Understanding how your shutter actually works, makes photography so much easier!
Most people assume the obvious, fast shutter = sport! Thats not entirely true throughout photography, but lets take a look.
What is Shutter Speed?
Shutter speed is a setting controlled on your camera, that allows you to adjust the time that the shutter “door/curtain” opens for, to expose the sensor in your camera.
Shutter is measured by Shutter Speed which is measured in seconds.
Eg: 1/250sec, 1/30sec, 1/3200sec and so forth
The value to which you can set the shutter speed is determined by your camera. Some cameras go higher than others, but generally all your shooting is done in the standard range.
A fast shutter speed is 1/3200
A slow shutter speed is 1/10
1/1 = 1 second, 1/2 = half a second, 1/100 = 1 hundredth of a second...you get the picture :)
Now how does it physically work?
This will make your brain understand the above much better.
Here is a quick little video on how your shutter actually works.
Its that basic, the mirror moves up, the first door opens, exposing your sensor to the light/picture through the lens, it then closes after the set amount of time. This is why if you leave it open too long (after shooting indoors) your picture is blown out and white when you walk outside with the same setting. (you would need to adjust your ISO and Shutter accordinly)
So...the faster the shutter speed (ie the higher the shutter number) the less light the camera will let in onto the sensor.
A fast shutter will freeze objects in motion.
The slower the shutter speed (ie the lower the shutter number) the more light the camera will let in onto the sensor.
A slow shutter will blur objects in motion.
Therefore to capture/freeze something in motion, you must use a high shutter speed. (ie. insure good light conditions)
To let more light in, a slower shutter speed is needed. (ie. this is good for poor lit conditions)
Remember, a fast shutter will always provide a much sharper image.
As a rule of thumb, never shoot under 1/150 or 1/100 unless you have an extremely steady hand.
However, if you are using a longer lens, and shooting above 120mm try to make sure your shutter speed is 1/400 and up to ensure pin sharp images.
Here is a classic example of a fast shutter speed taken mid day with more than enough light.
This is a great example of a slow shutter speed taken with a little bit of flash to create some form of movement on the dance floor at a wedding.
If you have any questions, drop them in the comments below...I'd love to help.