Exposure
What is Exposure?
The Exposure Triangle - Changing the value of one element will require compensation from another.
Exposure is the total amount of light that is allowed to fall onto the cameras digital sensor or film.
There are three elements that make up an exposure:
Aperture: The size of the hole that lets light into you camera.
Shutter Speed: The amount of time that the shutter is open to allow light in.
ISO sensitivity: How sensitive the digital sensor or film in a camera is to light.
Past posts have been written about each of these elements and I strongly suggest you read about each one to get a good understanding of how they work.
Putting it all Together.
In order to achieve the right exposure each element needs to be balanced out, raise the shutter speed and you might need to use a wider aperture or a higher ISO to compensate. This is called the exposure triangle.
One way you can think of it is that a camera is like a bucket being filled with a garden hose.
There are three variables to consider,
The size of the hose and how much water it lets out (aperture)
The time that the hose is left running (shutter speed)
and the size of the bucket (ISO)
In order to achieve the right exposure the bucket needs to be filled to the very top, if its undefiled you will under expose and if you over fill you will over expose.
Taking a photo is like filling a bucket with water, you need to account for different variables to fill it up.
Say we want to use a fast shutter speed to take a photo of a moving object, well if we run the hose for a short period of time the bucket will not be filled to the top, so we need to compensate, we can use a hose that has a larger opening and lets more water out (open the aperture) or we can make the bucket smaller so that it gets filled quicker (raise the ISO)
It takes time to master exposure, but its necessary to have an understanding of how it works to achieve turning an idea into a great photo.
You need to understand how each of the elements work and how they effect each other.
For further reading to better understand the three elements of exposure check out some of our past posts:
