Most of these slave flash units are triggered when they see a bright light, or when the on-camera flash goes off. Point and shoot models usually have a ‘pre-flash’ that cause a slave flash to ...

If someone flashes a bright light in your eyes ... reflects off your eyes and goes back into the exposed film or the camera's sensor. The red emerges as a reflection of the blood vessels and ...

Improvised lighting solutions yielded mixed results, and he soon realized he needed a true camera flash. However, all the options he found online were large and bulky; larger than the camera ...

Rather, it occurs when someone is exposed to bright light, says Dr. Benjamin S. Bleier, a sinus specialist at Mass Eye and Ear. Sunlight is the most common culprit, but even a camera flash can set ...