To be clear, Night Sight hasn’t actually officially rolled out yet. Google announced the feature during the Made By Google event but said that it would roll out for the Google Pixel 3 and other Pixel devices sometime next month. However, the latest version of the Google Camera app which rolled out to users earlier today has a fully functional Night Sight built-in. XDA Senior Member cstark27 decompiled the app, changed a single boolean value from false to true, and recompiled the app. With his modded Google Camera app, we were able to try out the new Night Sight feature on the Google Pixel 3 XL, Google Pixel 3, Google Pixel 2 XL, and original Google Pixel.
Home Photography Google Camera with Night Sight Mode enabled