Olympus E-PM2 Exposure

Saturation & Hue Accuracy
Accurate saturation levels with very good hue accuracy.

Saturation. The Olympus E-PM2 pushes reds a fair bit, but most other colors are pretty close to bang on in terms of saturation. Default saturation at base ISO is 108% (8% oversaturated), which is a bit lower than average; that is, it's more accurate than most. Saturation remains fairly stable across the ISO range, except at ISO 6,400 and above where it falls off, particularly in purples and dark green. You can always adjust saturation, or select a different picture mode to adjust color to your tastes. Most consumer digital cameras produce color that's more highly saturated (more intense) than what's found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. Here, the Olympus E-PM2 did fairly well, producing natural-looking Caucasian skin tones, just slightly on the warm 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 Olympus PEN E-PM2 does shift cyan toward blue, light green toward yellow, oranges toward yellow, etc., but shifts are fairly minor. (The shift from cyan to blue is much less pronounced than most cameras, leaving sunny sky colors a little warmer than most.) Overall hue accuracy is quite good with a Delta-C color error after correction for saturation of 4.13 at base ISO, which is better than average. Hue is "what color" the color is.

Saturation Adjustment
The Olympus E-PM2 lets you adjust the image saturation, contrast, and sharpness in five steps each. As can be seen below, the saturation adjustment was quite effective, covers a useful range, and does a good job of not impacting contrast.

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.

Exposure and White Balance

Indoors, incandescent lighting
Very warm cast with Auto White Balance, cool with 2,600K setting, but good color with the Incandescent and Manual settings. Average exposure compensation required.

Indoors, under normal incandescent lighting, color balance was very warm and orange using the Auto white balance setting. Results with the Incandescent setting were quite good, almost identical to the Manual setting, which was the most accurate. The 2,600 Kelvin setting was quite cool with a blue-green tint. The Olympus E-PM2 required an average amount of positive exposure compensation here, at +0.3 EV. (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, with good exposure.

Outdoors, the Olympus E-PM2 performed well, with pleasing if slightly warm colors, and good exposure. We prefer the skintones with the Auto white balance setting in our "Sunlit" Portrait shot, though Manual white balance produced very similar results. The Olympus E-PM2 required an average amount of positive exposure compensation (+0.7 EV) to keep facial tones reasonably bright. Default contrast is a bit high, but despite the bright appearance there are very few blown highlights in the mannequin's shirt and flowers, which is much better than average. The Far-field shot is just slightly underexposed at default settings, but has almost no blown highlights, though there are some deep shadows. Noise in all but the deepest shadows is however very low for a Micro Four Thirds camera.

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

Resolution
Very high resolution, ~2,230 lines of strong detail in JPEGs, about the same from processed raw files.

In-camera JPEGs our laboratory resolution chart reveals sharp, distinct line patterns down to about 2,30 lines per picture height in both the horizontal and vertical direction before aliasing artifacts start to interfere with the pattern. Complete extinction of the pattern doesn't occur until about 3,000 to 3,200 lines, though. Adobe Camera Raw wasn't able to extract more resolution here, though color moiré is more apparent near the limits of resolution. 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
Good sharpness overall, though edge-enhancement artifacts on high-contrast subjects are visible. Mild noise suppression visible in the shadows.

Sharpness. The Olympus PEN E-PM2 captures sharp images overall, though edge enhancement artifacts are visible on high-contrast subjects such as sharpening halos around the thicker branches and pine cones in the crop above left. Still, results are pretty good as we've seen higher default sharpening from other cameras. 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 some fairly mild noise suppression artifacts in the darkest areas of the model's hair, smudging individual strands together, though quite a few strands remain visible. Overall detail is very good for a 16-megapixel Micro Four Thirds model, though there are some demosaicing errors and aliasing artifacts visible in the hair, indicating that the E-PM2's low pass filter is fairly weak. 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 Olympus E-PM2 produces sharp, detailed in-camera JPEGs, though with some visible sharpening artifacts at default settings. As is almost always the case, though, more detail can be obtained from carefully processing raw files than can be seen in the in-camera JPEGs. 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. The SuperFine camera JPEG and Olympus [ib] conversion used default settings, while Adobe Camera Raw conversion was sharpened in Photoshop using unsharp mask of 300% with a radius of 0.3.

As you can see, the Olympus [ib] conversion resulted in an image very similar to the in-camera JPEG in terms of detail, color and contrast. The Adobe Camera Raw (version 7.4) conversion however contains fine detail superior to the camera's SuperFine JPEG or the Olympus software conversion at default settings, especially noticeable in the pine needles, though it does leave more noise. Nevertheless, like previous Olympus PEN cameras, the E-PM2 rewards raw shooters with even better detail when using a good quality raw converter.

ISO & Noise Performance
Very good noise versus detail up to ISO 1,600.

The Olympus E-PM2's high ISO performance is nearly identical to the E-M5's. Images are quite clean and detailed at ISOs 200 though 800, though some minor chroma noise is visible in the shadows. At ISO 1,600, we see some minor detail loss due to stronger noise and noise reduction efforts, as well as more visible chroma noise in the shadows, but detail is still very strong. At ISO 3,200, additional blurring occurs reducing fine detail, though chroma noise is better controlled. ISO 6,400 shows a lot more luminance noise, as well as another decrease in fine detail and also a reduction in saturation. ISO 12,800 is very noisy, with strong yellow blotching in the shadows. At ISO 25,600, noise and noise reduction is very strong smudging out almost all fine detail, and a lot of blue, purple, and yellow chroma noise is present as well.

Overall, though, high ISO noise performance matches the best we've seen from a Micro Four Thirds model thus far, and competes well with most APS-C models. As always, see the Print Quality section below for maximum recommended print sizes at each ISO.

A note about focus for this shot: We shoot this image at f/4, 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. 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 about it; we already know it. :-) The focus target position will simply have been adjusted to insure that the rest of the scene is focused properly.

Extremes: Sunlit, dynamic range and low light tests
High resolution with very good dynamic range. Good low-light performance as well.

Sunlight. The Olympus E-PM2 did very well with this difficult shot, requiring the average amount of exposure compensation (+0.7 EV) to keep the mannequin's face reasonably bright in this harsh lighting. As mentioned previously, despite the bright appearance of the mannequin's shirt, dynamic range was surprisingly good, with very few highlights blown and very good detail in the shadows as well. Performance here was well above average compared to most Micro Four Thirds models.

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 Olympus E-PM2 JPEG file with a nominally-exposed density step target (Stouffer 4110). At the base ISO of 200 (the optimal ISO) and with default settings, the graph shows 12.4 f-stops of total dynamic range, with 8.87 f-stops at the "High" Quality level. Roll-off at the highlight end of the curve is gradual, but for shadows it isn't quite as well-behaved, which could lead to some minor gradation in very deep shadows. Still, these are are excellent results for a Micro Four Thirds sensor, rivaling many APS-C models. Compared to the Olympus E-PL5 which uses the identical sensor and processor as far as we know, the E-PM2 scored pretty much the same, as expected, especially when the margin of error for this test is taken into account. (This measurement has a margin of error of about 1/3 f-stop, so differences of less than 0.33 can be ignored.)

Raw. The graph at right is from the same Stouffer 4110 stepchart image captured as a raw (.ORF) file, processed with Adobe Camera Raw using the Auto setting, then manually tweaked from there. As can be seen, the score at the highest quality level increased from 8.87 to 9.65 f-stops, while total dynamic range increased less than 1/2 f-stop from 12.4 to 12.8. Again, these results are much better than average for a Micro Four Thirds sensor, slightly better than the Olympus E-PL5, and almost as good as the best APS-C sensors. 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 higher quality thresholds.

Contrast Adjustment
The camera's contrast adjustment was some help in handling the harsh lighting in our "Sunlit" Portrait and Far-field shots.

At its lowest contrast setting, the Olympus E-PM2 did a better job of revealing shadow detail, while maintaining fairly natural-looking skin tones. There were just a few blown highlights to begin with in both these shots so the decreased contrast setting left most highlights alone, but it did bring out more shadow and darker midtone detail.

The shots above show the results of the minimum, default and maximum contrast settings. While you can see the extremes, it's pretty hard to evaluate small differences in contrast on small thumbnails like these, click on any thumbnail to go to the full-size image.  As you can see, the E-PM2's contrast setting is effective on both highlights and shadows, and didn't impact saturation much, which is a good thing.

Gradation
Similar to dynamic range optimization systems from other manufacturers, the Olympus E-PM2's Gradation setting applies local contrast adjustments in an attempt to preserve shadow detail and prevent highlight clipping with the Auto setting. Above are examples of the Normal (default), Low Key, Auto, and High Key settings applied to our "Sunlit" Portrait shot with +0.3 EV exposure compensation. Mouse over the links to load the associated thumbnail and histogram, and click on the links to visit the full resolution image.

As you can see, the Low Key setting applies Gradation for making subjects darker (in the thumbnail and histogram above, you can see that the camera shifted levels to the left, darkening the image dramatically), while the High Key setting does the opposite for brighter subjects (shifting levels to the right so that lighter tones are blown, but darker ones are opened up). The Auto setting did a good job at toning down highlights and bringing up shadows and darker midtones without making the image too flat-looking or washed-out.

Face Detection
Like most cameras these days, the Olympus E-PM2 has the ability to detect faces, and adjust exposure and focus accordingly. The E-PM2 does it automatically in 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 well, as the image with face detection enabled is much better exposed for the face without having to use exposure compensation. The Full Auto setting worked even better by choosing a larger aperture (f/3.5). An excellent performance under very difficult lighting such as this.

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.)

Low Light. The Olympus E-PM2 performed well in low lighting, capturing bright exposures at our lowest light level at all ISOs. Noise was well controlled up to ISO 3,200, though there's some chroma noise noticeable in darker shadows at lower light levels. There are a few bright or hot pixels visible here and there at all ISOs. (The E-PM2 does offer pixel mapping, so hot/dead pixels can be mapped out without a trip to a service center.)

White balance was fairly neutral using the Auto setting, just slightly cool at most ISOs, though blacks and dark greys took on a slightly reddish tint at lower light levels. Some very minor horizontal banding can be seen at the highest ISOs and lowest light levels, but nothing to be concerned about.

The camera's autofocus system was able to focus on our subject down to below the 1/16 foot-candle light level unassisted with an f/2.8 lens, which is excellent for a camera using contrast-detect autofocus, and in total darkness with the aid of its focus assist lamp.

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 E-PM2 uses contrast-detect autofocus, as is found in most point & shoot cameras, so its low-light focusing ability is less than that of most SLRs with phase-detect systems. That said, though, the larger, more sensitive pixels of the E-PM2'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

Prints a nice 24 x 36 at ISO 200; ISO 1600 capable of a good 13 x 19 inch print; with a good 4 x 6 at ISO 12,800.

ISO 200 prints look very good at 24 x 36 inches, and yields a suitable wall display print up to 36 x 48. 

ISO 400 prints are nice and crisp at 20 x 30, with minor softening in the red swatch of our test target (which is typical for many cameras); capable of a nice wall display print up to 30 x 40.

ISO 800 yields a good 16 x 20 inch print with the exception of a loss in contrast in our red swatch, but is otherwise sharp with vibrant colors.

ISO 1600 prints look good at 13 x 19 inches, with minor noise in the shadows and minor previously mentioned softness; suitable for less critical applications at 16 x 20 inches.

ISO 3200 yields prints that we consider good at 11 x 14, but a lot of people will find 13 x 19 perfectly acceptable.

ISO 6400 prints a nice 8 x 10 for this ISO, with only minor grain in the shadows of our target.

ISO 12,800 yields a decent 4 x 6 inch print, with nice color for such a high ISO.

ISO 25,600 prints are a bit too grainy to be called good at 4 x 6.

The Olympus E-PM2 is capable of producing nice large prints at low ISOs, outstanding for its price. It demonstrates excellent high ISO performance up to ISO 1600, and makes surprisingly nice-looking 8 x 10s at ISO 6400. Please note that we shoot these test shots with our sharp reference lenses in order to show what the camera body is capable of, and results with the kit lenses may vary somewhat.

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.)