Removing Red-Eye with Your Nikon D3400
For portraits marred by red-eye, give the Nikon D3400’s Red-Eye Correction filter a whirl, as shown. If the camera detects red-eye, it applies the filter and displays the results on the screen.
Press the Zoom In button to magnify the display, as shown in the figure, so that you can closely inspect the repair. (Use the Multi Selector to scroll the display as needed while zoomed.) Press OK twice if you’re cool with the job the camera performed: The first press returns the display to normal magnification; the second makes the change official. To instead cancel the repair, press the Playback button.
Note that the filter can correct only red-eye; it can’t fix animal eyes that a flash has turned white, yellow, or green. If the camera can’t detect red-eye or you didn’t use flash to take the picture, the Red-Eye Correction menu option is dimmed and unavailable.