By Joe Kashi, for the Redoubt Reporter
Given a choice, most people prefer high-quality camera systems that are small, light and highly portable. If wondering about possible trade-offs in quality, though, how does the image quality of the best new compact-system cameras compare with the best midrange digital SLR cameras using larger APS-C sensors? Surprisingly well.
As a sequel to our recent discussions of current dSLR cameras, this week we’ll directly compare Pentax’s K-5 and the new Olympus OM-D. (Also termed the E-M5 by Olympus. Don’t ask me why.) They’re among the best, if not the best, camera systems in their respective categories.
Even though it’s a 2010 design, there’s a consensus that Pentax’s K-5 dSLR has some of the best potential image quality of any currently available camera using a standard APS-C sensor. In fact, when used with excellent lenses and good technique, enlarged images made with a K-5 approach the quality of images made with many full-frame cameras.
Similarly, Olympus’ recently introduced 16-megapixel OM-D is, by general consensus, one of the two or three best currently available compact-system cameras. In the near future, Panasonic will likely announce a prolevel Micro Four-Thirds camera that rivals the OM-D. However, at this time, there’s nothing tangible from Panasonic that’s directly comparable to the OM-D in practice, or even as paper specifications.
Fujifilm’s 16-megapixel X-Pro1 and Sony’s 24-megapixel NEX-7, both APS-C compact-system cameras, can provide excellent quality images that, under the right circumstances, are quite comparable to the OM-D. However, both the Fujifilm and Sony systems are significantly hampered by the limited number of top-end lenses available for those unique lens mounts. The Micro Four-Thirds system shared by Olympus and Panasonic, on the other hand, has an abundance of fairly priced, excellent lenses. In the end, I found, excellent optics are the single most important factor affecting optimum image quality.
Both the Fujifilm X-Pro1 system and Sony’s NEX-7 are also hampered by the lack of image stabilization when used with most lenses. That lack of any image stabilization is a real deal-breaker for many knowledgeable photographers.
Image stabilization is probably the most useful secondary innovation that accompanied digital photography. Effective image stabilization hardware allows you to use lower shutter speeds and, thus, lower ISO sensitivities where image quality is best. As an example, that means you can use ISO 200 in situations where unstabilized cameras must use ISO 1,600 to ISO 3,200 to avoid camera shake. Thus, effective stabilization is a major image quality advantage, more useful in many situations than using a larger sensor, at least with subjects that are not moving quickly.
Olympus’ OM-D uses a unique and highly effective image-stabilization system — the sensor itself is suspended in a magnetic field that almost instantly corrects for shake and rotation on five axes: the usual left-right X axis, the up-down Y axis, and three rotational directions. To my knowledge, no other camera corrects for image blurring caused by rotation. As a result, the OM-D can effectively correct for a great deal of complex camera shake, even at very slow shutter speeds.
Another important advantage of current Olympus cameras is that vendor’s very fast and accurate “contrast detection” autofocus system. Digital SLR cameras generally use “phase detection” autofocus hardware, which requires a separate focus sensor in the viewfinder. Until recently, phase detection autofocus was preferred because it was noticeably faster. However, the accuracy of phase detection focus is critically dependent on near-perfect assembly and calibration of that autofocus hardware. As a result, phase detection autofocus hardware is very susceptible to misalignment in manufacture and to later jarring.
Generally, compact-system cameras like the OM-D use a different sort of autofocus mechanism, “contrast detection,” which works directly with the sensor’s image. In theory, contrast detection autofocus is simpler, more rugged and more accurate. Until recently, though, contrast detection autofocus was too slow. Both Olympus and Panasonic have solved that limitation by introducing contrast detection hardware that’s as fast or faster than dSLR cameras.
I’ve made a series of test images pitting the OM-D against the K-5.
Test procedure: I believe that comparative tests are most meaningful when they approximate our daily technique. For that reason, all images were shot handheld as RAW image files at each lens’ optimum aperture and at the camera’s base ISO, unless otherwise noted. I later individually corrected each image in Adobe Lightroom to extract the best possible quality from each image. Generally, our crops were taken from the corners and edges of each image frame because most lenses, especially less-expensive ones, suffer lower image quality most noticeably near the edges. All exposures were handheld because, realistically, that’s how most of us take the great majority of our photos.
I used Olympus’ 50-mm f/2 macro lens for some Micro Four-Thirds images and Pentax’s 100-mm f/2.8 WR macro lens on the K-5. Both of these lenses are considered to be among the sharpest currently available
lenses and are reasonably comparable, taking into account sensor crop factors and subject size. They bring out the best in their respective cameras.
Conclusions:Until now, only a few dSLR cameras could produce excellent quality images at ISO 3,200. Of those, the K-5 is considered to be among the best low-light, high-ISO midrange dSLR cameras. Yet, as you can see from the split image immediately below, the Olympus OM-D detail on the right is sharper than the equivalent K-5 detail on the left. Both images were shot handheld from about 8 feet under low indoor light. Why did that surprising result occur?
There are several likely reasons why the OM-D did a better job than the larger K-5 in this ISO 3,200 test. Among the most significant reasons, in my opinion, are the excellent image quality of the newer 16-megapixel Sony sensor in the OM-D and the exceptional sharpness of Olympus’ 50-mm f/2 lens (about $500). Another likely reason is the very sophisticated and effective five-axis image stabilization hardware built into the OM-D itself that eliminated camera shake in this handheld, low-light photo. Finally, it’s likely that the OM-D’s contrast detection autofocus is more accurate, an expected result. The Pentax 100-mm f/2.8 WR lens is also quite an excellent lens, but the Olympus body and 50-mm lens combination was simply sharper here.
My other Olympus camera, a 2011 E-P3, uses an older, noisier Panasonic 12-megapixel sensor and a
less-effective image stabilization system. Despite those hardware limitations, the E-P3 surprisingly did nearly as well as the OM-D at ISO 3,200 when used with the 50-mm f/2 lens. This suggests that the exceptional quality of the Olympus 50-mm is one major factor, and also that I need to recalibrate the phase detection autofocus on my dSLR using my Lens-Align focus tool.
- Both the OM-D and the K-5 show virtually no image noise when used between base ISO 200 and ISO 800. ISO 800 images are virtually indistinguishable in both cases except for a slight softening of fine detail and slightly lower crispness at ISO 800. That’s an excellent result for both cameras.
- I also compared my Olympus 50-mm prime lens with the two kit zoom lenses available with the OM-D and the E-P3. Olympus’ more recent, weather-sealed, 12- to 50-mm kit lens is intended as the principal kit zoom lens for the weather-sealed OM-D, while the 14- to 42-mm II unsealed lens is available with both the OM-D and the E-P3. I tested all three lenses at their optimum apertures, f/5.6 for the 50-mm prime lens and f/8 at maximum magnification for both kit zoom lenses. As expected, the 50-mm f/2 prime lens was noticeably sharper, especially along the edges, but both Olympus kit zoom lenses did surprisingly well.
The major difference was that images made with the kit zoom lenses did not appear to be quite as crisp. I found that the sometimes-maligned 12- to 50-mm zoom is
definitely sharper and shows better image contrast than the earlier, less-expensive 14- to 42-mm II kit lens, itself a better-than-average kit zoom. The 12- to 50-mm lens’ superior sharpness is mostly visible as a lack of fine detail but, as comparative photos posted at our website show, it’s not a major difference.
- The newer 12- to 50-mm kit zoom lens has surprisingly good macro capabilities, but the 50-mm prime macro lens was, as expected, definitely sharper at very close distances. Although the 12- to 50-mm lens may show chromatic aberration at some settings, that’s easy to fix in Lightroom 4.1. Just check the develop module box labeled “fix chromatic aberration.”
- I’ve been resistant to touch-screen shooting for a long time but I changed my mind after using the OM-D’s touch screen, which is easy to turn on and off. Just touch the point where the camera should
focus and the OM-D will focus, calculate exposure and take the image. It’s very handy.
- The OM-D has an excellent nine-frames-per-second top speed in bright light. That’s good enough for most outdoor sports photography, particularly because the autofocus is so fast. I also found that the OM-D has very good dynamic range. Overly bright highlights and dark shadow areas correct easily and effectively in Lightroom 4.1.
Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. He has published many articles about computer technology, law practice and digital photography in national media since 1990. Many of his technology and photography articles can be accessed through his website, http://www.kashilaw.com.
Redoubt Reporter Summer photo contest
It’s time for the third Redoubt Reporter, reader-submitted photo contest.
Photos will be judged and winners selected by a three-member panel. After each contest closes, we’ll publish and discuss some of our favorites in the Redoubt Reporter, space permitting. Some of the selected photographers will be invited to frame and hang their photos at a Redoubt Reporter June 2013 group photo show scheduled at the Sterling Highway Kaladi Brothers coffee shop.
The deadline to enter is 11:59 p.m. Aug. 31, 2012. All submissions must be in high-quality digital format. Submit no more than five JPEG images by email to email@example.com.
1. Our theme is “Summer on the Kenai” and submissions must fit this theme. Summer is always interesting here in Alaska, with a vast number of photos taken. We encourage you to submit photos of what you observed over the summer. As always, we prefer photos that are fresh and unique. Frequently photographed subjects, like combat fishing, should be avoided.
2. Entrants must be amateur photographers who are residents of the central Kenai Peninsula.
3. Photographs can be of any subject fitting the theme but must have been taken of the Kenai Peninsula on or after June 1, 2012.
4. If you submit photographs in which people are recognizable, you must also provide us with their permission for us to publish any such photographs.
5. Please do not submit portrait photos. Do not submit photographs whose content would not be appropriate for publication in a family newspaper. Do not submit photos of illegal subject matter. All such photos will be deleted immediately without notice to you and at the sole discretion of the editor.
6. Photographers must include their name, telephone number, email address, town of residency and each photo’s date, location and description of subject matter.
7. Submitted JPEG images should be of the best possible technical quality. Good technique and technical quality are important, but originality, creativity, interesting subject matter, artistic merit and good composition are even more important.
8. By submitting photos, you agree to our publication of them in the Redoubt Reporter newspaper and on our website. The Redoubt Reporter will have the right of first publication of your photos. However, you will retain the copyright for all other purposes and your name will be listed if we publish any of your photos.
9. Our decisions about what’s published or selected for exhibition are final and are admittedly subjective. Space is limited, and the judging panel and editor reserve the right to choose photos at their discretion.
10. Retain your original digital files of all submitted images. We are not responsible for preserving copies of your digital images.