Olympus OM-D E-M5 Digital Camera Review
While Olympus' PEN series of mirrorless cameras has always offered superb color rendition, they've generally struggled to keep noise down at the higher ISOs. The OM-D E-M5 seems to have similar problems, but the higher ISO speeds don't suffer from the same runaway noise problems that plagued earlier Olympus sensors. If you plan to go above ISO 1600, though, we recommend turning on noise reduction at some level. More on how we test noise.
The Olympus OM-D E-M5 features an ISO range that extends from 200-25600 when extended. The sensor's native ISO range is 200-1600, which is where the noise performance is acceptable without having to resort to noise reduction. You can set ISO through the main menu, through the control panel, or via the on-screen guide that pops up when you press the OK button.
Focus on the Olympus OM-D E-M5 is lightning quick, even faster than we saw on the latest series of PEN cameras. It's also startlingly accurate for a contrast detection system. Contrast detection systems, by their nature, have to move past optimal focus in order to ensure maximum sharpness, retreating to the point of highest contrast. That the camera can do so that fast is remarkable, and it gives the E-M5 a leg up on the rest of its competition in the high-end compact system camera market.
Video: Low Light Sensitivity
While the Olympus E-M5's 16-megapixel sensor did well in most of our video tests, in the end it is still physically smaller than the APS-C sensors that its competitors have, hindering its low light sensitivity. Still, compared to its mirrorless competition, it didn't fare too poorly. With ISO on automatic (capped by the camera at ISO 3200), we found the E-M5 needed 18 lux of light to render an image that reached 50 IRE on a waveform monitor (about what would be acceptably bright when viewed on a television). This is actually right in line with the Sony Alpha NEX-7, which needed 17 lux to get a similar result.