Nikon D3400 Reference Manual - English - Page 220

Auto Distortion Control G button ➜ C shooting menu Select On to reduce barrel distortion when shooting with wideangle lenses and to reduce pin-cushion distortion when shooting with long lenses (note that the edges of the area visible in the viewfinder may be cropped out of the final photograph, and that the time needed to process photographs before recording begins may increase). This option does not apply to movies and is available only with type E and G lenses (fisheye, and certain other lenses excluded); results are not guaranteed with other lenses. A Retouch: Distortion Control For information on creating copies of existing photographs with reduced barrel and pin-cushion distortion, see page 237. Built-in AF-assist Illuminator G button ➜ C shooting menu Choose whether the built-in AF-assist illuminator lights to assist the focus operation when lighting is poor. AF-assist illuminator Option On Off Description The AF-assist illuminator lights when lighting is poor (for more information, see page 284). 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. 196 C The Shooting Menu: Shooting Options