If you've ever tried to take a photo of something that’s on a screen, perhaps to share with friends, you'll have found the pictures look really weird. There’s a crazy pattern that overlays the screen and looks nothing like the image you can see with your eyes. It looks like it has world’s worst Instagram filter.
As more things happen digitally, there’s a growing need to be able to capture what’s happening on a screen as a picture. If you want to share a funny Facebook post to Instagram, or a Tweet with a WhatsApp group, sending an image is often the simplest way to do it.
It’s also really useful, when you’re looking for help online, to be able to show a picture of any errors shown. Obviously, taking screenshots is an important skill for all Envato Tuts+ writers.
In this tutorial, I'll show you why taking a photo of a screen doesn’t work, and how you should capture pictures of what’s on the screen of a Mac or iOS device.
Moiré, More Problems
Digital cameras don’t work anything like the human eye; screens are completely different to pieces of paper. Although this might seem obvious in theory, it’s at the root of why cameras and screens don’t play nicely together.
When you look at something, the brain is doing a huge amount of processing. It'll make up information to fill in any gaps.
A Hollywood film is just a stream of 24 still images per second played one after the other, but our brain interprets it as a scene that’s in constant movement. No matter how hard you try, you’ll never be able to see it as individual images.
Both screens and digital camera sensors are made up of a pixel grid. My MacBook’s screen has 5,184,000 pixels arranged into 1,800 rows and 2,880 columns. My camera, on the other hand, has 22,118,400 pixels in a 5,760 by 3840 grid.
When you look at the screen or take a picture with the camera, it might look like you’re seeing an image with curves and circles, but it’s actually just tiny squares arranged to look that way.
The strange pattern you see in digital images of screens is what happens when two grids interact. Unless the grids line up perfectly, you get some weird optical effects called moiré.
When you take a picture of a screen, the camera’s grid won’t be able to accurately represent the screen’s grid unless they’re aligned exactly. The camera has to make decisions about how bright and what colour each pixel is, and the algorithms it uses to do that start to fall apart when they’re applied to grids that are prone to moiré patters.
The camera is actually making these judgements with every image you take, it’s just that the effects aren’t as obvious as they are with screens.
How to Take Screenshots on a Mac
A screenshot is an image of a screen’s contents. It’s taken by the device and saved as a file. On a Mac, it’s simple to take a screenshot. All the screenshots you take are saved to your Desktop.
Take a Full Screenshot
To take a screenshot of the Mac’s full screen, press Command-Shift-3. A PNG file with the same resolution as your screen will displayed on the desktop.
Take a Screenshot of a Section of The Screen
If you don’t want to take a full screenshot, press Command-Shift-4. The cursor will turn into a crosshair that you can use to Click-and-Drag an outline around the area you wish to capture.
Take a Screenshot of a Single Window
To take a screenshot of a single application window or menu, press Command-Shift-4 and then the spacebar. Click on the window you wish to capture and it’ll be saved to the desktop.
Take a Screenshot With the Mouse Cursor
Normally, when you take a screenshot you’re interested in capturing the content on the screen, not the Mac’s UI. This means that macOS doesn’t save the cursor in the image files. If you want to take a screenshot that includes the cursor, you’ll need to use a different method.
Open Preview and go to File > Take Screenshot > From Entire Screen. A timer will start so position the cursor where you want it and wait until it runs out.
Rather than being saved to the Desktop, the screenshot will open up in a new Preview window. Save it to whatever location you wish.
Change Where the Screenshots are Saved
To change where screenshots are saved by default, open the Terminal and paste in the following command and press Return:
defaults write com.apple.screencapture location ~/Documents/
killall SystemUIServer and press Return again.
Now, all the screenshots you capture will be saved to the Documents folder. You can change the folder path to wherever you want.
How to Take Screenshots on an iOS Device
Taking screenshots on an iOS device is even easier. Press the Home and Lock buttons at the same time and you’ll hear a camera shutter sound.
Any screenshots you take on iOS devices are saved to the Camera Roll. If you open the Albums tab in the Photos app, you also find them in a dedicated Screenshots album.
Other Screenshot Tutorials
- ProductivityHow to Become an OS X Screenshot WizardJohnny Winter
- Tips & ShortcutsScreen Capturing and Screen Recording Like a BossAlex Spencer
- Apple TVHow to Take Screenshots on a 2015 Apple TV 4Johnny Winter
- MediaHow to Take and Edit Screenshots For TutorialsEd Lopez
- App TrainingUsing Skitch to Snap Perfect ScreenshotsAndrew Childress
If you want to record the contents of your screen, a screenshot is the best way to do it. Using a camera to take a photo just won’t work because of the moiré pattern effect. In this tutorial, I’ve looked at how to do it on a Mac and iOS device.