The OM-D E-M1 is the best mirrorless camera ever from Olympus, and it's attracting interest from serious photographers who had, up until now, ignored Olympus and Micro Four Thirds technology. But the E-M1 deserves all the attention--it's the new champ in the "lightweight heavyweight" class.

The E-M1's sturdy magnesium body is splash and dust resistant, and freeze resistant down to 14º F (-10º C). At 1.1 pounds with a battery and SD card, it's lightweight compared to, say, a full-frame Sony A99 (1.8 pounds). And while not tiny, it's not a lot bigger than my iPhone 5 in its Otterbox case.

The E-M1's electronic viewfinder (EVF) is the best I've ever used, with 2.3 million dots providing 100 percent coverage at a stunning 1.4x magnification. At 21mm, the eye-point is high enough to allow me to shoot while wearing glasses. And it doesn't suffer from the high-contrast problem I reported when I reviewed the Sony Alpha SLT-A77.

The E-M1's body is packed with buttons and levers and switches, yet everything makes sense and the design is not busy. Atop the power switch on the left you'll find two buttons that, by default, control focus options and HDR or bracketing. On the right side of the camera are front and rear dials for aperture and shutter that, to me, are placed exactly right, along with the mode dial (now with a locking button), and two function buttons. The default uses of the buttons make sense and you can certainly start shooting immediately, but practically everything can be reconfigured to suit your preferences. The Fn1 button, which I've set up for ISO, sits directly under my thumb. I can find every button on the outside of the E-M1 without hesitation and without having to take my eye from the EVF.

One do-hickey on the back of the E-M1 deserves special mention: the two-position lever. By default, it changes the functions of the front and rear control dials. But it's highly configurable, like almost everything else on the camera. I have repurposed it to toggle between autofocus and manual focus.

The E-M1 comes with a small detachable flash. I use it only for optical triggering of several Olympus FL-600R flashes. The E-M1 lets me control groups of remote flashes from the back of the camera.

And how fast is the E-M1? Max shutter speed 1/8000th of a second. Max sync speed for flash: 1/320th second. Max continuous shooting speed: 10 fps. It's fast.

Shooting stills

Do your job right as photographer, and the E-M1 will deliver images that do not disappoint. Automatic exposure is on target, if a bit conservative. Color is accurate and well saturated. I recommend shooting raw for maximum flexibility, and the E-M1's ORF raw files give you lots to work with. But thanks to the TruePic VII image processor, in-camera JPEGs are quite good, with automatic correction of lens distortion and chromatic aberration. I continue to use DxO Optics Pro 9 to make these adjustments to raw files on my computer, but I'm starting to wonder if I'm not doing things the hard way.

Like other Micro Four-Thirds cameras, the E-M1's sensor has a resolution of 16 megapixels: small enough to keep a lid on noise, large enough for oversized prints. By eliminating the optical low-pass (anti-aliasing) filter, the E-M1's sensor should, in theory, generate images with finer detail. I can't tell if it's the lack of the anti-aliasing or the excellence of the lenses I've tested it with, but the E-M1 can deliver tack sharp shots.

The ISO dial goes up to 25,600. As with every other camera ever made, noise increases with ISO. But between particularly between ISO 200 and 3200, with proper exposure, the E-M1 will deliver images that are as good as those from any APS-C camera today and that often rival images from full-frame cameras.

The E-M1 is helped enormously by best in-body image stabilization (IBIS) around. Olympus's five-axis sensor shift IS technology adjusts not just for up-down or side-to-side camera shake but for rotation on three other axes, and it's very effective. IBIS helps every lens you use on the camera and on a mirrorless camera like the E-M1, IBIS stabilizes the image while you're composing the shot.

The E-M1's Dual FAST autofocus system combines on-chip phase detection autofocus with contrast detect autofocus for responsive, accurate autofocus. You can target focus on 81 (9-by-9) points, available almost anywhere in the frame. Touching one of the buttons on the four-way controller instantly moves the focus target, something I found disconcerting at first, but now regard as brilliant. On the other hand, when I'm shooting with the camera on a tripod, I find myself increasingly using the touch-screen to focus on the rear monitor. While I'm talking about autofocus, I have to mention the E-M1's remarkable eye-priority face detection. I've not had good luck with face detection autofocus in the past, but the E-M1's system is scary good.

I still use manual focus fairly often, and high-tech innovations like focus magnification and focus peaking make old-school focusing easy and reliable. You can configure the camera to magnify the image automatically when you turn the focus ring of the lens, but I find that intrusive, so I invoke magnification by tapping a button on the front of the camera under the lens mount, which is within easy reach of the ring finger on my right hand.

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