This is my first question on this site so forgive me for the awkward wording of the question. Basically, my question is why does light from, say, a sparkler, seem to remain where it just came from to you EYE? I attached a sample photograph and i understand that cameras work differently in that they're designed to "retain" light so to speak.
But why does the human eye have a similar, albeit less dramatic effect?
Best Answer
The human eye is actually quite similar to a camera. It also requires a finite exposure time to build up sufficient photon signal. If the source is moving over that time (typically about 0.1 sec for human eye), it will be blurred out over the exposure.