How to use an iMac as an external monitor

If you own an iMac and want to use it as an external monitor for your laptop or desktop, you're in the right place. In this article, we'll show you how.

The iMac is an all-in-one computer with a high-quality display that can be used as an external monitor for other devices. This feature is particularly useful if you need more screen space or if you want to work on a different device without having to purchase a new monitor.

Continue reading to learn how to use your iMac as an external monitor.

Checking Compatibility

Before using your iMac as an external monitor, it's important to check its compatibility with the device you want to connect. This mainly depends on the type of ports and connections available on both devices.

Your iMac's Ports

To use your iMac as an external monitor, you must have an iMac with a Thunderbolt or Mini DisplayPort port. You can check if your iMac has these ports by checking the model specifications on Apple's website.

Ports of the Device to Connect

In addition, the device you want to connect to your iMac must have a port compatible with that of your iMac. For example, if your iMac has a Thunderbolt port, the device you want to connect must have a Thunderbolt or Mini DisplayPort port.

Otherwise, you may need to purchase an adapter to convert the device's port into one compatible with the iMac.

Screen Resolution

Finally, it's important to consider the screen resolution of the iMac and make sure it's compatible with that of the device to connect. For example, if the device has a maximum resolution of 1080p, but your iMac has a resolution higher than 1080p, you may not be able to use the iMac as an external monitor at maximum resolution.

Practical Example

Suppose we want to use a 2011 iMac as an external monitor for a 2015 MacBook Pro. Our iMac has a Mini DisplayPort port, while the MacBook Pro has a Thunderbolt port. To connect the two devices, we need to purchase a Mini DisplayPort/Thunderbolt adapter.

In addition, we need to consider the screen resolution of the iMac. Our iMac has a resolution of 1920x1080, while the MacBook Pro has a resolution of 2560x1600. So when we use the iMac as an external monitor for the MacBook Pro, we won't be able to use the MacBook Pro's maximum resolution.

• Check compatibility of ports between devices
• Consider iMac screen resolution and make sure it's compatible with that of the device to connect
• You may need to purchase an adapter to convert the device's port into one compatible with the iMac

Cable and Port Setup

To use your iMac as an external monitor, you will need a compatible cable and an available port on your iMac. Most iMacs produced after 2011 support Target Display mode, which allows them to be used as external displays.

Compatible cables

The compatible cables for connecting your iMac to another computer or device are:

• Thunderbolt cable: used to connect two Macs via the Thunderbolt port.
• Mini DisplayPort cable: used to connect two Macs via the Mini DisplayPort.
• HDMI cable: used to connect your iMac to an external device with an HDMI port.

Make sure you have the right cable based on the available ports on your iMac and the external device you want to connect.

Port configuration

Once you have the appropriate cable, follow these steps to configure your iMac's port:

1. Connect one end of the cable to the corresponding port on your iMac.
2. Connect the other end of the cable to the corresponding port on the external device.
3. Turn on both devices.
4. Press the "Cmd + F2" key combination on your iMac keyboard to activate Target Display mode.

If you have an iMac with a Thunderbolt 3 (USB-C) port, you may need an adapter to connect your external device. Make sure to purchase an adapter that is compatible with both ports.

Troubleshooting

If you encounter issues while configuring the cable and ports, try these tips:

• Make sure the cable is securely connected to the corresponding ports.
• Check that both devices are turned on.
• Check the display settings on your iMac and external device to ensure they are compatible.
• Restart both devices and try again.

Display settings

After connecting your iMac as an external monitor, it's important to properly configure the display settings for the best possible experience.

Screen resolution

The screen resolution determines the sharpness of the image on the screen. To set the resolution, go to System Preferences > Displays and select your desired resolution.

It's important to choose a resolution that is compatible with both devices. If the iMac has a higher resolution than the external device, you may notice a decrease in image quality. In this case, try reducing the iMac's resolution.

Screen orientation

The screen orientation can be set to horizontal or vertical. This option is useful if using the external monitor for activities such as programming or reading long documents.

To set the screen orientation, go to System Preferences > Displays and select your desired option under "Orientation".

Shared Screen Mode

If you want to use your iMac as an external monitor while still using the computer, you can use Shared Screen mode. In this mode, your iMac acts as an external monitor while the computer continues to function normally.

To activate Shared Screen mode, go to System Preferences > Displays and select "Use as a separate display".

Mirroring Mode

Mirroring mode allows you to display the same content on both devices. This option is useful if you want to use the external monitor for presentations or to share videos with others.

To activate Mirroring mode, go to System Preferences > Displays and select "Mirror Displays".

• Remember to choose the best screen resolution compatible with both devices.
• Choose the screen orientation according to your needs.
• Use Shared Screen mode if you want to use your iMac as an external monitor while still using the computer.
• Use Mirroring mode if you want to display the same content on both devices.

Troubleshooting

If you encounter problems using your iMac as an external monitor, here are some solutions that may help:

No signal on the screen

• Make sure the connection cable is properly connected to both devices.
• Check that the iMac is set up to work as an external display. Go to System Preferences > Displays and select "Allow other computers to control this display".
• Try restarting both devices and retry the connection.

Screen unable to display desired resolution

If the iMac screen is unable to display the desired resolution, try these options:

• Change the screen resolution on the other device connected to the iMac. You may need to reduce the resolution to get a proper display.
• Update the operating system of both the iMac and the connected device to ensure you have the latest versions of drivers and software.

Flashing or visual artifacts on the screen

If the iMac screen has flashing or visual artifacts, try these suggestions:

• Check that the connection cable is securely connected to both devices.
• Try using a different cable for the connection.
• Make sure that both the iMac and connected device are set to the same screen refresh rate. Go to System Preferences > Displays and select the same refresh rate for both devices.

By following these guidelines, you should be able to solve most of the problems you may encounter when using your iMac as an external monitor. Otherwise, contact manufacturer technical support for further assistance.

Conclusion

Using the iMac as an external monitor is a useful function for those who work with multiple devices simultaneously or want to have a larger screen. With these simple steps, you can easily set up your iMac as an external display and enjoy a better visual experience. Always remember to follow the correct disconnection and shutdown procedures to avoid any damage to your devices. Happy working!