red eye

Definition: Bright red dot which may be seen in the eyes of subjects photographed with electronic flash: it is caused by light entering the eye and being reflected from the blood-rich retina to the taking lens. * The basic conditions for red eye are (a) dark ambient conditions, which cause the pupils to dilate (b) flash lighting which is of too short duration to cause pupils to close down (c) flash lighting which is very close to the optical axis (d) subjects looking in general direction of the taking lens.

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