Olympus wasn't first to release an ultra-wide aperture portrait lens for the Micro Four Thirds system. Panasonic brought the 42.5mm Nocticron f/1.2 to market four years ago. We were wowed by the 42.5mm and gave it an Editors' Choice award, in part because of how unique an offering it was. Now it has a competitor, in the form of the Olympus M.Zuiko ED 45mm f1.2 PRO ($1,199). The Olympus is less expensive, just as impressive from an optical standpoint, and built extremely well. That makes it our new Editors' Choice.

Design

Like the other lenses in Olympus' f1.2 PRO series—the 17mm f1.2 and 25mm f1.2—the 45mm f1.2 ($1,149.00 at Amazon) is housed in a black metal barrel. It's about the same size and weight as its siblings, 3.3 by 2.8 inches (HW) and 14.5 ounces. It also uses the same filter size, 62mm, so you can use one set of filters for the entire series.

A reversible lens hood is included, as is a soft carrying pouch. The lens is sealed both internally and at the mount to protect it from dust and moisture. I shot with it in heavy snow, paired with the sealed E-M1 Mark II, and it held up like a champ. I do recommend pairing the lens with a body with a large handgrip, like the E-M1, as it's a bit heavy to use with smaller, slimmer bodies.

There's a single control button on the barrel, L-Fn, that can be set to perform different functions via your camera's menu. There's no integrated image stabilization, but both Olympus and Panasonic build that feature into Micro Four Thirds camera bodies.

Fans of manual focus will appreciate the focus clutch system. Pulling the knurled metal focus ring toward you switches the lens to manual focus. Unlike most mirrorless camera lenses, which don't offer any sort of hard stops or tactile feedback when focusing manually, the 45mm offers some amount of physical resistance when turning the ring and includes a distance scale and hard stops at both ends of its focus range. Focus is still adjusted using the motor, but the lens feels like a mechanical model. That's especially important for a portrait lens with such a wide aperture, as the design means you can make very precise adjustments to focus so you can lock in on your subject's eyes.

The lens focuses to 19.7 inches (0.5-meter), at which it captures subjects at 1:10 life-size. It's certainly not a macro lens, but you can still frame very tight headshots when shooting portraits. The Panasonic Nocticron doesn't offer an advantage or disadvantage when it comes to close focus—its minimum focus capability matches the Olympus.

Image Quality

I tested the 45mm f1.2 with the 20MP E-M1 Mark II ($1,199.00 at Amazon) . At f/1.2 it puts up very strong resolution numbers, 2,581 lines using Imatest's center-weighted sharpness test. Image quality is very strong from the center to the edge of the frame; even the extreme periphery shows 2,300 lines. Those are excellent results for a 20MP sensor; we consider 1,800 lines to be the minimum acceptable result.

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We see a very modest bump in resolution as the aperture narrows—2,635 lines at f/1.4, 2,743 lines at f/2, 2,854 lines at f/2.8, 2,818 lines at f/4, 2,797 lines at f/5.6, and 2,830 lines at f/8. At the narrowest f-stops there's a drop in resolution due to diffraction—we see 2,541 lines at f/11 and just 2,057 lines at f/16.

Olympus has described the bokeh captured by the lens (the out of focus area behind or in front of your subject) as feathered. There are a number of factors that contribute to just how the bokeh looks, including the background itself, focus distance, f-stop, and distance between the subject and background. So I tend to take any marketing claims about how the blur looks with a grain of salt. Consider the above sequence, showing how the lens draws a particular scene, as just one example. In general, I found the 45mm to draw backgrounds pleasingly.

The lens doesn't show any visible distortion, a plus for one with such a wide aperture. There is some dimness at corners when shooting wide open. We see a -1.2EV drop at f/1.2 and a -1.1EV deficit at f/1.4 when comparing the corners of an image with the center.

Conclusions

The Olympus M.Zuiko ED 45mm f1.2 PRO is an excellent performer. It combines a short telephoto angle of view, ideal for portraiture, with wide aperture optics, a weather-sealed build, and a pleasing manual focus experience. And it does it all for $400 less than its closest competition, the Panasonic Nocticron 42.5mm f/1.2 ($1,197.99 at Amazon) . All of this comes together to make the Olympus our Editors' Choice. It's not the only portrait lens available for Micro Four Thirds cameras, of course. If you're on a tighter budget, consider instead the Olympus M.Zuiko Digital ED 45mm f1.8, which doesn't gather as much light or snap images with quite as much background blur, but is priced at just $400.

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