Olympus E-PM1 Exposure

Saturation & Hue Accuracy
Good color and very good hue accuracy, with pretty good saturation as well.

Saturation. The Olympus PEN E-PM1 pushes reds a fair bit, but most other colors are either about right or only slightly oversaturated. Default saturation is 109.1% (9.1% oversaturated), which is actually slightly lower than average; that is, it's more accurate than most. 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 PEN E-PM1 did well, producing fairly natural-looking skin tones, just slightly on the pinkish side. Darker skin tones show more warmth, but should still be within acceptable limits. 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-PM1 did push cyan toward blue and oranges slightly toward yellow, but shifts were relatively minor to 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.) Overall hue accuracy was very good with a Delta-C color error of only 4.05, which is much better than average. Hue is "what color" the color is.

Color Modes
The Olympus PEN E-PM1 offers six preset color modes, as well as six "Art Filter" modes. You can tweak contrast, saturation, gradation and other parameters (depending on the mode). Changes to each picture mode are saved separately, and you can define your own Custom setting as well.

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. "Natural" is the default.

Saturation Adjustment
The Olympus E-PM1 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, but good color with the Incandescent and Manual settings. Average exposure compensation required.

Indoors, under normal incandescent lighting, color balance was quite warm and orange using the Auto white balance setting. Results with the Incandescent setting were quite good, though, just a touch warmer than the Manual setting which was the most accurate. The 2,600 Kelvin setting was quite cool with a blue-green tint. The Olympus E-PM1 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, though outdoor images were slightly underexposed at default exposure.

Outdoors, the Olympus E-PM1 performed reasonably well, with good color though exposure was a little dim at default settings. The Olympus E-PM1 required an above average amount of positive exposure compensation (+1.0 EV) to keep facial tones reasonably bright on the "Sunlit" Portrait shot. Default contrast was a bit high, though there were only a few blown highlights in the mannequin's shirt and flower. The Far-field shot was slightly underexposed at default settings, but had no blown highlights, though there were some deep shadows that were a bit noisy.

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

Resolution
High resolution, ~1,700 lines of strong detail in JPEGs, up to about 1,900 lines from processed RAW files.

In camera JPEGs our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,700 lines per picture height in both the horizontal and vertical direction before aliasing artifacts started interfering with the pattern. Complete extinction of the pattern didn't occur until about 2,700 to 2,800 lines, though. Adobe Camera RAW was able to extract more resolution, to about 1,900 lines in both directions, though color moire was more apparent. 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-PM1 captures fairly sharp images overall, though edge enhancement artifacts are visible on high-contrast subjects such as halo around the thicker branches and pine cones in the crop above left. 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 pretty good for a Micro Four Thirds model. 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-PM1 produces fairly sharp, detailed in-camera JPEGs, though with 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 super fine camera JPEG and Olympus [ib] conversion used default settings, while Adobe Camera Raw conversion was sharpened in Photoshop using unsharp mask of 350% 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 6.6) conversion however contains more fine detail than the camera SuperFine JPEG or Olympus software conversion at default settings, which is especially noticeable in the pine needles, though it does leave quite a bit more noise. Nevertheless, like previous Olympus PEN cameras, the E-PM1 rewards RAW shooters with excellent detail when using a good quality RAW converter. By comparing full resolution images, you can also see that we were able to recover much of the clipped highlight detail in the clouds above the crop area using Adobe Camera Raw, another advantage of shooting RAW.

ISO & Noise Performance
Low noise and pretty good detail up to ISO 800, moderate to high noise at higher ISOs.

The Olympus PEN E-PM1's images are quite clean and detailed at ISO 200, the base ISO, though some minor chroma noise is already visible in the shadows. Detail is still very good at ISO 400, with just a bit more blurring and a hint more chroma noise creeping into the shadows. ISO 800 is noticeably softer with more smudging due to stronger noise reduction, but detail is still pretty good for a Micro Four Thirds sensor. At ISO 1,600, we see additional detail loss due to stronger smudging, as well as more obvious purple and yellow blotches in shadow areas. At ISO 3,200, noise grain is stronger, blurring fine detail even further despite the weaker noise reduction. Chroma noise is better controlled at ISO 3,200 though. Noise and the effects of noise reduction are quite obvious ISO 6,400, obscuring almost all fine detail and making shadows quite purplish while lighter tones have yellow blotching. Overall color balance also became cooler with a greenish tint at ISO 6,400 and above. Colors were also darker and less saturated. By ISO 12,800, noise grain is the dominant feature with very little detail left, and a lot of chroma noise was present as well. Overall, noise performance is very similar to other recent Olympus PEN models which is good, though not as good as 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 good overall detail, though somewhat limited dynamic range. Good low-light performance, but metering struggled a bit at lower light levels.

Sunlight. The Olympus PEN E-PM1 struggled a little with this difficult shot, requiring more than the average amount of exposure compensation. The E-PM1 required +1.0 EV exposure compensation to keep the mannequin's face reasonably bright. Most cameras we've tested require about +0.7 EV for this "Sunlit" Portrait shot, so the E-PM1 required slightly higher than average positive compensation here. Dynamic range was limited, resulting in dark and somewhat noisy shadows, though few highlights where clipped in the white shirt and flowers. Compared to compact system cameras using APS-C sensors, the E-PM1 performed below average, though performance here was about 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-PM1 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 10.1 f-stops of total dynamic range, with 7.09 f-stops at the "High" Quality level. Roll-off at the highlight end of the curve was gradual, but for shadows it wasn't quite as well behaved. These are are average numerical results for a Micro Four Thirds sensor, though not as good as most APS-C models. Compared to the Sony NEX-C3 which uses an APS-C sensor, the E-PM1 scored quite a bit lower at the High Quality level (7.09 vs 7.84 f-stops), but scored similarly in total dynamic range (10.1 f-stops vs 10.2), though a lot of that has to do with differences in JPEG processing. Note though that this measurement has a margin of error of about 1/3 f-stop, so differences of less than 0.33 can be ignored.

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. (Slightly better results are likely possible with manually tweaking, but we weren't able to do much better.) As can be seen, the score at the highest quality level increased slightly from 7.09 to 7.45 f-stops, which is almost insignificant, while total dynamic range increased almost a full f-stop, to 11 from 10.1. Again, these results are about average for a Micro Four Thirds sensor, but not as good as most APS-C sensors. (The Sony NEX-C3 for example managed 8.74 f-stops at the highest quality level, with 11.4 f-stops total dynamic range, and higher-end NEX models do even better.) It's also 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 PEN E-PM1 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-PM1's contrast setting is quite effective and didn't impact saturation much, which is a good thing.

Gradation
Similar to dynamic range optimization systems from other manufacturers, the Olympus E-PM1'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. 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 darker midtones without making the image too flat-looking or washed-out.

Face Detection
Like most Point & Shoot cameras these days (and some DSLRs in Live View mode), the Olympus E-PM1 has the ability to detect faces, and adjust exposure and focus accordingly. The E-PM1 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. 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-PM1 performed fairly well in low lighting, capturing bright exposures at our lowest light level at all ISOs. As is often the case, the E-PM1s metering system struggled a bit with getting the exposure right at the lowest levels though, so we used manual exposure for these shots. Noise was well controlled up to ISO 800, though chroma noise is noticeable in dark shadows already at base ISO. There are a few bright pixels visible here and there at lower ISOs. (The E-PM1 does offer pixel mapping, so hot/dead pixels can be mapped out without a trip to a service center.) A lot of bright pixels (we wouldn't call them "hot") are however visible when long exposure noise reduction is turned off at lower ISOs, but they blend into the noise "grain" at ISOs above 800, where noise reduction is still active when turned "off". White balance was quite neutral using the Auto setting, just very slightly cool and magenta at most ISOs. We didn't notice any issues with banding, though some heat blooming is visible, emanating from bottom right corner at higher ISOs.

The camera's autofocus system was able to focus on our subject down to just below the 1/8 foot-candle light level unassisted with the kit lens, which is pretty good 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-PM1 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-PM1'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

Great color and detail, ISO 200 shots are good for 16x20-inch prints; ISO 1,600 shots produce a decent 11x14, and ISO 6,400 images can output a good 5x7-inch print.

ISO 200 shots are usable at 20x30, but really look better at 16x20 inches, with good color and crisp detail. A major advantage over Olympus's Micro Four Thirds rivals/partners (Panasonic) is their truer yellows, untainted by green as we still see in Panasonic MFT cameras, if not as bad as before.

ISO 400 shots also look great at 16x20 inches, though reds start to lose some detail.

ISO 800 image look very good at 13x19 inches, though some chroma noise started to show up in the shadows.

ISO 1,600 shots look good at 11x14, but blobs of chroma noise mar shadows somewhat, and the red swatch is quite a blur at this setting. Detail is good, though.

ISO 3,200 images have enough high-contrast detail for 11x14-inch prints, but color's pretty muddled, looking better at 8x10.

ISO 6,400 images are usable at 8x10, but better at 5x7.

ISO 12,800 shots are only usable at 4x6, but we wouldn't call them good thanks to the extreme degradation of detail in most solid colors.

Overall, the Olympus E-PM1 does well, though we think they could have just dropped ISO 12,800 and been just fine. These little lower-cost Olympus Pens do output some excellent color, and detail is quite good from ISO 200 to 1,600.

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.)