Glasses reflect light when taking pictures.

This is the angle between the flash and the glasses lens.

When the flash line deviates from the lens, it will not reflect light. The following methods can be used to avoid reflection: first, direct the flash lamp outside the glasses lens; The second is to shoot down, so that the flash line is outside the lower edge of the lens; The third is to shoot on the left or right, so that the flash line deviates from the glasses.

Maybe you are taller than your friend, holding a camera or squatting to take pictures of your friend, and your friend likes to take pictures of you head-up.