Answer:
The shutter speed is the measure of time the film is presented to light.
Explanations:
Screen speed is regularly discussed in divisions of a second (ex. 1/100) and once in a while entire seconds. In your camera's viewfinder, a shade speed of 1/4 is shown similarly as 4. A screen speed of 4 seconds is shown as 4 " (with a twofold statement a short time later to demonstrate entire seconds). Shade speed is the measure of time that the camera is allowing light from the focal point to hit the film or advanced sensor. A quick shade speed is useful for "solidifying" the activity of a subject in movement. A moderate screen speed is useful for intentionally obscuring the movement of a subject (note with a moderate shade speed it is for the most part wanted to have the camera on a tripod). A shade speed of 1/30, for instance, will let in twice as much light as a speed of 1/60 since it is two times slower. When you diminish the screen speed by a factor of two you are expanding the measure of light by "one stop"
