Drone - DJI out with new concept - Curt Lewis

Phantom 4 Review: DJI's New Drone Outsmarts Bad Pilots

The drone makes awesome aerial photography safer with five cameras that sense and avoid obstacles including trees, buildings and people

The new Phantom 4 drone from DJI keeps pilots from getting into crashes with computer vision that can sense and avoid obstacles including trees, buildings and people. WSJ Personal Tech columnist Geoffrey A. Fowler takes it for a test flight, including a head-on game of chicken.


The first thing I did with DJI's new Phantom 4 drone was fly straight toward a tree.

Not the best way to treat a $1,400 flying camera, sure. But this quadcopter can do something other drones can't: keep you and me from being idiot pilots.

My Phantom 4 made a beeline toward a cypress, then screeched to a halt a few feet before it. A spider-like array of cameras built into its body can see obstacles in 3-D and make split-second decisions to pause or veer to a new flight path.

After a rash of drone crashes and injuries, these flying lawn mowers needed a breakthrough. It's computer vision. The Phantom 4, arriving in Apple stores March 15, is the first consumer drone that can sense and avoid trees, buildings and moving objects. A novice can tap on an app and have it trail someone like a flying paparazzo. To put it to the test, I even challenged it to a game of chicken.

The Phantom 4 isn't foolproof-it can't see power lines or other thin obstacles, and there are no cameras in the rear, so it could back into things. Yet even in this early application of computer vision, it's the first drone I've flown that didn't make me feel like I'm one wrong move away from catastrophe.


That's important, because the broad appeal of drones isn't flying, it's the view. A drone lets anyone get over, around and through things in a way that previously required a helicopter. Up there, everything looks epic, be it your house, vacation or wedding. I've used drone selfies-"dronies"-for my last two Christmas cards.

The Phantom 4 is a creative tool, not a toy. A sleeker body and larger battery help it stay aloft over 28 minutes. A camera built into its undercarriage records lovely 4K video and 12-megapixel still shots. It's got a new wide-angle lens that's sharper in the corners than predecessors. And its video has a smooth Hollywood Steadicam look, thanks to a motorized gimbal that keeps the camera remarkably balanced, even in buffeting winds.

Not everybody was born to be a pilot, which is probably why most of my photographer friends who bought drones have ended up crashing them. (My own first dearly departed in a tree.) DJI's earlier Phantom controllers had enough dials and switches to require flight school, and demanded crackerjack spatial perception from day one. It's no wonder the Federal Aviation Administration now requires drone owners to register, or that U.S. national parks have banned the machines. (You can check which areas allow drone flights at the airmap.io website.)

The Phantom 4 simplifies flying with propellers that twist on in a way that's hard to screw up. On its front, the controller has just two joysticks, a power button and a just-land-this-thing button.

You connect your iOS or Android device via USB to the controller and use it to see, in real time, what the drone is seeing. Learning to use this while keeping your eyes on the drone in the sky definitely takes practice. A free app has extra automatic flight modes and guided tutorials, though DJI still has room to improve in helping novices sort through it all.

Operating a Phantom 4 has a lot in common with those luxury sedans that moms and dads coo over. There's serious horsepower in there: In the intimidating sports mode, it can zoom up to 45 miles an hour and rise 20 feet in a second. Yet like the latest lane-keeping and self-braking Volvo, the Phantom 4's real star is tech to save us from ourselves.

As you're getting the hang of those joysticks, the Phantom 4's new Obstacle Sensing System keeps you from getting into too much trouble. Unlike robot vacuum cleaners and autonomous cars that use laser radar to watch for obstacles, the Phantom 4 uses up to five of its optical cameras to build-and constantly update-a volumetric map of objects between 2 and 49 feet away. If they spot one, the OSS decides whether to stop and hover, or redirect the aircraft around impediments.

An autonomous function called TapFly uses four cameras to find an unobstructed path to a spot you send it to. Just tap a destination on the app screen.

The coolest and creepiest new autonomous mode is called ActiveTrack. Draw a box around people (or bikes or cars) in the app, and the Phantom 4 will keep its camera trained on them, even as they move. Unlike some other follow-me drones, the target doesn't need to carry a phone or special piece of equipment.

Running around a field with ActiveTrack on me, I felt like a Jedi, using the Force to either call the drone my way or make it jump back when I lunged toward it.

All you have to do is put your faith in the OSS. I was that guy in the park last weekend repeatedly aiming his drone at trees. I survived that game of chicken, too, though I made sure an expert pilot was in control during the test. I definitely advise not trying it at home.

There are some important limitations of the Phantom 4's OSS. Since it lacks cameras on the back and top, you could still hit a tree while flying backward or rising up into branches. The two front cameras, all that's used in regular flight, can only see obstacles in a 70-degree left-to-right field of view-basically, what's right in front.

It can't detect power lines or small branches, and if you ever want to catch a drone, use a net. (It can't see that either.) And since it relies on visible light, it only works during the day-and can get confused if it's pointed at the sun or a reflective building.

Even with those limitations, OSS on the Phantom 4 gives novices and even experienced pilots unprecedented help. This is the drone I'd recommend for any newcomer willing to spend $1,400. That is a hefty sum, considering that the Phantom 3 4K, similar in many ways except for the computer vision, costs just $800.

Some other companies, like the $550 Bebop 2 maker Parrot, focus on safety by making drones so lightweight they can be used indoors. If you did come into contact with the very fast, strong propellers on the Phantom 4, you could get hurt. In the interest of science, I stuck a hot dog in its blades, and the result wasn't pretty. I definitely wouldn't fly it indoors.

Making blades safer might limit the damage drones can inflict, but doesn't address the human error that causes crashes in the first place. Many drone makers and tech firms like Intel have said they are getting closer to sense-and-avoid drones-and even touted them in demos-but the Phantom 4 is the first consumer drone that comes with the capability out of the box. The company, one of China's largest startups, says it developed the proprietary technology itself.

DJI says it doesn't know how many smashed drones OSS might save. You still have to pay attention, but the Phantom 4's computer vision is a big step forward for keeping us out of trouble. As the technology evolves, I'm sure we'll soon think of drones less like helicopters and more like cameras.