The Importance of Shutter Speed & Shutter Angle

On cameras and camcorders the shutter is the device that controls the amount of light that can pass through a lens. Shutter can be described in terms of fractions of seconds or angle. What exactly is a camera shutter? What’s the difference between shutter speed and shutter angle? For better understanding, it is recommended that you get yourself familiarized with the related terms.

What is a Camera Shutter?

The shutter is a covering for your camera sensor that is kept closed until you capture a photo or record a video. Every time the camera takes a shot, the shutter opens allowing the sensor to be exposed to the light that goes through the camera lens’ hole or the aperture. The shutter closes once the sensor grasps the light in order to stop the light to hit the sensor.

What is Shutter Speed?

Shutter speed is the time that is measured when the camera shutter is open. This is the definition with regards to still photography. When it comes to film photography, shutter speed is the time that is measured of the film’s exposure to the scene that is being recorded.

Shutter speed in digital photography is the time that is measured for the camera’s sensor image to see the scene that is going to be shot. Technically, it is the time when dramatic effects are created either when you blur the action or freeze it.

What is Shutter Angle?

The term “shutter angle” is used to describe the shutter speed that is relative to the frame rate. Shutter angle is generally used for rotary shutters where a disc containing the angled opening spins and lets in light once per revolution to expose every frame. The shutter speed is lower when the angle is larger. The limit is up to 360°, which is the point where the shutter speed becomes as slow as the frame rate. Decreasing the angle makes shutter speed arbitrarily fast.

The Primary Difference Between Shutter Speed & Shutter Angle

The primary difference between shutter speed and shutter angle is how they are both measured. Shutter speed is measured in fractions of a second. Shutter speed measures how fast the shutter moves. For example, if the shutter exposes the film for 1/60th of a second, then it means it has 1/60 shutter speed. Slow shutter speeds allow more light but if the subject is moving, then the image is produced with motion blur. On the other hand, faster shutter speeds allow less light but they are effective when it comes to freezing motion.

Shutter angle is measured in degrees. When you measure shutter angle, you are measuring the part of the rotary disc that is exposing the film to the light. A shutter angle is considered “normal” if it is 180 degrees. At this angle, the shutter speed is half the frame rate. For a film shot at 24 fps, the standard shutter angle is 180 degrees.

Overview

In the digital realm, the terms shutter speed and shutter angle are used interchangeably. DSLR cameras refer to exposure time with the term shutter speed while CMOS shutter-less cameras generally refer to it as the shutter angle. The key difference between the two is the way they are both measured.