Red-Eye is caused by which phenomenon?

• A. Light reflecting back from the retina
• B. Lens flare
• C. Sensor bloom
• D. Chromatic aberration

Answer: (A)

Red-eye happens when light from a flash reflects off the retina at the back of the subject’s eye and travels back through the pupil to the camera. The pupil is dilated in low light, so a lot of light enters, hits the blood-rich retina, and comes back to your lens, giving that characteristic red glow from the blood vessels. This is different from lens flare, which is stray light scattering inside the camera lens; sensor bloom, which is saturation causing bright pixels to smear; and chromatic aberration, which is color fringing around edges due to how a lens bends different colors. To reduce red-eye, use red-eye reduction features, increase ambient lighting so pupils contract, or move/bounce the flash or use off-camera lighting.