Olympus didn't invent the smartphone add-on camera—Sony was first to market with the QX100 ($199.99 at Amazon) and QX10 ($131.65 at Amazon) —but it is attempting to refine the concept with the AIR A01 ($299.99, body only). The small Micro Four Thirds mirrorless camera does make some refinements to the concept, and there are some applications for which it's appealing, but it is ergonomically unsound for handheld shooting. If you're just in the market for an inexpensive mirrorless camera, you're better off with another Olympus option, our Editors' Choice, the Olympus PEN E-PL6 ($394.42 at Amazon) .

Design
The AIR A01 ($448.00 at Amazon)  is a small cylinder that measures 1.7 by 2.2 inches (HD) and weighs about 5.2 ounces. It's compatible with Micro Four Thirds lenses—we're reviewing it as a body only, but a kit option is available with the M.Zuiko ED 14-42mm f3.5-5.6 EZ ($224.00 at Amazon) for $499.99. The AIR is available in a black or white finish.

The normal array of things you'd expect to see on a camera—an LCD, control dials and switches, and an ergonomic handgrip—are missing. Instead you just get a power button on top, along with a large shutter release control and a status indicator light. A removable smartphone mount at the rear can be adjusted to work with small or large phones—it had no problem fitting an iPhone 6 Plus ($299.00 at Verizon Wireless) with a case.

The mount can be tricky to remove—you'll need to twist it while holding down a catch release on the body. But once it's off you have access to the micro USB port (for data transfer and for charging of the internal, non-removable battery), and the toggle switch to turn the AIR's Wi-Fi on or off (useful if you plan on using it on an airplane or other areas where Wi-Fi is verboten). There's an additional plastic cover you'll need to remove in order to access the microSD memory card slot.

Holding the AIR with a phone attached is not exactly comfortable. Even when paired with a small prime lens, the camera is a little cumbersome to hold. I used the M.Zuiko 12mm f2 ($849.98 at Amazon) and M.Zuiko 25mm f1.8 ($299.00 at Amazon) during testing. With both lenses I wasn't quite sure whether to hold the AIR by its body, or to hold onto my phone; I ultimately found my grip to be more secure when holding onto the AIR's cylindrical body. It's easier to access on-screen controls when holding onto the phone, but I was always worried about the clip giving way and the AIR falling to the ground when using this method, as it's notably heavier than a smartphone with a lens attached. Those fears proved unfounded, but it doesn't change the fact that the AIR is simply awkward to use as a handheld device.

There is a standard tripod mount, of course. And if you were thinking about the AIR as a small, inconspicuous camera you can squeeze into a tight spot for remote operation, it's capable. There is some shutter lag when operating it remotely, so it may take some trial and error to get the perfect shot if you're thinking about mounting the camera in a backyard bird feeder or other spot where your subjects would be disturbed by a visible human presence.

App
The AIR is best used when paired with its companion app, O.A. Central. Available for Android and iOS, the app connects to the camera via Wi-Fi, streaming a live feed to your phone or tablet's screen. Pairing via Wi-Fi is simple, though if you're already connected to another network, you'll need to manually connect to the AIR's network each time you use it. (This is par for the course with camera Wi-Fi.) The AIR A01 does have Bluetooth, which can wake it from sleep on demand, though you'll still need to manually switch the Wi-Fi network.

Once everything is connected and communicating, you'll need to choose the mode in which you want to shoot. There are six: Mode Dial, Art Filter, Color Creator, Photo Story, Clips, and Genius. Mode Dial supports traditional camera operation, with control over shutter speed, aperture, and ISO. 

Filters are built into current Olympus cameras, including the midrange E-M10 Mark II ($300.00 at Amazon) , and act just like the ones you find on Instagram—you can capture images with vivid colors, in sepia tones, with a cross-processed look, in black-and-white, and so on. The Color Creator mode is a bit more targeted—it allows you to tune the standard color output to better suit your taste.

Photo Story is used to create multi-image collages in-camera. These can be saved in a square format that's ideal for Instagram . Clips is where you'll want to go if you plan on doing any video work that requires editing. You can record video from the standard Mode Dial screen, but Clips adds the ability to assemble short shots into a longer movie.

Finally there's Genius. It's basically a copy of the Creative Shot feature that Canon puts in many of its PowerShot cameras, like the G5 X ($699.00 at Walmart) . The AIR captures seven photos—your original, as well as six images with varying crops and filters. If you don't mind shooting in JPG—Raw isn't supported in this mode—it's a fun way to snap some photos with a creative look.

The app isn't without issues. One of note that I ran into during testing—when working with a lens like the Olympus 12mm f/2 that includes a focus clutch system, the AIR had a hard time dealing with switching back and forth between manual and autofocus. Autofocus would regularly stop working, even if the focus clutch was in the autofocus position. I had to put the AIR to sleep and kill the app in order to get autofocus working again.

I also had some problems connecting in areas with lots of Wi-Fi signals and activities. When I was out in a park there was no lag in connection and I was able to hold the phone in one hand and the AIR in another without issue. But in a Manhattan office building the phone needed to be attached to the camera in order to work, and even then there was some choppiness in the video feed.

Performance and Image Quality
Using the phone to control the AIR A01 introduces some slowness. There's a 0.4-second lag between tapping the on-screen shutter button and the AIR capturing an image. If you opt to use the physical shutter button the delay is cut to 0.1-second, the time the camera requires to confirm focus and capture an image. That's on par with other mirrorless cameras. The insanely small Panasonic GM1 ($660.00 at Amazon) , for instance, also requires about 0.1-second to confirm focus and fire.

In terms of burst shooting, the AIR A01 can fire off shots at about 10fps in continuous drive mode. But it's limited as to how many images it can capture at that pace. When shooting Raw+JPG the buffer fills after 9 shots, with the camera slowing considerably to less than 3fps after that. In JPG mode you'll get 11 shots, and the camera doesn't slow down as much—it settles into shooting at about 5.5fps after the initial speed burst and can keep that up for some time.

See How We Test Digital Cameras

I used Imatest to look at how the AIR's 16-megapixel image sensor stands up to capturing photos at high ISOs. If you're comparing it with your smartphone's sensor, the AIR will absolutely blow it away in terms of detail and noise control. Imatest indicates that the camera controls noise well, keeping it under 1.5 percent through ISO 6400 when shooting JPGs. A close look at photos from our ISO test scene shows that fine detail does take a hit at ISO 6400. But it holds up well at ISO 3200 and ISO 1600, and at ISO 800 is just as good as the Raw output. These are solid results for a mirrorless camera. I did use the highest quality JPG setting for our tests; by default the AIR is set to a more aggressive compression rate, so you'll want to venture into the settings and switch to Xtra Fine to get the best JPG output possible.

Raw capture is also an option, and it allows you to squeeze more information out of images at higher ISO settings. Raw images retain fine detail even at ISO 6400—although there is a grainy quality to photos when you push the camera that far. ISO 12800 is useable, if you don't mind a grainy image—Raw photos are much sharper than JPGs captured at the camera's top ISO sensitivity.

The top video quality is a little limited—1080p30 was the cat's meow a few years ago, but now many mirrorless cameras offer the option to push the frame rate to 60fps or the resolution to 4K. The footage, saved in QuickTime format, is crisp and smooth. The AF system reacts promptly to changes in the scene and changes focus with a pleasant, slow rack. Audio is clear when recorded close, but the internal mic does pick up a lot of background noise and you can't add an external one.

The real complaint is that, since the AIR lacks in-body stabilization, handheld video has a jittery look. You can use a stabilized lens, but your options are limited on the Olympus side of the fence, as most of its cameras put stabilization into the body. Panasonic lenses, which work fine with the AIR, do often have stabilization, and should be a preference if you're keen on shooting steady handheld video.

Conclusions
The Olympus AIR A01 is another attempt to create a digital camera that works in conjunction with a smartphone to achieve its fullest potential. But, like other devices of this type, including the similar Sony QX series and the tiny DxO One ($199.95 at Amazon) , it has some issues. The AIR's are mainly ergonomic, although its companion app exhibited behavior that was occasionally quirky. There are conventional cameras available for around the same price that deliver similar image quality and a more pleasant design for handheld use. The Olympus PEN E-PL6 is our Editors' Choice for budget mirrorless compacts—it costs the same with a bundled lens as the AIR A01 does without. If you want something really small, you should also take a gander at the Panasonic GM1. It uses the same Micro Four Thirds lens system and a similar image sensor, and costs about $400 with a bundled zoom lens.

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