A red box appears on the display of Nikon d5200.

The small red box on the screen is the focus box when focusing with the screen. You can focus in different positions after moving up and down. Focusing on the screen is different from focusing on the eyepiece. There will be no red frame in the eyepiece. Face recognition should be enabled when you meet a portrait, which is not a big problem and cannot be removed, because you can't take pictures without it. Don't take these as obstacles to your shooting. On the contrary, these things can help you better understand and use the camera. . . exceed