Why does my S9+ video dim and lighten off and on during the video for no reason

[Android Central Question]

I video'd a outdoor sunny interview and when we play them back the camera is going slightly dark and lighter over and over. How do I stop that?

 

[lucianus_luciferus]

Have you tried playing the file on your computer? Or another phone?

 

[theGiantMidget 2000]

I'm assuming you have the screen brightness set to automatic so when you hold your phone in landscape mode you are likely blocking the light sensor with your hand so the phone thinks it's in a dark room and drops the screen brightness.
you can test this easily by holding your thumb over the top of your screen for several seconds. If the brightness goes down there's your answer.

to turn that off when watching a video or whatever open the notification bar as you normally would to change the brightness and hit the dropdown arrow at the right of the brightness bar. Select auto brightness.

 

[daddycools]

No it shows up on the finished video. Nothing to do with the homescreen

 

[daddycools]

Yes it does this when I review the video on my computer. It only does it on my phone not my wife's duplicate phone