How Can I use My iMac as a Second Monitor?

Because of the Coronavirus I have been working from home on a tentative basis most of this week. I have a feeling that will be permanent starting next week.

My work computer is a 2019 15-inch Macbook Pro.

I have a 2017 iMac at home.

The newer iMacs no longer support target display mode, which allows them to function as a second screen. Is there any way I can use my home iMac as a second monitor?

Most of the posts I searched for were about turning old iMacs into monitors using Target Display Mode. However, a little more digging surfaced two interesting options:

  • Luna Display has a USB-C hardware dongle
  • Duet looks to be a software solution.

Think I’m leaning towards the Luna. Perhaps, I can get it expensed?

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Curious what the lag is like for each of those. If it is bad, that could be really annoying.

Certainly the software only one is slower?

Well, I’ve ordered the Luna Display.

I will let you know soon!

I’ve also realized that if the Luna Display works as advertised, I’ll need to get a new keyboard that will allow me to switch between my iMac and Macbook Pro. I think Logitech’s new MX Keys Keyboard has the same quick switch function as the MX Master mice.

What happened with this? Did the fob work?

Well, the short answer is yes, but there are several caveats. Nothing comes close to the ease of Target Display Mode found in the pre-5k models.

The Luna Display can turn your iMac into a second monitor.

It will also use the iMac’s keyboard and mouse—it’s pretty cool. There’s very little latency between movements, which was a concern of mine.

However, there are a handful of caveats:

  • The iMac doesn’t have 5k resolution
  • I can’t mouse over to my Macbook pro

If I was mostly doing development, or worked in spreadsheets or was anything other than a designer, I think the Luna Display would be a fine solution. I absolutely need retina resolution to make it worthwhile though.

I’d probably grab the MX Keys and an MX Master 3 and just use the pairing switch to toggle between the iMac and Macbook pro.