I’m a big-screen fan. It’s the reason my primary Mac is still a 17-inch MacBook Pro, and why I have that hooked up to a 27-inch Apple Thunderbolt Display when I’m in my home office. When travelling, though, I have fewer pixels to play with. Sure, I could get a 15-inch Retina MacBook Pro, but I favor physical screen space over smaller screen elements.

There are existing apps out there, like Air Display, that let you use an iPad as a second monitor for a Mac, but they work via WiFi, which poses two problems. First, they often don’t work on WiFi hotspots, which you’re likely to be using when away from home. Second, even when they do work, there is an annoying amount of lag.

Which is where Duet comes in. Instead of using WiFi, it feeds the video signal from your Mac to iPad using a standard Lightning or 30-pin cable. Built by ex-Apple engineers, I figured it ought to be work well, so put it to the test …  expand full story