensation required for this scene is +0.7 EV, so the A5100's built-in flash performed below average here, and there's no hot shoe to connect a more powerful flash. The camera's Slow-Sync flash mode produced very bright results with no flash exposure compensation, though with a strong orange cast from the ambient room lighting.

Manufacturer Specified Flash Test. The Sony A5100's built-in flash is rated with a Guide Number of 4 meters or 13.1 feet at ISO 100. At ISO 200, that works out to about 3.3 feet at f/5.6, the maximum aperture of the kit zoom lens at full telephoto. In the test shot above taken at the aforementioned distance and settings, the A5100's flash produced a bright flash exposure, which confirms Sony's rather weak flash power rating is at least credible.

Our standard test method for flash range uses a fixed setting of ISO 200, to provide a fair basis of comparison between cameras. We also shoot two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.

Print Quality

Excellent 30 x 40 inch prints at ISO 100/200; a nice 16 x 20 at ISO 1600; and even prints a usable 4 x 6 at ISO 25,600.

ISO 100/200 produces an excellent 30 x 40 inch print and higher -- able to print virtually as high as the resolution allows until pixelation is visible.

ISO 400 yields very good 24 x 36 inch prints, although 30 x 40's are more than suitable for wall-display purposes with minimal noise in only a few flatter areas.

ISO 800 prints are quite good at 16 x 20 inches, which is a very usable size for this ISO and yet again only minimal noise visible in a few areas of the test image.

ISO 1600 also delivers a good 16 x 20 inch print. Detail in the red fabric swatch of our test target is beginning to be lost, which is typical of most cameras by this point on the ISO ladder. There is also a touch of noise in flatter, shadowy areas of our test target, but still an amazing feat for this ISO and fairly uncommon for this price bracket.

ISO 3200 yields a good 13 x 19 inch print which is mostly free from noise in most areas other than a few flatter regions of our target, although our red swatch is showing less and less detail.

ISO 6400 delivers a usable 8 x 10 inch print, which is not bad for this ISO. We'd hoped the 11 x 14 would turn out as good as the 13 x 19 inch print at ISO 3200, but there is just a bit too much noise to pass our "good" rating here.

ISO 12,800 prints a good 5 x 7 inch print with overall good contrast and color still available.

ISO 25,600 yields a nice 4 x 6, with good color reproduction for such a high ISO.

The Sony A5100 stands tall in the print quality department as we'd expected, given that it shares the same imaging pipeline as its storied big brother the Sony A6000. Delivering good 16 x 20 inch prints at ISO 1600 is no common feat for a sub-frame camera, and the ability to deliver a usable print at the top of the available ISO range is also always a welcome sign. Sporting the image quality of the A6000 in a smaller, lighter and less expensive package is a neat trick indeed.