In simple terms, exposure in photography is the amount of light, you as a photographer, allow to reach camera sensor or film. Exposure determines how bright or dark your photographs appear.
How important is exposure in photography?
What are the components of exposure?
What is the “Exposure Triangle”?
The exposure triangle is a common way of associating the three variables that determine the exposure of a photograph.
It uses three interconnected photography components - ISO, Aperture and Shutter Speed.
THE IMAGE SENSOR
The image sensor or camera sensor is located in the body of the camera. It is the sensor that detects the light and records it to create your image. The sensor measures the intensity of light hitting the sensor as the shutter opens. The sensor is made up of individual units, which are called pixels. Each pixel measures the intensity of light by detecting the number of photons that reach the pixel. This information is relayed to the camera as a voltage value which can then be recorded by the camera.
ISO
ISO is a photographic concept that originated in film photography but was later translated to digital cameras too. However, ISO works in different ways in both types of photography.
ISO in Film Photography
In film photography, ISO is a number that defines how sensitive to light a particular roll of film is. Lower ISO numbers like 50 or 100 mean the film is not very sensitive to light. These types of film are perfect for shooting on a bright and sunny day outside. Analogically, higher ISO numbers mean films that are more sensitive to light. They are suitable for shooting indoors or in low-light conditions outside.
It’s a well-known fact that less sensitive films produce better quality photographs. This is due to their emulsion.
As you know, the emulsion of a film consists of light-sensitive layers of silver halide crystals that capture light. The higher the ISO, the larger and coarser these crystals are. They need to be such in order to record light more quickly and allow for using faster shutter speeds. However, they also create more grain. Lower ISO films, on the other hand, have emulsion with a finer crystal structure so they produce smoother photographs.
ISO in Digital Photography
“Lower equals smoother” is a rule that you can follow even if you only shoot digital. In digital photography, the ISO value can be changed very easily from the menu (you do not need to change films which is what film photographers do to increase or decrease light sensitivity). Depending on the model of your digital camera, you may have a choice of ISO ranging from 50 up to 409,600.
On a bright day outside ISO 100 is usually a great choice. But as the day advances, you’ll need to increase it to 200 and then 400 or more. If you shoot indoors, you will usually have to choose an ISO up from 200-400.
It’s important to know, though, that you never make your sensor more or less sensitive to light by choosing higher or lower ISO. Your camera always captures light at ISO 100. Then, depending on the ISO value you’ve selected from the menu, it increases its brightness.
Related: How to Take a Photograph with a Blurred Background
For example, if you’ve selected ISO 200, it will increase the brightness of your photo twice. If you have selected ISO 400, you’ll increase it three times and so on. In digital photography, this is called “gain”.
Just like in films, lower ISO settings produce images of better quality. That’s because the more our camera increases the brightness of the photo to match the high ISO we’ve selected, the
Just like in films, lower ISO settings produce images of better quality. That’s because the more our camera increases the brightness of the photo to match the high ISO we’ve selected, the more noise it creates. Colors also suffer at high ISO settings. They don’t appear as saturated as at lower ISO settings.
There’s nothing to worry about at ISO up to 800 but after that, the quality of the image begins to gradually worsen. (This is strictly camera-specific, so some cameras can produce more noise at ISO 800 than others.)
So, if you can shoot with a lower ISO. But compared to Aperture and Shutter Speed, ISO is the least creative component of the triangle. It only affects the brightness and general quality of the image but it doesn’t change the way your object looks like dramatically.
A change in aperture or shutter speed, on the other hand, may produce a brand new picture.
APERTURE
