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Shutter Speed - Exposure Triangle Part 1

Updated: Jul 25, 2018

There are three components which determine exposure – Shutter Speed, Aperture, and ISO. Exposure triangle is the relationship of all these three components. There is no right or wrong ratio of these three components. Correct exposure is determined based on the ambient lighting and the purpose of the photograph. We will explain all three in detail in three different parts. In this article, we try to explain shutter speed.


Shutter performs the typical job of any shutter, closing, and opening to allow something in or deny something in. In the case of a camera, shutter decides whether to allow or deny the "light" to enter. How long the shutter is open is the decision which a photographer need to make. As you all know there is a digital sensor in our cameras (know more about Sensors), a shutter is what determines how much light digital sensor is receiving and for how long.

The duration for which shutter is open is called shutter speed. The longer the shutter remains open, more the light is allowed in and shorter the shutter remains open, less the light is allowed. The shutter can open for as long as you want (BULB Mode) or it can open for a very short period of time, for example, 1/8000th of a second. You have complete control over it. All you need to do is dial a button in your camera and set the desired speed. To get a properly exposed photo, you need to have right amount of light; and shutter determines how much light it enters the camera (or sensor) but that does not mean you can have a properly lit photo by adjusting just shutter speed because remember what we mentioned before, exposure is the function of all THREE variables – Shutter Speed, Aperture, and ISO.

Some basic terminologies related to shutter speeds are when someone says shutter speed is too “slow” or t