Panasonic GX8 Image Quality


Color

Saturation & Hue Accuracy
Slightly lower than average mean saturation levels, with about average hue accuracy.

ISO Sensitivity
100
200
400
800
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 results at different ISOs, and click on the links for larger images.

Saturation. The Panasonic GX8 produces images with slightly muted colors compared to most cameras at default settings. Mean saturation is 108.9% (8.9% oversaturated) at the base ISO of 200, which is a bit lower than the typical camera. Saturation is fairly consistent up to ISO 6400, but falls off to a minimum of 92.9% at ISO 25,600. The Lumix GX8 pushes dark blues moderately and some other colors slightly, but undersaturates yellow a bit more than we'd like. 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 Panasonic GX8 does fairly well here, producing reasonably natural-looking Caucasian skin tones with only a slight push to pinks, though they can look a little flat and yellow with either Auto or Manual white balance in simulated daylight. 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 Panasonic GX8 shifts orange toward yellow and yellow toward green mildly, and cyan is shifted toward blue moderately (for better-looking skies), but most other hue shifts are quite minor. The typical Panasonic yellow to green shift and desaturation is unfortunately noticeable, which makes some yellows look a little dingy. The GX8's mean "delta-C" color error after correction for saturation is 4.91 for JPEGs at the base ISO of 200 (100 is an extended ISO). That's about average these days, and color error remains fairly stable throughout most of the ISO range, with only the highest ISO exhibiting below average hue accuracy. Hue is "what color" the color is.

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

Sensor

Exposure and White Balance

Indoors, incandescent lighting
Warm colors with Auto and Incandescent white balance setting. Good color balance with the Manual setting. Average positive exposure compensation required.

Auto White Balance
+0.3 EV
Incandescent White Balance
+0.3 EV
Manual White Balance
+0.3 EV

Indoors, under normal incandescent lighting, color balance is warm with the Auto white balance setting. Results with the Incandescent setting are also too warm, with a slightly stronger orange-yellow cast. The Manual setting produced accurate results, just a hair on the cool side. The Panasonic GX8 required +0.3 EV 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.)

Outdoors, daylight
Natural colors overall, with a tendency toward high contrast under harsh lighting. About average exposure accuracy.

Auto White Balance,
+0.7 EV
Auto White Balance,
Auto Exposure

Outdoors, the Panasonic GX8 performed well, with natural-looking though slightly cool colors in the Far-field shot. Skin tones are fairly realistic in our "Sunlit" Portrait shot, but perhaps just a little flat and yellow. Exposure accuracy is about average, as the camera required +0.7 EV compensation for our "Sunlit" Portrait shot to keep facial tones reasonably bright. That's typical for this shot. Despite the bright appearance, very few highlights were actually blown in the mannequin's white shirt which is quite good, though there are some very deep shadows that contain good detail, but are somewhat noisy and discolored. The default exposure is a little dim for the Far-field shot, but as a result there were almost no blown highlights, though again there are some very deep shadows that have good detail but are a bit noisy and discolored.

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

Resolution
~ 2,700 lines of strong detail.

Strong detail to
~2,700 lines horizontal
Camera JPEG
Strong detail to
~2,700 lines vertical
Camera JPEG
Strong detail to
~2,700 lines horizontal
ACR converted raw
Strong detail to
~2,700 lines vertical
ACR converted raw

In a camera JPEG, our laboratory resolution chart reveals sharp, distinct line patterns to just over 2,700 lines per picture height horizontally, and to about 2,700 lines in the vertical direction. (Some might argue for higher, but lines begin to merge and aliasing artifacts begin to interfere at these limits.) Complete extinction of the pattern occurs between 3,500 and 3,600 lines per picture height in both directions. We weren't able to extract significantly more high-contrast resolution by processing the Panasonic GX8's RW2 file using Adobe Camera Raw, and the ACR conversion also shows higher color moiré which is practically nonexistent in the camera JPEG.

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
Decent sharpness overall, with only minor edge-enhancement artifacts on high-contrast subjects. Mild to moderate noise suppression visible in the shadows even at base ISO.

Good definition of high-contrast
elements, with just slightly visible
sharpening artifacts.
Subtle detail: Hair
Noise suppression tends to blur
detail in areas of subtle contrast.

Sharpness. The Panasonic GX8 captures fairly sharp, detailed images with a sharp lens, though default sharpening is a bit conservative. Some minor edge enhancement artifacts are visible on high-contrast subjects such as the sharpening "halos" along the lines and text in the crop above left, but default sharpening is actually pretty tame, giving some images a slightly soft look compared to cameras that oversharpen. 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 the effect of noise suppression in the form of smudging of individual strands together in the darker areas of the model's hair, as well as in areas with low local contrast. The GX8 also leaves behind a little more chroma noise than some other brands. Still, this is pretty good noise versus detail processing performance for a 20-megapixel Micro Four Thirds model, leaving plenty of detail intact instead of blurring much of it away in an attempt to hide noise. 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 Panasonic GX8 produces fairly sharp in-camera JPEGs with very good detail. As is almost always the case, better detail can be obtained from carefully processing RAW files than can be seen in the in-camera JPEGs, with fewer sharpening artifacts to boot. Take a look below, to see what we mean:

Base ISO (200)
Camera JPEG, defaults
RAW via Adobe Camera Raw

In the table above, we compare an in-camera JPEG taken at base ISO using default noise reduction and sharpening (on the left) to a matching RAW file converted with Adobe Camera Raw 9.1 using default noise reduction with some strong but tight unsharp masking applied in Photoshop (350%, radius of 0.3 pixels, and a threshold of 0).

As you can see, the in-camera JPEG contains very good detail (the highest we've seen from a MFT camera thus far), however as is usually the case, ACR extracted additional detail, particularly in the red-leaf fabric where it managed to resolve some of the thread pattern. And it produced better color. The ACR conversion also shows less chroma noise at default settings, though it does show more luminance noise after sharpening, especially in areas with little detail. 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 find the noise objectionable.

Bottom line, though, as is usually the case, shooting in RAW mode provides better detail, color, and control than in-camera JPEGs when using a good converter.

ISO & Noise Performance
Pretty good high ISO performance for a Micro Four Thirds model.

Default Noise Reduction
ISO 100 ISO 200 ISO 400
ISO 800 ISO 1600 ISO 3200
ISO 6400 ISO 12,800 ISO 25,600

The Panasonic GX8's images are very detailed and clean at ISOs 100 (extended) and 200, with only minor luminance and chrominance noise detectable in the shadows. ISO 400 is also very detailed, though a touch more noise can be seen upon close inspection. ISO 800 shows slightly higher luminance noise and stronger noise reduction blurring some very fine detail in the process, though overall detail remains quite good. ISO 1600 is of course a little noisier and softer, but fine detail still good. What looks to be a sudden increase in sharpening likely to make up for stronger noise reduction makes luminance noise more obvious with a bit of a crystalline effect at ISO 3200. At ISO 6400 and above, the crystalline effect becomes progressively stronger while fine detail is reduced to the point where very little fine detail is left in the hair at ISO 25,600. Chroma noise also becomes progressively stronger and objectionable at ISO 6400 and above, and there's a strong peppered effect at ISO 12,800 and 25,600 as well. There's also a noticeable drop is saturation at the highest ISOs.

Still, high ISO performance appears to be pretty good and competitive with most 16-megapixel 4/3" rivals, despite the smaller pixels. We're of course pixel-peeping to an extraordinary extent here, since 1:1 images on an LCD screen have little to do with how those same images will appear when printed. See the Print Quality section below for our evaluation of maximum print sizes at each ISO setting.

A note about focus for this shot: We used to shoot this series at f/4, however depth of field became so shallow with larger, high-resolution sensors that it was difficult to keep important areas of this shot in focus, so we have started shooting it at f/8 for 4/3" and larger sensors, the best compromise between depth of field and sharpness.

Extremes: Sunlit, dynamic range and low light tests
Somewhat high default contrast but with very good dynamic range. Very good low-light performance.

+0.3 EV +0.7 EV +1.0 EV

Sunlight. The Panasonic GX8 performed well with the deliberately harsh lighting of this test. Contrast is a little high at its default setting, but dynamic range is pretty good in JPEGs. We felt the +0.7 EV exposure is the best compromise here. Although skin tones around the eyes are a bit dark, we prefer it to the +1.0 EV exposure overall, because very few highlights were clipped. It's really the photographer's choice here as to which direction to go in. For those Panasonic GX8 owners that are going to want to just print an image with little or no tweaking, the +1.0 image would probably produce a better-looking face uncorrected. The bottom line though, is that the Panasonic GX8 performed well with the wide dynamic range of this shot, especially for a Four Thirds sensor. See below for how the Panasonic GX8's sensor performs (RAW mode) in terms of dynamic range.

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.)


Far-field Intelligent D-Range Examples
Off
Low

Panasonic's Intelligent Dynamic Range
The above shots are examples of Panasonic's Intelligent Dynamic Range Control (or iD-Range) at work, with no exposure compensation. Note that the camera does not take multiple shots and merge them as HDR mode does (see below). It's a system that adjusts local contrast and exposure more akin to Nikon's Active D-lighting, Canon's Automatic Lighting Optimization or Sony's Dynamic Range Optimization.

There are three levels of iD-Range available on the Panasonic GX8: Low, Standard and High, plus Auto and Off. It's automatically invoked in iAuto and manually selectable in PASM modes. Here, you can see darker midtones and shadows were progressively boosted as the strength was increased, without blowing many highlights in the process. As a result, though, noise is a little more visible, especially noticeably in areas with little detail such as the sky.


Far-field HDR Examples
Off

HDR mode
Here, you can see the Panasonic GX8's High Dynamic Range mode at work with our Far-field shot. HDR mode takes three images at different exposures and combines them to increase dynamic range. Four settings are available, ranging from Auto to up to +/-3 EV of exposure difference. Mouse over the links, and click on them the view the full resolution files.

Auto and +/-1 EV produced very similar results, while +/-3 dimmed the entire image, so the feature did not work very well for this scene (and we saw the same behavior with our Outdoor Portrait series). Be aware that double images and ghosting is possible when elements in the scene move between frames. Also notice the angle of view is narrower in the HDR images, likely because the images have been cropped and upsized during the optional auto alignment process.

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 compare the Panasonic GX8's dynamic range to its predecessor, the GX7, and also to the Samsung NX500, an APS-C mirrorless ILC.

As you can see from the above graph, the GX8's dynamic range is similar to the GX7's up to ISO 1600, however the GX8 has a slight advantage at its extended low setting of 100, with a value of 12.6 EV versus 12.2 EV for the GX7 at ISO 125. Interestingly, the G7X starts to pull away from the GX8 at ISO 3200 and above, with about a 1/2 stop advantage. Also note the GX8's chart doesn't include a separate ISO 12800 and 25600 data points, as the sensor offers the same sensitivity at those settings. (We still see the expected relationship between shutter speed, aperture and ISO sensitivity at ISO 12800 and 25600, but the GX8 is likely applying "digital" amplification during image processing at ISO 25600, hence the missing data point.)

The Panasonic GX8 lags behind the APS-C-sensored Samsung NX500 across the board, with the Samsung offering up to a 1.3 stop advantage at base ISO (13.9 EV vs 12.6), though the Samsung's advantage diminishes at higher ISOs.

Bottom line: Dynamic range is excellent for a Four Thirds sensor, in fact the best tested to date, though as expected, it's not as good as the best APS-C mirrorless rivals.

Click here to visit the DxOMark page for the Panasonic GX8 for more of their test results and additional comparisons.


  1 fc
11 lux
1/16 fc
0.67 lux
1/16 fc
No NR
ISO
200

1s, f2.8

15s, f2.8

15s, f2.8
ISO
3200

1/15s, f2.8

1s, f2.8

1s, f2.8
ISO
25600

1/125s, f2.8

1/8s, 1 f2.8

1/8s, f2.8

Low Light. The Panasonic Lumix DMC-GX8 performed well in our low light tests, able to capture bright images down to the lowest light level we test at. The darkest level equates to about 1/16 the brightness of average city street lighting at night, so the Panasonic GX8 should be able to take well-exposed photos in almost any environment in which you can see well enough to walk around in.

Using default noise reduction setting, noise is low at ISO 200 and well-controlled at ISO 3200, though as you'd expect, noise is quite high at the maximum ISO of 25,600. We didn't notice any significant issues with hot pixels, though with long exposure noise reduction turned off (rightmost column) there were a number of hot pixels visible at base ISO, as well as a lot of brighter pixels in the shadows. We didn't detect any issues with heat blooming and spotted only mild fixed pattern noise at the highest ISO in our tests.

Auto color balance is just a touch cool particularly at lower light levels, but pretty neutral.

The camera's autofocus system was able to focus on our subject down to almost the 1/16 foot-candle light level unassisted with an f/2.8 lens, which is excellent, especially for a camera with contrast-detect autofocus, though the AF speed slowed down quite a bit. The Panasonic GX8 has a focus-assist light which allows it to autofocus in total darkness, as long as the subject is within range and has sufficient contrast.

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 phase-detect AF systems, digital SLRs tend to do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects. The GX8 uses contrast-detect autofocus, as is found in most point & shoot cameras, so its low-light focusing ability may be less than that of some SLRs with phase-detect systems. That said, though, the larger, more sensitive pixels of the GX8's sensor do better under dim lighting than do the tiny pixels of most point & shoots.

Output Quality

Print Quality
Very good 30 x 40 inch prints at ISO 100/200; a nice 16 x 20 at ISO 1600; a good 4 x 6 at ISO 12,800.

ISO 100 and 200 prints are very good at 30 x 40 inches, with rich colors and nice detail. The 20-megapixel sensor allows for one larger print size here at extended low and base ISO than the GX7 and other Micro Four Thirds cameras with 16-megapixel sensors.

ISO 400 yields a nice 24 x 36 inch print, and an excellent 20 x 30. While the 24 x 36 inch print does pass our official "good" rating and delivers a nice print at that size, for most critical applications the 20 x 30" is superb here.

ISO 800 delivers a very solid 16 x 20 inch print, with good detail for this sensitivity and very low noise. 20 x 30's can definitely be used for all but the most critical applications.

ISO 1600 also yields a quality 16 x 20 inch print (!) which is quite good for this sensor size at this sensitivity. There is the typical mild softening of detail in our target red-leaf swatch, and a negligible amount of noise present in a few flatter areas of our target, but still a very respectable print with otherwise good color and detail throughout.

ISO 3200 produces a good 11 x 14 inch print. All contrast detail is now lost in our tricky red-leaf fabric swatch, but good detail and color reproduction is evident throughout the rest of the print.

ISO 6400 shows a dramatic decrease in print quality, which is common for this sensor size and indeed all but the best digital cameras at this ISO sensitivity. 8 x 10's here can be used in a pinch for less critical applications, but we'll pin our "good" seal of approval on 5 x 7 inch prints here.

ISO 12,800 delivers a good 4 x 6 inch print, which is not bad for such a high ISO at this sensor size.

ISO 25,600 images are a bit too muted and "burned" looking to call good printed at our smallest size, and we recommend avoiding this setting for most applications other than very low-resolution web usage.

The Panasonic GX8 with its new 20-megapixel sensor delivers a solid performance in the print quality department. For starters, the increased resolution over its predecessor (and all other Micro Four Thirds models as of this writing) allows for a larger print size of 30 x 40 inches at base and extended low ISOs. Furthermore, the Venus Engine processor ups the IQ game and delivers larger available print sizes at ISOs 400, 1600 and 3200. Therefore, users can expect high quality prints from the Panasonic GX8, and if they remain at ISO 3200 and below they will not be disappointed.

About our print-quality testing: Our "Reference Printer"

Testing hundreds of digital cameras, we've found that you can only tell 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 routinely print sample images from the cameras we test on our Canon imagePROGRAF PRO-1000 printer, which we named our "Printer of the Year" in our 2015 COTY awards.

The Canon PRO-1000 has a lot of characteristics that make it a natural to use for our "reference printer." When it comes to judging how well a camera's photos print, resolution and precise rendering are paramount. The PRO-1000's more than 18,000 individual nozzles combine with an air feeding system that provides exceptional droplet-placement accuracy. Its 11-color LUCIA PRO ink system delivers a wide color gamut and dense blacks, giving us a true sense of the cameras' image quality. To best see fine details, we've always printed on glossy paper, so the PRO-1000's "Chroma Optimizer" overcoat that minimizes "bronzing" or gloss differential is important to us. (Prior to the PRO-1000, we've always used dye-based printers, in part to avoid the bronzing problems with pigment-based inks.) Finally, we just don't have time to deal with clogged inkjet heads, and the PRO-1000 does better in that respect than any printer we've ever used. If you don't run them every day or two, inkjet printers tend to clog. Canon's thermal-inkjet technology is inherently less clog-prone than other approaches, but the PRO-1000 takes this a step further, with sensors that monitor every inkjet nozzle. If one clogs, it will assign another to take over its duties. In exchange for a tiny amount of print speed, this lets you defer cleaning cycles, which translates into significant ink savings. In our normal workflow, we'll often crank out a hundred or more letter-size prints in a session, but then leave the printer to sit for anywhere from days to weeks before the next camera comes along. In over a year of use, we've never had to run a nozzle-cleaning cycle on our PRO-1000.

See our Canon PRO-1000 review for a full overview of the printer from the viewpoint of a fine-art photographer.

*Disclosure: Canon provided us with the PRO-1000 and a supply of ink to use in our testing, and we receive advertising consideration for including this mention when we talk about camera print quality. Our decision to use the PRO-1000 was driven by the printer itself, though, prior to any discussion with Canon on the topic. (We'd actually been using an old Pixma PRO 9500II dye-based printer for years previously, and paying for our own ink, until we decided that the PRO-1000 was the next-generation printer we'd been waiting for.)

 

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Panasonic Lumix DMC-GX8 Photo Gallery .

Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Panasonic Lumix DMC-GX8 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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