Hidden cameras and disguised “paper-thin” cameras in accommodation facilities such as guesthouses and hotels are always a source of concern for many people. If such devices are present in a room, personal images and private information may be exposed, seriously affecting one’s personal life. Therefore, guests should be careful to check their rooms for any unusual devices. If relying only on the naked eye, detecting recording devices can be very difficult because they are often extremely small and hard to see.

Recently, a tip for finding hidden cameras in hotel or guesthouse rooms has been shared on social media and attracted a lot of attention. According to this method, iPhone users can use the Magnifier feature combined with the “Red on Black” color filter to check hotel rooms, guesthouses, or other locations for hidden cameras. Although this method cannot guarantee detection of all covert recording devices, it is still a useful approach and can be combined with other inspection steps to better protect the renter’s privacy.

Below are the specific steps for using the Magnifier feature on an iPhone to look for hidden cameras.

How to use the iPhone “Magnifier” feature to find hidden cameras

The Magnifier app helps highlight tiny light points in dark environments—these may be suspicious signs of hidden cameras and can then be examined more closely. The mechanism relies on color filters, specifically the “Red on Black” option. This mode makes small light sources stand out more clearly against a dark background.

The process is very simple. Open the Magnifier feature on your iPhone, tap the filter icon at the bottom, and select “Red on Black.” Next, turn off all the lights in the room and close the curtains tightly to ensure no external light enters. Once the room is completely dark, slowly scan the entire space with your phone, paying special attention to areas such as the TV, mirrors, power outlets, electrical devices in the bathroom and dressing area, tables, and similar spots.

If an active camera is present, unusual bright dots may appear on the iPhone screen. The next step is to carefully inspect the area where these bright spots appear.

The iPhone’s Magnifier feature can help detect signs of hidden recording cameras in guesthouse or hotel rooms.

Other ways to detect hidden cameras in hotel or guesthouse rooms

Using a flashlight or camera flash

If you do not have an iPhone, you can use a flashlight or phone flash to search for hidden cameras. This method is straightforward: close all doors, turn off the lights, and draw the curtains. Then use your phone’s flashlight to scan all corners of the room. Camera lenses may reflect the light back.

Devices mounted on the ceiling or walls facing the bed, power outlets, electronic equipment, wall decorations, bathrooms, and changing areas are common locations where hidden cameras may be installed.

Using your phone’s camera

You can also use your phone’s video recording mode to check for abnormalities in the room. Many mini cameras use infrared lights to support recording in low-light conditions. These infrared lights are invisible to the naked eye but can be detected by a smartphone camera.

Turn off all the lights, close the curtains, and open your phone’s camera. Then scan the room, especially suspicious areas. If you see unusual bright dots on the phone screen, this could be a sign of a hidden camera.