If you own the Samsung Galaxy S5 and are searching within the camera's settings app after a night mode, then you will not find it. The night mode, which is known from the S4, is to help the user to make sharper pictures in dark places or in low light situations. This function was quite useful to make even in low light images with the smartphone.
Night mode is fortunately not completely gone on the Samsung Galaxy S5, but only the name of this option has changed. The night mode on the Samsung Galaxy S5 is now called "Picture stabilization". If this option is active on the Samsung Galaxy S5 , the camera of the smartphone automatically detects low light conditions and optimizes the picture settings.
To activate the "picture stabilization" night mode on the Samsung Galaxy S5, open the camera app and then tap on the icon that looks like a gear. Picture stabilization can now be found in one of the tiles within the settings menu.
You know now that you can find on the Samsung Galaxy S5 a night mode for taking pictures at night, and how activate it.