Why Do Phones Flash On Camera?

Infrared Light Visible To Cameras

• iphones flash infrared light and night vision cameras can detect infrared light. same thing with traditional tv remotes.
• the iphone is emitting light, and the camera can detect it. it would be true of most tv remotes (when you push the button too).
• video sensors can detect light outside the range of human vision.
• infrared light can't be seen by the human eye.
• the flashing that i speak of is infrared, and it flashes about 15 times per second. you cannot see it without an ir viewing device. i accidentally spotted it with my night vision unit.

Face ID Infrared Dots

• more specifically, iphones with a feature called "face id" have an infrared (ir) light on front of the phone that projects a pattern of dots when the phone is locked and then moved.
• the camera on the front of the phone looks at the pattern and uses that to measure features of the face to determine if the face looking at the phone is the phone's owner.
• i think it’s also using ir for range finding. iirc it uses that info for focusing the camera and making depth of field effects.
• iirc the front facing camera on the iphone doesn't show the ir light.

Dot Projector And Infrared Camera

Face ID phones

i presume it is an iphone with faceid, the iphone's with face id (iphone 11, iphone x, etc) use infrared dots (from a dot projector) to put the dots on your face (when you try and use faceid), then an infrared camera in the phone looks at these dots on your face to determine the depth

Facial features and depth

the phone's with faceid use an infrared system to determine your facial features and the depth of your nose, your eyes, etc, and what you are seeing is the infrared dot projector projecting infrared light onto someone's face

It fires no matter if it sees a face or not

or well, trying to, it fires no matter if it sees a face or not

Security Cameras And Doorbell Cameras

• doorbell cameras, however, are designed so that they'll work well at night, so they tend to not have ir filters because they want to gather as much light as possible so that they can get a relatively clear picture.
• some even incorporate a little ir light to provide illumination (again, you can't see infrared, but the camera can see it).
• so, when something in the picture is emitting infrared light, it shows up as flashes.
• these flashes were not visible to their naked eye. we presume they are infrared flashes but what the heck is that?
• my iphone 12 pro max is flashing a light multiple and various times. a flashing light that i do not see but is visible on security camera video footage.
• does anyone know why my iphone 12 pro max is, because of an unknown action, flashing light that is invisible to the eyes but visible when viewed by security camera video footage.

Filters And Camera Detection

• things like camcorders often have filters that block (greatly reduce) infrared and ultraviolet light, so it's not as noticeable.
• still, if you point a tv remote directly at a camcorder, you are likely to see the light flash because it's actually quite bright (you just can't see it).
• you can also see this effect if you point the remote at the camera, or even (since the iphone's front facing camera doesn't have an ir filter) point something like a remote into the front facing camera of an iphone and you'll see the infrared light
• i mean you open your iphone's camera, flip it so its the front facing camera, and the phone shows it as either purple, or red (most of the time its purple)

Testing With A TV Remote

• if you ever need to test if a tv remote is working look at it with your phone camera .
• it can sometimes be difficult to know if batteries are dead, remote not working or tv not receiving.
• the iphone is emitting light, and the camera can detect it.
• it would be true of most tv remotes (when you push the button too).

Lock Screen And Notification Flash

• did you turn on led light notifications (led flash alerts)?
• you may have accidentally turned this on in the settings of your phone (or you turned it on but forgot).
• this will make the camera flash will light up when you get a notification.
• so check to make sure you didn't turn on this feature.
• if you have an iphone, go to settings > accessibility > audio/visual > led flash for alerts, then make sure it's turned off
• if you have an android phone, go to settings > accessibility > hearing > flash alerts, then make sure it's turned off
• it's also possible you accidentally triggered the camera shortcut.
• you can access the camera from the lockscreen on iphone and android, it's basically a quick shortcut.

Proximity Sensor And Automatic Brightness

• i understand that it's used as a proximity sensorbut still....
• it's used to turn off the display when the phone is put up to one's head or maybe even keep the display off when in the pocket.
• there is no reason a proximity sensor should flash when the power button is pushed to turn off the display.
• being that the phone does not have that functionality it makes sense to disable the ir flash for the sake of power consumption.
• does it help if you turn off automatic brightness from system settings?
• i always keep the auto brightness off

Observed Infrared Flashing

• recently had a creepy experience. installed our petcube pet camera in our new house snd the first night, it caught motion.
• it was my daughter and her boyfriend, watching tvs on the couch, not looking at their phones, and they were both flashing every few seconds as if it was taking pictures.
• these flashes were not visible to their naked eye.
• my partner was viewing our security cameras' footage because the cameras had notified us of motion in specific areas.
• he observed that every so often, my iphone 12 pro max was flashing white "camera" lights in several bits of various camera video footage.
• when he showed me what was on the video cams' footage, i was shocked.
• there were flashes of light coming from my iphone 12 pro max and it appears as though i am doing some action (logging in, texting, something) to cause the flashing to occur.
• i never saw the flashes happen and i certainly did not take the photos he saw on video footage.