Shutter Speed

Shutter speed is the time while the shutter curtain is open, exposing the sensor to light. Don’t worry, there are no frightening F-numbers here :-). Shutter speed is measured in normal seconds. At bright day light, we usually use hundredths of a second. When cloudy, in shade etc., might be tenths of a second. At night it comes to full seconds.
While the shutter is open, the sensor records everything it sees. It does not realize what the objects are, it just divides the scene into millions of dots and records the color of every dot during the exposure time. Imagine that it is quite dark, and we are shooting a moving car at the shutter speed of 1 second. With the speed of only 50 km per hour, the car will move by almost 14 meters during this time. The sensor will see the car at the initial position at the first moment. Then the car will move to a place where the sensor previously saw only the background, and the sensor will now see only the background at the car’s initial position. And so on until the final car position. What will be on the resulting photo? A 14-meters long semi-transparent car! 🙂
The car we obtained is not sharp, it has what is called motion blur. The motion blur is the result of shooting moving objects with long shutter speeds. This is the shutter speed side-effect you should always keep in mind. If you want to get a sharp object, make sure the shutter speed is fast enough to freeze its motion. If you want to get a motion-blurred object to emphasize the movement, make sure the shutter speed is slow enough.