If you own an iPad and an Apple Pencil, there are several ways to pair them with your computer and transform them into a high-quality pen display for photo editing. There’s Apple’s own Sidecar feature, the popular app Astropad, the hardware-assisted option Luna Display, and the “made by ex-Apple engineers” Duet Pro. I wanted to see which of these options offers the most features and the best experience for the photographer on the go.
Not that long ago, editing your photos with a pressure-sensitive pen on a high-resolution display meant shelling out thousands of dollars for one of Wacom’s Cintiq Pro products. Even now, with more affordable, lower-resolution options available from Wacom and several of its competitors, you’re still coughing up a significant amount of cash for a unitasker of a product that is often too bulky and inconvenient to take with you to a coffee shop or set up on the tray table in an airplane.
From that perspective, an iPad feels like the perfect alternative. It’s small, it’s lightweight, it boasts a high-resolution screen with good color accuracy, and it offers a great pen experience thanks to the Apple Pencil.
The question is: how do you do it? If you’re a Mac user, is Apple’s built-in Sidecar feature good enough? What about PC users, what can they use? And is Luna Display—the only option that uses a hardware dongle to “trick” your computer into thinking the iPad is a true blue second screen—miles better than the competition? We got our hands on all four options to find out.
When Apple introduced Sidecar in June of 2019, a lot of people watching thought it was the end of third-party options like Astropad and Luna Display. Why would you pay someone else for a feature Apple was now including free of charge? As it turns out, there are a few good reasons why you might want to do just that.
Firstly, if you’re a Windows user, Sidecar is out by default — the feature is only available on Mac.
Secondly, you need a relatively new iPad and a relatively new Mac in order to make it work… something I found out the hard way when I wanted to try Sidecar on my mid-2015 Retina MacBook Pro. You need a MacBook Pro released in 2016 or newer, a MacBook Air released in 2018 or newer, or an iMac released in late 2015 or newer. You also need an iPad Pro, a third-generation iPad Air, a fifth-generation iPad Mini, or a regular iPad that’s six-generation or later. You can find a full breakdown of compatible hardware here.
Finally, while Apple did nail the basics with Sidecar, as you might expect, they locked it down pretty tightly after that. The shortcut keys on the sidebar can’t be modified, there is no control over pen pressure curves, you can’t program your own shortcuts, and there are only a few basic gestures for pinch, swipe, and zoom. True, the iPadOS text editing gestures for undo and redo aren’t limited to text, but they’re not well suited for photo editing: both are three-finger swiping gestures, so when I tried to use them in Photoshop, I ended up sending my canvas off-screen by accident at least 50 percent of the time.
If these things aren’t deal-breakers, Sidecar is admittedly a pretty sweet deal. After all, it is free, and since it’s a part of Apple’s walled garden it performs flawlessly whether you’re plugged in or connecting over WiFi. In fact, of the options I tested, it’s the most stable over wireless. It’s just limited by Apple, for Apple, and that’s going to be a pain if you really want to customize your photo editing experience with additional shortcuts, advanced multi-touch gestures, or other useful features like pen pressure curves.
Astropad is the maker of two of today’s third-party alternatives. There’s Luna Display, which we’ll talk about in a second, and the company’s namesake app Astropad.
Astropad works just like Sidecar. There is no hardware dongle necessary: just download the Astropad app on the Mac and on your iPad, and you can connect over WiFi or over a USB cable. As of March, you can also download the public beta of Astropad for Windows, code-named Project Blue, which makes this our first cross-platform option.
Unlike Sidecar, Astropad is not free. You can pick up Astropad Standard for a one-time fee of $30, or Astropad Studio (which is what we were testing) for $80 per year or $12 per month.
This is very much a “good news, bad news” situation. The good news is that Astropad includes a ton of additional gestures, unlimited shortcut sets that can be customized by app, the ability to create custom pressure curves, and much much more, all incredibly useful and user-friendly. The bad news is that you’ll have to subscribe to Astropad Studio to get most of these benefits.
Astropad Standard lacks pressure curve customization, support for unlimited shortcut sets, “Magic Gestures,” on-screen keyboard, and external keyboard support.
Losing Magic Gestures is particularly painful because they’re so useful. These gestures allow you to set one, two, and three-finger taps (and holds) to various useful shortcuts like Undo, Redo, Eraser, and “Hover”—an extremely useful feature that lets you move the mouse around with your pencil without activating the click at the same time.
Both versions use the same intuitive user-friendly UI with useful shortcuts that change based on your app, and both use the same tech to connect over WiFi or wired in over USB. Wired in, the latency is rock solid at three to six milliseconds. Over WiFi, it ranged from a best of nine milliseconds to a max of over 150 milliseconds when the connection faltered or there was a lot going on. The average danced around 30 to 50 milliseconds, jumping up to slower speeds when you tried something new and then settling in between 10 and 15 milliseconds whenever there was less action on the screen.
Neither version can be used as a secondary display: even if you shell out for the Studio version, you can only mirror your display.
Finally, both versions of the app are more broadly compatible than Sidecar. Astropad works with any Mac running MacOS 10.11 El Capitan or newer and allows you to use slightly older iPad hardware as well.
In short: Astropad Studio is leaps and bounds better than Sidecar, with way more customizations and the best UI of the bunch. But at $12 per month or $80 per year, these benefits come at a steep price. Astropad Standard, meanwhile, is a hard sell unless you have an older Mac that isn’t compatible with Apple Sidecar. I do still like the UI better than Sidecar, but without the useful Magic Gestures and/or the ability to create customized shortcuts for various apps, I’m not sure it’s worth the $30.
Also made by the folks at Astropad, Luna Display is the only option on our list that uses a hardware dongle instead of relying exclusively on WiFi or a USB connection. It’s been available for Mac for some time now — in USB-C and MiniDisplay Port variants — and is currently available for pre-order for Windows as USB-C or HDMI.
On the one hand, this allows Luna to “trick” your computer into thinking it’s using a real, secondary display. The dongle receives a display signal from your iPad or another computer and communicates that signal over DisplayPort protocol. On the other hand, it gives you one more tiny dongle to carry around and potentially lose in the bowels of your backpack or camera bag.
Personally, I didn’t mind the dongle, and the extra tricks that it enables make Luna the most versatile option of the bunch. Not only does it allow you to turn an iPad into a second display with full touch and Apple Pencil support, it can also turn another Mac into a second display, or use your iPad as the main display for your Mac mini in what’s called “headless” mode.
The same features will be available on Windows once that variant of Luna is ready to ship.
I also found that the experience — whether wired in with an extra cable, or wireless over WiFi — was equivalent to Astropad Studio… which is to say, good. I still experienced some stuttering when performing heavy tasks over WiFi, but had zero problems on long photo editing sessions when I plugged in the iPad over USB. The downside here, of course, is that I was already sacrificing one USB-C port to the Luna Display dongle itself, so plugging in the iPad meant giving up another precious port.
For photographers, the main downside of Luna Display is that Luna was designed first and foremost as a way to turn an iPad into a second display. As such, pen and touch capabilities take a backseat. It doesn’t feature any of the shortcuts you’ll find in Astropad Studio, no Magic Gestures, multi-touch support is limited to pinch-to-zoom and swipe, and customizability is pretty much limited to display arrangement and resolution.
Astropad apparently knows that this might be an issue for some users, which is why you can actually use Astropad and Luna together if you’re fortunate (or loaded) enough to own both. Plug in Luna and turn on Astropad, and you now get Astropad’s intuitive and full-featured drawing UI on your iPad as a second screen, using the Luna dongle to essentially bypass Astropad’s “mirror mode only” limitation.
That’s great, but I can’t sit here and recommend that you purchase a $130 Luna Display and pay $80/year for Astropad Studio, even if that does provide the best photo editing experience on an iPad. It’s simply too much money. As it stands, I’d recommend Astropad over Luna, and both of them together over anything else, but I can’t tell you that it’s worth $210 plus $80 per year for as long as you both shall live.
Duet Display is the last entry in our roundup, and it comes in three flavors: Duet, Duet Air, and Duet Pro.
Duet and Duet Air are limited to using your iPad as a second display or remote desktop (Duet Air only), with no proper Apple Pencil support. As such, they’re not considered here. Our contender is Duet Pro, which will cost you $30 per year and includes all of the important drawing features we’re looking for like support for pen pressure and tilt, line smoothing, and multi-touch gestures.
Duet Pro is like Astropad Studio if Astropad Studio could turn your iPad into a secondary display. Like Astropad, it offers lots of useful gestures, lets you customize your pen pressure curve, and is optimized to work with photo editing and illustration applications. Unlike Astropad, it’s not limited to mirroring your computer’s screen. It’s also the only option that already offers full support for Windows and has for some time—no betas, no ‘pre-order,’ you’re good to go.
Of the four options tested here, Duet Pro was probably the least reliable for me. It threw the most glitches, stuttered the most over a wireless connection, and once froze my computer solid when I tried to adjust the resolution from System Preferences instead of the Duet desktop app. Don’t get me wrong, most of the time Duet Pro worked flawlessly, but I have to mention the few glitches I experienced because the other three options were all so stable.
Minor issues aside, Duet Pro matched Astropad Studio and Luna Display step for step in terms of the smoothness of its wired and wireless connection. I opted for wired most of the time for the sake of mitigating latency but could use it wirelessly in a pinch with no problem.
As far as customization and UI, it’s not quite as full-featured or user-friendly as Astropad Studio. You can still change the pressure curve, and there are some useful shortcuts and gestures like two-finger tap to undo and one finger hold to hover, but the app’s menu is sort of “hidden” and the UI takes some getting used to.
The one place where it beats Astropad outright is compatibility. Duet Pro is compatible with Macs running anything from MacOS 10.9 onward, and any iPad running iOS 10 or later will work; and, as I already mentioned, it’s already fully compatible with Windows as well.
Overall, Duet Pro is a good option if you’re a Windows user and/or can’t stomach the cost of Astropad Studio. At $30/year, it’s certainly a lot cheaper than AstroPad. But the features aren’t quite as polished and the UI isn’t on the same level, making it a harder sell if you have access to Sidecar or you’re willing to wait for Astropad to release the full version of Astropad Studio for Windows later this year.
And the winner is…
For the most full-featured experience with the best support for photo editing and illustration with the Apple Pencil, choose Astropad Studio. Duet Pro can’t match the sheer customizability of Astropad, and if you wind up getting a Luna Display down the road, you can use the two together for the ultimate photo editing experience on an iPad.
There’s simply no comparison between using Astropad Studio and using Apple’s Sidecar or even Duet Pro. Astropad’s commitment to creators is evident. It’s baked into the DNA of this product through and through and now that it’s coming to Windows, I have no good reason to tell you to choose another option.
I just wish they’d sell something similar as a one-time purchase instead of asking us to pay $80/year for the foreseeable future. That structure should encourage Astropad to keep improving the app year-in and year-out, but it also means that it’s only worth the cost for those photographers who are willing to integrate the app into their professional workflow.
For most people, Sidecar is good enough. It has the smoothest performance of the bunch when you’re connected wirelessly, can be used as a mirrored or secondary display, supports full pen pressure and tilt, and gives you the bare-bones shortcuts and multi-touch gestures you need for enthusiast-level photo editing on an iPad.
The customizability is lacking, compatibility is limited to new-ish computers and iPads, and it will never be available to Windows users. If that disqualifies you, consider spending the $30 on Astropad Standard or checking out Project Blue. But if you own compatible hardware and you don’t consider yourself a power user who plans to use the iPad for serious photo editing, stick to Sidecar. Your wallet will thank you.