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Duet Display turns your iPad into a second monitor

Sometimes you just need more work space on your Mac. You could appease this by buying a second monitor, but it may well be that you need this space while on traveling — a place where a second full-sized screen becomes much more cumbersome than helpful. The solution? Use your iPad.

Duet Display is a tethered second-screen option that lets you borrow your iPad's Retina display for your Mac. You can display anything you like on that second screen — including full-framerate video — and interact with that content directly on the iPad, as well.

Like Astropad, Duet Display is actually made up of two different apps, for Mac and iOS respectively. The Mac companion app is free; the iOS app is $16. Setting up Duet is dead simple: Just tether your iOS device to your Mac via Lightning or Dock connector and launch both apps, and your screen will be up and running in no time. I also appreciated how quickly Duet loads when you're reconnecting your iPad and Mac — as long as the Mac app's running in the background, when you launch the iPad version of Duet, your second screen appears almost instantly.

Duet boasts full Retina resolution on your iPad at 60FPS, and it's no joke: The screen is crisp and clear, with little-to-no possible lag. I only ran into a delay — and a millisecond one at that — when moving windows around or using Photoshop tools; contained items (like YouTube and Hulu clips) ran seamlessly and in sync with their audio, though that audio only plays on the Mac.

The iPad's touch controls are sadly a little more lacking, in part due to OS X simply not being made for fingers. One finger taps are functional enough, but two-finger scrolling is a tad jerky, and trying to work with Pixelmator brushes is downright impossible. I'm guessing it's a lag input issue, because those tasks work perfectly well when using a trackpad or mouse.

Duet is technically also usable on an iPhone — any device running iOS 7 or later, really. But the iPhone 6 and 6 Plus offer so little real estate when it comes to full-sized windows that it's hard to justify using the device for such a purpose; if an iPhone is truly your only second screen, it might be better to just use a Mountie and an app built for what you want to display.

The bottom line

Though Duet suffers somewhat when it comes to using the iPad's capacitative screen to touch and move windows, as a straight secondary display it's an excellent tool in your iPad's toolbox. I've been using it all the time alongside my MacBook Air, and it also makes a big difference in space-constrained offices where you might not have the option for a larger secondary display.

Serenity was formerly the Managing Editor at iMore, and now works for Apple. She's been talking, writing about, and tinkering with Apple products since she was old enough to double-click. In her spare time, she sketches, sings, and in her secret superhero life, plays roller derby. Follow her on Twitter @settern.

8 Comments
  • While this app is cool and works great, there is no smoothness on a iPad Gen 3 Retina. It is useable, but it isn't pretty. I need to try it on my iPad Air.
  • Works great with my late 2013 iMac and iPad Air.
  • I have an electronic piano that I write music on, it is right next to my computer desk. With all the cables on the iMac it is impractical to reposition it in proximity to the piano. With a longish cable I can use my iPad Air as a second monitor for scoring software and it works wonderfully! I tend to treat the iPad Air as a one-app second screen and Duet Display is a tremendous value to me. I like that I can switch to a different app and have iOS and then flip back to Duet Display. You can even unplug your iPad and when you plug it back in the Mac app jumps back onto the iPad as if nothing had happened. Duet Display is now mature enough to categorize it as must have, even if used infrequently. I'd pay $100 easy for it.
  • I bought AirDisplay a while ago and I found it barely useable. There was so much lag and it never ran properly. But, Duet feels like it solved all those problems. It displays great on my iPad with little lag. If you want to use your iPad as a second screen, this is the app to get.
  • agreed.. I did the same thing. AirDisplay is gone .. Duet has replaced it.. wish wireless lag issue had been solved.. but rather have it be usable..
  • Google should defiantly utilize a touchscreen for OSx Posted via the iMore App for Android
  • I downsized from a 15" MBP to a 13" a while back. I have a monitor at home and in one office but not the other office I work out of because of space limitations. AirDisplay sucked but I have been using Duet Display for a month or so now and it definitely gets my stamp of approval.
  • Come on! Lets get a real portable monitor! I am using this Gechic monitor for one year already and it is really worth the price. I really want to recommend to you guys. You can find it on AMAZON:http://amzn.to/1PFJR9U