Shutter speed = Exposure time.
Why use a particular shutter speed?
Slower shutter speed lets in more light
Faster Shutter Speed lets in less light
Slower shutter speed blurs motion
Faster shutter speed freezes motion
General guidance to minimum speed for sharpness
1/1000 Birds in Motion
1/500 People walking or running
1/250 Fish swimming in water
1/60 Street scene with casual movement
1/30 Panning shot with background blurring
1/15 Blurring moving hands and feet
1″ Blurring waterfalls and streams
30″ Nighttime photography
A setting where you determine the exposure by how long you hold the shutter button.
Often used for light painting.