As the smallest, lightest, and lowest cost lens in the series, the Olympus M.Zuiko Digital ED 12-45mm F4 Pro ($649.99) is an enticing new entry in the well-established Micro Four Thirds system. It's one that gets most things right, from size and build quality to imaging capabilities. It's a fine alternative to the M.Zuiko 12-40mm F2.8 Pro for less money, and the lens to get if you don't do a lot of low-light photography, earning our Editors' Choice.

Compact Standard Zoom

The 12-45mm F4 covers a standard angle, about the same as a 24-90mm on a full-frame sensor. For many photographers, it means it will be the zoom that spends the most time of any lens on your camera.

It's small for a zoom, measuring just 2.8 by 2.5 inches (HD) and adding a mere 9 ounces to your camera. The outer barrel is metal, while an inner polycarbonate tube extends when the lens is zoomed in. It supports 58mm front filters and includes a reversible, petal-style lens hood.

As part of Olympus' Pro series, the design incorporates dust and splash protection; it doesn't have an official IP rating, like recent cameras, but will have no problem surviving a downpour when paired with an E-M5 or E-M1 series body.

The zoom ring takes up much of the barrel and has a textured, knurled metal finish. It takes about a 90-degree turn to move from 12 to 45mm.

It's joined by a narrower ring for manual focus control—it works well, turning with a little bit of resistance for smooth, precise manual control. It doesn't have quite the same feel as the manual focus clutch you get with the 12-40mm F2.8, but it's not too far off.

Autofocus is speedy and silent. The lens isn't stabilized, but Olympus puts the feature into all of its current cameras, so you won't miss it. There's almost no visible change in the angle of view, an effect called focus breathing, at the wide end, and only a slight one when zoomed in. That means videographers can use the lens for shots where the plane of focus changes, without worry viewers will be taken out of the moment due to the change in framing.

If you prioritize handheld video recording, you should think about a lens that adds its own stabilization to the mix; the 12-100mm F4 is larger and pricier, but offers class-leading stabilization when paired with an E-M1 Mark II or Mark III.

The lens focuses quite close, to just 4.7 inches from the sensor plane, good enough for 1:4 macro reproduction when zoomed all the way in. You'll have no problem getting close-up shots—this is a lens that lets you lean in to get closer, not one that requires you to back away from your subject to get a shot.

In the Lab

I tested the 12-45mm along with the 20MP E-M1 Mark III and software from Imatest. An analysis of an SFRplus chart shows the zoom to be a strong performer across its entire zoom range.

At 12mm f/4, it delivers 2,440 lines on a center-weighted evaluation, a result that's considered excellent for the camera. There's a slight drop in clarity at the edges of the frame, but they're still solid (2,000 lines).

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The average ticks up at f/5.6 (2,475 lines), with very good edge clarity (2,165 lines). It holds pretty steady at f/8 (2,380 lines) and f/11 (2,295 lines), but does drop a bit at f/16 (1,865 lines) and f/22 (1,250 lines). I'd still use f/16 if you want to get defined sunstars in your landscape shots, though don't expect the same pinpoint look you get from wide angle primes and zooms.

At 25mm resolution ticks up, and edges show as much detail as the center. We see an outstanding 2,850 lines at f/4 and f/5.6, and excellent results at f/8 (2,580 lines) and f/11 (2,400 lines). Resolution drops a bit at f/16 (1,950 lines), and more so at f/22 (1,300 lines).

Image quality is also excellent at the maximum 45mm zoom setting. The lens delivers 2,505 lines at f/4, and improves to an outstanding 2,715 lines at f/5.6. It holds its own at narrower f-stops, settling in around 2,350 lines at f/8 through f/11, but you should still skip f/16 (1,870 lines) and f/22 (1,275 lines) for most shots.

Neither JPG images or Lightroom-processed Raw photos show any visible signs of distortion. Likewise, illumination is fairly even from center to corner, so there's only a faint vignette visible when shooting at 12mm f/4.

If there's a complaint to be made about the optics, it's that the lens is an f/4 design. That means it captures just about half the light as a lens with an f/2.8 aperture, so you'll need to push your camera ISO a little higher when working in dim light versus the 12-40mm F2.8 Pro, and you won't have quite as shallow a depth of field in many images when the iris is opened all the way.

Upgrade Your Zoom

Photographers using the Micro Four Thirds camera system have loads of lens options to choose from. It's not just supported by Olympus—Panasonic makes cameras and lenses too, and there's plenty of third-party support as well.

Even with alternatives, if you're looking to upgrade your starter zoom, or simply looking for a lightweight, all-weather lens for travel and walks about town, it's tough to beat the 12-45mm F4 Pro. It's got more wide angle coverage than the inexpensive 14-42mm EZ F3.5-5.6 bundled with many Olympus cameras, and the premium fit and finish that enthusiast photographers are after.

There are a couple of other zooms to think about, including the 12-100mm F4 Pro—it costs twice as much, but also zooms in further. Event and wedding photographers will want to look for the shorter, but brighter, 12-40mm F2.8 Pro for $1,000.

But if you're shopping on a budget, or prioritizing size and weight above all, the 12-45mm F4 Pro is the lens to get, and our Editors' Choice. You won't find a better standard zoom for a Micro Four Thirds camera for this price or less.