Panasonic GH2 Exposure

Saturation & Hue Accuracy
Fairly accurate saturation levels over most of the spectrum. Some issues with hue accuracy, primarily in orange through yellows.

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. Click for a larger image.

Saturation. The Panasonic GH2 produced fairly accurate saturation levels at default settings. The camera pushes reds, dark greens and purples very slightly, dark blues a fair bit, while slightly undersaturating some greens, yellows cyans and light purple. Average saturation is 103.4% (only 3.4% oversaturated). That's a bit lower than most cameras these days, including other recent Panasonics CSCs. Some people may feel default colors are slightly muted, especially yellows. 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. Here, the Panasonic GH2 did well, producing natural-looking Caucasian skin tones, though just slightly on the pinkish side. 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 GH2 pushed cyan toward blue slightly (but much less so than most cameras), red toward orange, orange toward yellow and yellow toward green. Some greens were also pushed toward yellow. In the orange through yellow range, shifts were pronounced enough that colors there are poorly delineated from each other and have a greenish hue. These shifts were especially apparent in the yellow through orange yarn of our Still Life test image JPEGs. The camera's average "delta-C" color error of 6.49 is higher than average compared to recent competitors, but that's not atypical for Panasonic. Its concentration in this one part of the spectrum makes it pretty noticeable, though. The good news is the orange-yellow shifts are significantly mitigated by working with RAW files and using a good-quality third-party RAW converter, as can be seen in this Adobe Camera Raw conversion. Delta-C color error improved significantly using Adobe Camera Raw defaults, to only 3.88, which is an excellent score. Hue is "what color" the color is.

"Film" Modes
The Panasonic GH2 offers nine preset "Film" modes. You can adjust contrast, saturation, sharpness and noise reduction for any of the modes, and then save the settings as one of two custom options.

Mouse over the links above to see the effect of the presets on our Still Life target. You can click on a link to load the full resolution image.

Saturation Adjustment
The Panasonic GH2 lets you adjust the image saturation, contrast, and sharpness in five steps each. As can be seen below, the saturation adjustment was very subtle. We usually argue in favor of more subtle adjustments for saturation on the cameras we test, but the Panasonic GH2 goes a bit too far in that direction; we'd like to see a wider range here (more steps), but still with the fine steps the GH2 currently offers.

Saturation Adjustment Examples
-2	0	+2

The table above shows results with the default as well as the two "extreme" saturation settings. 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
Slightly warm cast with Auto, very warm with Incandescent, but good color balance with the Manual and 2,600 Kelvin white balance settings. Average positive exposure compensation required.

Auto White Balance +0.3 EV	Incandescent White Balance +0.3 EV
Manual White Balance +0.3 EV	2,600 Kelvin +0.3 EV

Indoors, under normal incandescent lighting, color balance was just slightly warm with the Auto white balance setting, though the Panasonic GH2 did much better than most digital SLRs in this regard. (While slightly warm, results with the Auto setting were quite acceptable, and many users in fact prefer a slightly warm look in situations like this, to better represent the mood of the original lighting.) Results with the Incandescent setting were much warmer; the Incandescent setting looks like it might be adjusted to match professional studio lighting, a little odd for a consumer camera model. The Manual setting produced the most accurate results, though the 2,600 Kelvin setting wasn't far off the mark either, being just slightly cooler. The Panasonic GH2 required +0.3 EV exposure compensation here, which is about average for this shot among the cameras we've tested. (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 looking colors overall, though a tendency toward high contrast under harsh lighting. Average exposure accuracy.

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

Outdoors, the Panasonic GH2 performed pretty well, with good color and exposure in the outdoor Far-field house shot. The Panasonic Lumix GH2 required an average amount of positive exposure compensation (+0.7 EV) to keep facial tones reasonably bright in our "Sunlit" Portrait test, which led to blown highlights in her shirt and flowers. Default contrast is on the high side, but fortunately, there's are contrast and dynamic range adjustments to help compensate. Overall, good results here, especially when the contrast setting is turned down (see Extremes section below).

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

Resolution
Very high resolution, 2,100 ~ 2,200 lines of strong detail.

Strong detail to ~2,200 lines horizontal Camera JPEG	Strong detail to ~2,100 lines vertical Camera JPEG
Strong detail to ~2,200 lines horizontal ACR processed RW2	Strong detail to ~2,100 lines vertical ACR processed RW2

In camera JPEGs our laboratory resolution chart revealed sharp, distinct line patterns down to about 2,200 lines per picture height horizontally, and about 2,100 lines in the vertical direction. Extinction didn't occur until about 3,000 lines horizontally and vertically. We weren't able to extract much more resolution by processing the Panasonic GH2's RW2 files using Adobe Camera Raw 6.3, but ACR did hold definition in the target lines better than the camera's own JPEG conversion did, making the target lines more distinct at higher spacial frequencies, as well as extending complete extinction of the pattern up to the 4,000 line limit of our chart.

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 sharpness overall, with only minor edge-enhancement artifacts on high-contrast subjects. Good detail, but moderate noise suppression visible at even the base ISO.

Very good definition of high-contrast elements with some minor sharpening artifacts.	Subtle detail: Hair Noise suppression tends to blur detail in areas of subtle contrast.

Sharpness. The Panasonic GH2 captures sharp, detailed images overall, with only minor edge enhancement artifacts visible on high-contrast subjects such as the branches in the crop above left. Very 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.

JPEG	RAW

Detail. The crop above right shows some moderate noise suppression artifacts in the model's hair even at ISO 160, smudging individual strands together, though quite a few strands are visible in the lighter shadows. Overall detail is pretty good, but like previous Panasonic models, there are some odd color blotches (see JPEG crop at right), that we believe may be the result of insufficient anti-aliasing filtering, and the aliasing/demosaicing problems that it produces. (We also saw these with previous G series cameras, but only in the very fine, reddish detail of the mannequin's hair. This is something that we've seen with a number of other cameras in the past, including several SLRs.) The blue blotches do not appear in Adobe Camera Raw converted files (mouse over the RAW link), even when both luminance an chrominance noise reduction is turned off. 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.

Intelligent Resolution
The Panasonic GH2 offers four levels of "Intelligent Resolution", which essentially sharpens fine detail while leaving areas with little or no detail (such as a cloudless sky) untouched to keep visible noise to a minimum. To see how well it works, compare the crops below at each setting.

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.

As you can see, fine detail has progressively stronger sharpening applied as the setting is increased, while the noise in the sky is not affected. The increased sharpening and noise reduction does tend to coarsen and blur fine detail at higher settings, though. The pine needles in the trees behind the house are a good illustration of this effect. Still, we think most users will be pleased with the extra "pop" in apparent detail Intelligent Resolution provides to JPEGs, at least for natural subjects.

RAW vs In-Camera JPEGs
As noted above, the Panasonic GH2 produces sharp in-camera JPEGs. As is almost always the case, though, quite a bit more detail can be obtained from carefully processing RAW files than can be seen in the in-camera JPEGs. The Panasonic GH2's JPEGs are pretty good straight from the camera, but it's surprising how much more detail is visible after processing in a good RAW converter. Take a look below, to see what we mean:

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.

SilkyPix 3.1 SE (the RAW converter Panasonic bundles with their RAW-capable cameras) is pretty sophisticated in the controls it provides for tweaking your photos. In the crop above, we turned the in-application sharpening control down to zero and used only its output unsharp masking, which we set to 150%, a radius of 0.3 pixels, and a threshold of 0. All other settings were the defaults. File output is actually a logical place to apply unsharp masking, as you'll want to use different sharpening settings for printing at different sizes, but we found it awkward not being able to preview the effect of the unsharp masking on-screen.

Adobe Camera Raw 6.3 was used for the ACR conversion version. Default settings were used, though no sharpening was applied during conversion. The image was then sharpened in Photoshop using unsharp masking at 300% with a radius of 0.3 pixel.

As you can see, the RAW conversions both contain more fine detail than the camera JPEG. The SilkyPix conversion has higher default contrast and colors match the JPEGs better than ACR. SilkyPix also seems to applies more default noise reduction than ACR. The ACR conversion shows quite bit more noise especially in the areas of with little detail such as sky. 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. Bottom line: the Panasonic DMC-GH2 rewards RAW shooters with really excellent detail, but be prepared to use some noise reduction even at relatively modest ISOs if you're not going to use the included SilkyPix software.

ISO & Noise Performance
Low to moderate noise up to ISO 400, moderate to high at higher ISOs. Some noise reduction already evident at base ISO.

Default Noise Reduction
ISO 160	ISO 200	ISO 400
ISO 800	ISO 1,600	ISO 3,200
ISO 6,400	ISO 12,800

The Panasonic GH2's images look fairly clean at ISOs 160 and 200, though fine detail is already impacted by the default noise reduction at ISO 160. Some chroma noise is also visible in the shadows and darker strands of hair. As mentioned previously, demosaicing errors in the hair cause what looks like blue chroma noise as well, something we've seen in previous Panasonics, as well as some other brands. We start to see some more noticeable smudging due to noise reduction at ISO 400, but detail is still pretty good, with just a bit more chroma noise creeping into the shadows. The effects of stronger noise reduction are more evident at ISO 800, where there's a more noticeable increase in blurring of fine detail and much less chroma noise than at ISO 400. At ISO 1,600 we see much stronger luminance noise, as well as some yellow blotches in the shadows and darker midtones. At ISO 3,200, little fine detail is left, an the yellow blotching is also more widespread and gives the entire image a yellow cast. Noise gets pretty ugly at ISO 6,400: there's a lot of luminance noise, shadows and midtones are quite yellowish, and the camera's noise reduction coupled with sharpening artifacts produce a prominent peppering effect. ISO 12,800 is of course even worse, with more obvious noise reduction artifacts, very strong yellow blotches in brighter areas, and purple blotches in darker areas.

ISO 160 Default NR	ISO 160 Lowest NR

To the right, you can compare noise and detail retention at ISO 160 with the Panasonic GH2's noise reduction set at default, and at the lowest setting. Mouse over the links to load the corresponding crops, and click on the links to get to the full resolution images. As you can see, the lowest NR setting shows more luminance noise in the background, but also retains more detail in the fabric and wood. We're used to seeing noticeable detail loss due to noise reduction at higher ISOs in SLRs (and at all ISOs in point & shoots), but the GH2 shows it more than the typical SLR at base ISO. In the GH2's defense, though, its base ISO of 160 is higher than most other CSC/SLR cameras, so we'd expect to see higher noise, and the GH2's higher 16-megapixel resolution will partially offset the loss of detail compared to other current Micro Four-Thirds models which have a maximum 12-megapixel resolution.

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 the indoor portrait 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 and low light tests
High resolution with good overall detail, but somewhat high default contrast and limited dynamic range. Very good low-light performance.

+0.3 EV	+0.7 EV	+1.0 EV

Sunlight. The Panasonic Lumix DMC-GH2 struggled a bit with the deliberately harsh lighting of this test, as contrast was a little high at its default setting, and the dynamic range somewhat limited. Although skin tones in the face are a bit dark at +0.7 EV with the default contrast, we preferred it to +1.0 EV exposure overall, because there were fewer clipped highlights. Depending on the photographer, you could lean one way or the other. Pros and advanced users will want to shoot darker, to hold highlight detail. For those Panasonic GH2 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 uncorrected in this situation. The bottom line though, is that the Panasonic GH2 had difficulty with the wide dynamic range of this shot, at least with its default settings.

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.)

Contrast Adjustment
As mentioned previously, the camera's limited contrast adjustment was at least some help in handling the harsh lighting.

Minimum Contrast
Contrast set to lowest, +0.7 EV	Contrast set to lowest, Auto Exposure

At its lowest contrast setting, the Panasonic GH2 did a slightly better job of preserving highlight detail while maintaining fairly natural-looking skin tones, though it helped more with bringing out the shadows and darker midtones. Overall, the camera's limited dynamic range makes it perform a bit below average in this situation.

Contrast Adjustment Examples
-2	0	+2

The table above shows results with the default as well as the two "extreme" contrast settings. Click on any thumbnail above, then click again to see the full-sized image. Unlike the Saturation adjustment, the control for Contrast is not quite as subtle in its effect. It seems to basically leave the strongest highlights alone, and then apply a proportional boost to tones as it moves down the tone curve. To make the most of it in a shot like this, you'd want to drop the exposure to hold the highlights and then apply a good amount of contrast reduction (probably the maximum, the steps are pretty small).

The Panasonic GH2's contrast adjustment helps a little with the strong highlights here, but we'd really like to see more steps of this size, covering a slightly greater range. And even with the lowest contrast setting, the dynamic range isn't terribly impressive. Lowering the contrast helps the visual appearance of images such as these, but doesn't result in any significant extension of the tonal scale, in either bright highlights or deep shadows.

Panasonic's Intelligent Dynamic Range
The above shots are examples of Panasonic's Intelligent Dynamic Range (or iDynamic) at work, with no exposure compensation. iDynamic appears to be a more advanced version of iExposure, capable of reducing both blocked shadows and clipped highlights, and is currently only found on the GH2 and GF2 system cameras. iExposure, which worked by raising sensitivity in dark areas to bring out more detail is no longer offered.

There are three levels of iDynamic available on the GH2: Low, Standard and High, plus Off. It's automatically invoked in iAuto mode and manually selectable in PASM mods. For our Outdoor Portrait shot, all three settings were an improvement over the Off setting, pulling detail out of the shadows and delivering a better exposure overall, but the Standard and High settings produced almost identical results compared to Low. All shots above used the base ISO of 160 equivalent. There were few highlights blown to begin with at default exposure, so we weren't able to determine how well highlight preservation works. We suspect that shooting with iDynamic enabled at an exposure compensation of +0.7 EV would have brightened things up without blowing the highlights. - But as always, we had to draw the line somewhere on testing, in the interests of getting this review out and then getting on to other cameras in our never-ending backlog. Bottom line, though, iDynamic seems to provide a useful extension to the practical dynamic range of the Panasonic GH2. (It's not likely increasing the technically defined dynamic range of the sensor any, but it can make for much more usable/printable images when working under tough lighting conditions.)

As you can see, iDynamic had very little effect on our Far-field House shot, likely because there were few blown highlights and completely blocked shadows to begin with, though we were surprised that it didn't attempt to brighten the shadows. Perhaps the shadow areas weren't a large enough percentage of the total scene to trigger the effect.

Face Detection
Off at 0 EV	On at 0 EV	iAuto at 0 EV

Face Detection
Like most Point & Shoot cameras these days (and most DSLRs in Live View mode), the Panasonic Lumix DMC-GH2 has the ability to detect faces, and adjust exposure and focus accordingly. The GH2 does it automatically in Intelligent Auto (iAuto) mode, when a Portrait scene mode is selected, or when Face Detection AF mode is selected. As you can see from the examples above, it works fairly well, as the image with face detection enabled is better exposed for the face, and iAuto mode definitely tones down contrast some, which should deliver very nice exposures, even under very difficult lighting such as this.

	1 fc 11 lux	1/2 fc 5.5 lux	1/4 fc 2.7 lux	1/8 fc 1.3 lux	1/16 fc 0.67 lux	1/16fc No NR
ISO 160	1.3 sec f2.8	2.5 sec f2.8	5 sec f2.8	10 sec f2.8	20 sec f2.8	20 sec f2.8
ISO 200	1 sec f2.8	2 sec f2.8	4 sec f2.8	8 sec f2.8	15 sec f2.8	15 sec f2.8
ISO 400	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	4 sec f2.8	8 sec f2.8	8 sec f2.8
ISO 800	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	4 sec f2.8	4 sec f2.8
ISO 1600	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	2 sec f2.8
ISO 3200	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	1 sec f2.8
ISO 6400	1/30 sec f2.8	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	0.5 sec f2.8
ISO 12800	1/60 sec f2.8	1/30 sec f2.8	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	1/4 sec f2.8

Low Light. The Panasonic DMC-GH2 performed well in our low light test, capturing bright images down to the lowest light level we test at, at all ISO settings. This darkest level equates to about 1/16 the brightness of average city street lighting at night, so the Panasonic GH2 should be able to take well-exposed photos in almost any environment in which you can see well enough to walk around in. The GH2's auto exposure system struggled a bit at the lowest light levels, so we used manual mode for these shots. Automatic white balance was pretty good (just slightly cool), something that's not a given at such low light levels. Using the default noise reduction setting, noise was low to moderate up to ISO 1,600. At ISOs 3,200 and above, noise was a bit high compared to most DSLRs these days, but with hardly any of horizontal banding we saw from the Panasonic GH1 at the same light levels.

The camera's autofocus system was able to focus on the subject down to below the 1/16 foot-candle light level unassisted, which is excellent for a camera using contrast-detect autofocus. The Panasonic GH2 does have a focus-assist light option 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 GH2 uses contrast-detect autofocus, as is found in most point & shoot cameras, so its low-light focusing ability is less than that of some SLRs with phase-detect systems. That said, though, the larger, more sensitive pixels of the GH2's sensor do better under dim lighting than do the tiny pixels of most point & shoots, (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.)

Print Quality

ISO 160 shots are a bit soft at 24 x 36, but look quite good at 20 x 30 inches, with good detail but slightly muted color. That's unfortunately the way JPEGs look from most Panasonic cameras, and the GH2 is no exception.

ISO 200 shots are slightly softer than the 160 shots, but still very good at 16 x 20 inches.

ISO 400 images also look very good at 16 x 20 inches.

ISO 800 shots start to soften a little more at 16 x 20, and colors darken a bit. Results look better printed at 13 x 19 inches.

ISO 1,600 prints are good, if a little soft, at 8 x 10 inches. Colors are a bit darker still, and reds start to lose detail.

ISO 3,200 shots look better at 5 x 7 inches, though the shadows and mids do appear somewhat dark.

ISOs 6,400/12,800 do not yield usable 4 x 6s and are best avoided if possible.

In terms of resolution, the Panasonic GH2 does quite well, with good detail at very large print sizes from ISO 160 to 800. When shooting in low light, however, we recommend capturing a RAW image as well, as color muting and inaccuracy intensifies as ISO rises.

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 on the Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)