The Complete Guide to Buying an External Display for Your Mac

Apple sells more portable Macs than desktops - but that’s a lot of Macs with a display of 15” or less. You can use an external display on any portable Mac and iMac but so many different display types, connectors, sizes, how do you know what type of display to go for? In this guide we’ll explore how you can find your perfect second (or third) display.

Why An Additional Display?

If you often find yourself ⌘-Tabbing between apps on your Mac or you’ve ever attempted to use an app such as Xcode on an 11” Macbook Air then you may benefit from some additional screen real estate. Having a second display allows you to make use of many more pixels. To best explain how a second display can aid your workflow, I’ll briefly describe my set up.

My Mac is an 11” MacBook Air. I love it to bits and it’s honestly the best Mac I’ve ever owned. However, I’m a freelance web designer and working on an 11” MacBook Air is not only difficult, it’s counter-productive.

I also have a 24” display attached to the MacBook Air. It supports a maximum resolution of 1920 x 1080 which means I can happily work all day at my desk with my MacBook Air effectively becoming a desktop Mac with a 24” display. In addition, I use a stand for my MacBook Air so I also have the benefit of an 11” display that I have Mail or Safari open in at all times.

An external display can give you more room to work

In addition to being able to have more open on your screen at once, apps such as Aperture or iMovie have some great features that take advantage of a second display. For example, iMovie on a single display tries to show the movie timeline, preview and Events viewer all on the same window, with the preview squeezed into the top-right corner. Using a second display, you can have the preview on the smaller display and have the iMovie project on the larger display.

Having a second display allows you to make use of a lot more pixels…

I’ve seen users base their decision for purchasing an iMac simply because the display was bigger without realising portable Macs have the ability to use an external display.

Are Two Displays Better Than One?

For some users, the thought of two displays side by side can be a little overwhelming - or unnecessary. What if you want the benefit of an external display but don’t want to have two displays? Apple’s portable Macs include a function called Closed Clamshell Mode.

Introduced way, way back with the PowerBook G4, Closed Clamshell Mode lets you use your portable Mac whilst it’s closed. You will need an external (wired or wireless) keyboard and mouse though (since your Mac will be closed).

You can also use your external display whilst your Mac is closed

With the lid on your portable Mac closed, simply connect your display, power supply, keyboard and mouse. Your portable Mac will wake up and you can now use it just like a desktop! What’s more, there are plenty of stands from companies such as Henge that specifically take advantage of this so you can have your Mac taking up almost no room on your desk so it’s ready to use as soon as you’re wanting to start work.

Companies such as Henge offer unique docking solutions for your Mac

Connector Type

Over the years there’s been a number of different connector types for displays and all of them are currently in use today on displays.

VGA
DVI
Dual-Link DVI
HDMI
Mini DisplayPort
Thunderbolt

VGA

Compatible with: VGA only displays

VGA is a connector that is still in use on many computers today. It dates back to the days when CRT displays (some of you may be too young to remember these, you lucky people) were the norm and it’s included on modern LCD displays simply to allow them to work with VGA-equipped computers.

It’s described as an “analog” connection - it transmits channels of red, green and blue (RGB) as well as horizontal and vertical sync and some other display settings. However, your Mac is digital which means your Mac has to convert a digital image to analog, transmit it over the cable where the monitor converts it back to digital and then displays it. Because it’s an analog connection, it’s susceptible to interference that would distort the image - this distortion can appear as static or a shaky image.

The rest of the connector types are digital which means there’s no interference - either the image will appear or it won’t.

DVI

Compatible (via adapters) with: VGA, HDMI displays

DVI was created specifically to work with digital displays such as LCDs. Unlike VGA, it’s a digital connection which means there’s no conversion and the image is transmitted as data.

Some Macs shipped with Mini-DVI, it’s the same as DVI but used a smaller connector that required an adapter to be used regardless.

Dual-Link DVI

Compatible (via adapters) with: VGA, DVI, HDMI displays

DVI operates over a single channel - think of it as a single cable. Dual-Link DVI is the same type of connector (with some slight changes to the pins) and operates over two channels - it’s like there’s two cables running inside. This means it can support resolutions well beyond what DVI or VGA can support, such as 2560 x 1600 found on the old Apple 30” Cinema Display. Compared to an 11” MacBook Air which is 1366 x 768, that’s a huge difference!

HDMI

Compatible (via adapters) with: VGA, DVI displays

HDMI is an evolution of DVI and not only provides support for a digital image but also supports audio as well. You’re likely to have something such as a DVR or games console that is connected by HDMI.

Mini DisplayPort

Compatible (via adapters) with: VGA, DVI, Dual-Link DVI, HDMI displays

Mini DisplayPort is Apple’s implementation of DisplayPort - designed to replace VGA and DVI. Despite the fact it’s been around since 2009, it hasn’t been widely adopted.

Thunderbolt

Compatible (via adapters) with: VGA, DVI, Dual-Link DVI, HDMI, Mini DisplayPort displays

Connector-wise, it’s the exact same connector as Mini DisplayPort. However, Thunderbolt is a whole new generation if connectivity. It’s still based upon the DisplayPort standard but Thunderbolt allows displays to have even more features such as Apple’s Thunderbolt Display which offers USB, Ethernet and even daisy-chaining. This means that whilst Thunderbolt is the same connector type and standard as Mini DisplayPort, a Thunderbolt display won’t work with a Mini DisplayPort Mac.

Although Apple is (currently) the only manufacturer of a Thunderbolt display, it’s important to mention that it has an ace up it’s sleeve. Thunderbolt displays can be daisy-chained. Even on my 2012 11” MacBook Air, I could use two Apple Thunderbolt displays simultaneously in addition to my MacBook Air’s own display. That’s three displays in total! What’s more, with a Retina MacBook Pro, you can run two Thunderbolt displays and a third display via HDMI which totals a staggering 4 displays from one Mac!

Thunderbolt allows for some pretty amazing display setups!

Tip: It’s always best to use the correct display that matches your connector type. Whilst there is a plethora of adapters out there that will let you connect different display types to your Mac, you can avoid headaches by matching the best display accordingly.

Video Adapters

You will have noticed that for each connector type, I’ve included adapter options. For example, if you have an external display that only has HDMI, you will be able to use it with a Mac that has either a DVI, Mini DisplayPort, HDMI or Thunderbolt through the use of an adapter. Most display connector types are backwards compatible, so a Thunderbolt enabled Mac can connect to a DVI display. However, a Mac with a DVI port won’t work with a Thunderbolt display.

Currently, the Apple Store online stocks the following adapters:

For Thunderbolt-equipped Macs, you simply use the Mini DisplayPort.

What to Look For in a Second Display

There’s a number of factors you must consider when looking for an external display which we’ll look at in this section.

Screen Resolution & Aspect Ratio

The larger the native screen resolution the higher the number of different resolutions you can use — The larger the native screen resolution, the higher the number of different resolutions you can use.

Ideally, the higher the resolution a display can use, the better. If you work with HD video then you’d want to make sure you find a display that can output 1920 x 1080 (1080p). Some displays might only offer 1680 x 1050 which would mean your video would not display at it’s native resolution. Most displays are usually 1080p or above which should be the minimum you’re looking for.

Any Thunderbolt-equipped Mac should be able to support resolutions up to 2560 x 1600 which would mean that my humble 11” MacBook Air would be compatible with the 30” Cinema Display with a suitable adapter.

For Macs that include DVI or Mini DisplayPort, it’s recommended to check the Apple Tech Specs page to find out what resolution your Mac can support since this can vary from model to model.

Aspect Ratio refers to the proportion of width the to the height of the display. Most displays are 16:9 or 16:10 which allows a wider display and has been in use by Apple on it’s portable range for a number of years. If you remember the Apple PowerBook 12”, that had an aspect ratio of 4:3 which is very square.

Tip: LCD displays work best at their native resolution - in other words it’s highest setting. Anything less and the display won’t look anywhere near as good.

Screen Size

This is an important factor that’s based primarily on your workspace. You don’t want a huge 30” display if you’re on a small desk. Likewise, a 19” display would be too small on most workspaces.

On the flip-side, a 22” display that outputs 1080p will appear sharper than a 24” display of the same resolution since the pixels would be larger so bigger isn’t necessarily better.

Tip: Screen size is measured diagonally on a display, so a 24” display will be 24” from corner to corner.

LCD, LED, IPS?

When choosing the type of display to use you’ll no doubt see that a number of different models describe themselves as an LED or IPS display. However, this can be a little confusing since all LED and IPS displays are still LCD.

Before the advent of LED backlights in computer displays, there were a number of lighting tubes (very similar to fluorescent lighting and called Cold Cathode Fluorescent Lamps - CCFL for short) that ran across the width of the display. Whilst they were very bright, the backlight could not be truly uniform (since the tubes would have a bit of a gap between them) which meant some areas could look a little darker. Worse still, CCFLs take time to warm up so the screen wouldn’t be at full brightness for about 20 minutes.

LED backlighting works differently and provides a truly uniform backlight on the display, meaning no warmup time and a consistent backlight that avoids dark patches.

IPS (In-Plane Switching) is relatively new and is best known for it’s use in the iPhone and iPad. Unlike traditional LCD displays that have a small viewing angle before the colors appear to change and distort (you’ll notice this if you’re looking at a display almost side-on), IPS allows consistent viewing and colours from all angles. The benefit is that colours are consistent and more accurate.

Response Time

This is the time it takes for a pixel to change from one color to another. It’s usually measured in milliseconds (ms) and a display with a slow response time can suffer from an effect known as ghosting (or motion blur). For gamers, a display with a very quick response time is one of the most important factors to consider.

Viewing Angle

Unless you’re looking at an IPS display then viewing angle can be very important. The wider the angle, the better the image will be when looking at in from an angle.

Tip: In addition to checking the angle from left to right, check the display’s viewable angle from top to bottom.

Brightness

This is simply how much light the display produces. Displays are commonly found hovering around 250cd/m2. If you’re editing video or are using it to watch movies or play games, look around to see if a higher brightness rating is available.

Contrast Ratio

Contrast Ratio is defined on Wikipedia as the ratio of the luminance of the brightest color (white) to that of the darkest color (black). That would mean the higher the contrast ratio, the better… right?

Unfortunately, there’s no standard for Contrast Ratio. This means manufacturers often use their own “interpretations” of what the contrast ratio is. Some display manufacturers quote ratios of 1,000,000:1 yet compared to another manufacturer that quotes 50,000:1 there might be no visible difference. It’s important to always check product reviews on places like Amazon as well as check the display whenever possible. Buy a display from a reputable retailer that offers a good returns policy so that if the display isn’t right for you, you can return it.

Connectivity

Some displays offer built in speakers USB even a webcam — Some displays include additional functionality such as USB hubs and speakers. Whilst this is great to have, it shouldn’t be the basis of your purchase choice as often the speakers are average and a USB hub can be purchased very cheaply.

Versatility

Some manufacturers such as Dell include mounts that rotate so you can even have your external display in Portrait

Many displays feature a built-in stand as well as the ability to wall-mount it or mount it onto a custom display stand. Ideally, ensure a display has a tilt and swivel stand so that you can easily adjust it to achieve the best possible viewing angle. Additionally, some manufacturers such as Dell include mounts that rotate so you can even have your external display in Portrait.

Budget

At the end of the day, all the features we’ve talked about are dictated by budget. We’d all love to own one (or two) of Apple’s Thunderbolt Displays but unfortunately it’s priced out of reach of many users. However, don’t be disheartened as there are many displays out there that not only match the quality of Apple’s offering, they exceed it. Companies such as Acer, AOC, Dell, LG and Samsung manufacture some amazing displays.

Tip: Just like the companies I’ve mentioned, Apple don’t manufacture the LCD panel themselves. This is usually done by specialised manufacturers, such as LG, so often you will find that other manufacturers may even use the same display panel in their own offerings.

Wrapping Up

In this guide we’ve discussed how an external display can extend (or replace) your existing smaller screen. Whilst there’s a lot of information when looking at external displays, it’s always worth focusing on what’s important to you and starting from there. Don’t be afraid to check reviews and recommendations, head to electronic stores and try them out before using them.

Do you use an external display with your Mac? Let us know what you use in the comments.