No B.S. guide to monitors (for developers)
You'd think choosing a monitor would be easy: just get the most inches and pixels available for your budget - job done. Bigger means better, right? Not exacty.
This post is written for someone who uses macOS and spends most of the day looking at text. If you're into gaming, video/photo editing or something else, your mileage might vary.
- Look for PPI value close to 110 or 220
- Retina displays look awesome, but do not improve your productivity
- Prioritize quality stand and USB-C connectivity with power delivery
- Consider window management before choosing ultrawide or multiple monitor setup
- Screen size should come last
In Apple we trust
As with many things in life, you can solve this problem quicker by throwing money at it. If you do not care about the price and simply want the best, just go ahead and get LG UltraFine 4K or 5K monitor. Those models were designed in collaboration with Apple, so they are pretty much guaranteed to deliver a good experience on MacOS. I've been fortunate enough to have tried both and 5K is my main display in the office. Their design is a bit uninspired - and that's coming from someone who usually enjoys utilitarian design - and they have no ports apart from thunderbolt and usb-c. It all ceases to matter once you turn it on and glimpse at the screen. Those truly are the best of the best. Though if you're ready to spend that amount at money on a monitor (5K goes for 1400eur where I live), I'd consider throwing in a few hundred euros more and geting the whole iMac. You'd be getting a better looking device, wider port selection, decent speakers, oh and a powerful computer too. Just seems like better value.
The rest of us
For those of us who do not wish to spend that kind of money on a monitor, do not despair - there are still plenty of choices. You just need to understand what matters, what doesn't, and what trade-offs you're willing to make.
Pixel density is king
The single most important number that describes your day-to-day experience with a monitor is not the resolution or screen size, but the combination of the two - pixel density. You'll most often see it measured in PPI, meaning pixels per inch. All other things being equal, bigger PPI will mean a sharper image. However, more is not necessarily better, as operating systems are designed with a specific PPI values in mind. For macOS it happens to be somewhere around 110 PPI; Windows look best ar roughly 95 PPI. Go higher than that and UI elements can become too small to see without straining. "But in that case can't I just scale it out?" You can, but scaling is not a solved problem. If you care about image quality, you cannot zoom in by any arbitrary factor (see explainer about Retina). If you've ever tried to set your display to a non-native resolution only to have everything come out blurry, you already know this. It also depends heavily on individual apps - some are better at scaling than others. Unless you have a good reason for going against that, I'd stay near the expected PPI for each operating system.
What Retina actually means
Retina is simply Apple's trademark for using high pixel density displays to show 1 logical pixed using 4 physical ones. This results in a very sharp visuals, where you cannot see individual pixels from the usual viewing distances - ~60-70 cm. for desktops, 30-40 cm. for laptops, and even less for smartphones. Since it depends on the viewing distance, there cannot be some fixed PPI value. That's why iPhones have a PPI value of 300-400, and yet iMacs have ~220.
There's no magic involved - any device with sufficiently high PPI can be used as a Retina display. The important thing to understand is that Retina will look much sharper, but it will not improve your productivity. Logical resolution is 4 times smaller than physical resolution, so 4K (3840 x 2160) offers the same amount of screen space as fullHD (1920x1080), and 5K (5120 x 2880) compares to WQHD (2560 x 1440). You can choose a non-default scaling factor to have more or less screen space on the retina screen, but I'd caution against that. Your mac's GPU will have to work harder on each frame (expect your laptop fans to kick in more frequently) and there will be rounding errors in calculated pixel positions. This can cause jittery animations and blurry visuals, which kinda defeats the whole point of a retina display. Scaling UIs isn't a solved problem too, though MacOS apps are pretty good at it, since they've been doing it the longest.
Honestly, for looking at text, any panel type will do. However, unless you found a really good deal or are tight on money, I'd skip TN or VA panels and go straight to IPS. You'll get better color accuracy and viewing angles for not that much more money.
Other features and considerations
Compared to other devices, monitors progress at snail's pace. Any monitor you get can be reasonably expected to last a decade, and is almost guaranteed to outlast your current laptop and maybe even the next one. That's why it makes sense to future-proof you purchase and think about features that will matter in the long run.
Unless you plan to buy a separate monitor arm, prioritize a solid monitor stand. Personally, adjustment is not as important as stability - it's super annoying when typing makes monitor wobble. The old Apple Thunderbolt display had no adjustability apart from tilt, but it was the most stable monitor I've ever worked on.
Another thing to get in 2020 is USB-C with power delivery. If your current laptop does not support it, you next one definitely will, and you'll want to use it, so be prepared. Speakers, blue light filters, freesync, HDR, and other marketing mumbo jumbo can be ignored, unless you already know why you need it.
Multi-monitor setups and ultra wide
Don't have much to say - I've tried multi-monitor setup briefly and didn't like it. Too much time spent managing windows and looking for things. In my workflows I rarely need more than 2 or 3 windows open at once, and that can easily fit on a single monitor. Whatever camp you fall into, consider your workflows before upgrading to a completely new monitor setup, like ultra wide. Window management is not a trivial problem, so make sure you have a plan for making use of all the screen space. If you decide to go with multiple monitors after all, then include daisy-chaining into your list of requirements.
Putting it all together
Now that you understand all that, choosing a monitor is easy:
- Get an IPS WQHD (2560x1440) at 27 inches - coincidentaly the same exact resolution and size of the original Apple Thunderbolt display :)
- OR get a 5K at 27 inches - this will scale to logical WQHD resolution, but will look NICE. Unfortunately not many choices with 5K monitors yet, and all of them are pretty expensive
- OR get a 4K at 22-24 inches. Will scale down to a nice and sharp fullHD. You get much less real estate than with WQHD, but it should still be plenty adequate
- If you're completely broke, consider getting full hd monitor, but then don't go higher than 22', or else your PPI will come into double digits, and that's just depressing
New monitors with minor upgrades are coming out every year, so always check if there are new and improved versions.