When you set a Nikon camera to shoot in automatic mode, the camera automatically adjusts its settings to compensate for lighting conditions at the moment you press the button to take the picture. Although this typically involves the flash in low light situations, it isn't always necessary – and therefore, doesn't always go off – while using automatic mode.
No matter which model you use, Nikon cameras give you the option to shoot subjects in low light using flash. Several factors may be responsible if you experience a flash failure when using a Nikon camera.
Sometimes, you may want to use the flash even if the lighting suggests you don't need it; the flash is sometimes valuable in medium- or high-light situations, particularly when shooting peoples' faces. Set the camera into manual or "M" mode. On digital and analog SLR Nikon cameras, press the "Flash" button on the left side of the camera body to turn on the option. On a point and shoot camera, change the "Auto" flash option to "On."
All Nikon cameras come with a built-in flash, which sits inside the camera body of point-and-shoot models and on top of the camera body for SLR cameras. If you have properly adjusted your settings and your flash still doesn't work, your built-in flash is defective. Take the camera to a Nikon-authorized repair specialist. Alternatively, if you have an SLR camera and you feel comfortable removing the flash yourself, you can slide the flash off and replace it with a new one.
Nikon SLR cameras accommodate external flashes, which give you greater flexibility in terms of where the flash goes off. If your external flash isn't working, disconnect it from the computer and replace it with the built-in flash. If the built-in flash works fine, a problem exists with the external flash and it needs to be repaired or replaced.