Nikon D5300 Reference Manual - Page 205

a3: Built-in AF-assist Illuminator G button ➜ A Custom Settings menu Choose whether the built-in AF-assist illuminator lights to assist AF-assist illuminator the focus operation when lighting is poor. Option On Off Description The AF-assist illuminator lights when lighting is poor (for more information, see page 252). The AF-assist illuminator does not light to assist the focus operation. The camera may not be able to focus using autofocus when lighting is poor. a4: Rangefinder G button ➜ A Custom Settings menu Choose On to use the exposure indicator to determine whether the camera is correctly focused in manual focus mode (0 57; note that this function is not available in shooting mode M, when the exposure indicator instead shows whether the subject is correctly exposed). Indicator Description Subject in focus. Focus point is slightly in front of subject. Focus point is well in front of subject. Indicator Description Focus point is slightly behind subject. Focus point is well behind subject. Camera can not determine correct focus. A Using the Electronic Rangefinder The electronic rangefinder requires a lens with a maximum aperture of f/5.6 or faster. The desired results may not be achieved in situations in which the camera would be unable to focus using autofocus (0 52). The electronic rangefinder is not available during live view. A Custom Settings: Fine-Tuning Camera Settings 185