Understanding Shutter Speed

Shutter Speed is one of the three pillars of photography, the other two being ISO and Aperture (which is already discussed in earlier blog). Shutter speed is where the other side of the magic happens – it is responsible for creating dramatic effects by either freezing action or blurring motion. In this article, we will try to understand everything about shutter speed in very simple language.

What is a Camera Shutter?

Before reading this article, it is highly recommended reading about what a DSLR is and what it consists of. Simply put, a camera shutter is a curtain in front of the camera sensor that stays closed until the camera fires. When we hit the click button, the shutter opens and fully exposes the camera sensor to the light that passes through the lens aperture. After the sensor is done collecting the light, the shutter closes immediately, stopping the light from hitting the sensor. The button that fires the camera is also called “shutter” or “shutter button”, because it triggers the shutter to open and close.

What is Shutter Speed?

Shutter speed, also known as “exposure time”, stands for the length of time a camera shutter is open to expose light into the camera sensor. If the shutter speed is fast, it can help to freeze action completely. If the shutter speed is slow, it can create an effect called “motion blur”, where moving objects appear blurred along the direction of the motion. This effect is used quite a bit in advertisements of cars and motorbikes, where a sense of speed and motion is communicated to the viewer by intentionally blurring the moving wheels.

Slow shutter speeds are also used to photograph waterfalls or other objects at night or in dim environments with a tripod. Landscape photographers intentionally use slow shutter speeds to create a sense of motion on rivers and waterfalls, while keeping everything else in focus. Motion can also be frozen to an extent with a camera flash, even at low shutter speeds. 

How Shutter Speed is measured?