For the Pixel 4's face unlock feature to work in the dark, Google had to add a front-facing IR camera. If you download a specific app, you can actually see a live feed from this camera. It's true night vision for your phone, and it's completely free.
So grab HedgeCam 2 from the Play Store. Open the app to the main screen and tap the camera switch icon twice to jump into the IR camera. You'll notice the colors shift to an inverted look — you can now see in the dark using your Pixel 4.
- Play Store Link: HedgeCam 2: Advanced Camera (free)
You can snap a photo or record a video using the IR camera. Though it's not a very high-resolution camera mode (640 x 480), it'll still make for some interesting shots you couldn't get with a regular RGB cam. You can even get your inner ghost hunter on while you're at it!