For a long time now I have been thinking to write on this. It's not rocket science, it's pretty easy to understand. The photography scholars explain exposure as a triangle that helps us to make required amount of light travel to the Image Sensor to capture good exposed pictures. The three edges of the exposure triangle are:
1. Shutter Speed
2. Aperture
3. ISO
One essentially has to mention the above three, when one intends to include or share the EXIF (Exposure Information). One has to have a balance between the three to take correctly exposed pictures. If you take a picture in bright sunny day and you realize that it has come too dark or too bright, then your picture is under or over exposed respectively.
Lets understand all the angles of the Exposure edges in brief:
Shutter Speed
It is the measurement of time for which the shutter is open while taking a picture. It is usually measured in seconds or fraction of second. For eg. 10sec, 1/240sec, 1/2sec.. Shutter speed is also known as Exposure Time. Higher the exposure time or slower the shutter speed, more the light falling on the sensor.
Aperture
It is the measurement of diaphragm of the lens. It is measured as f-stops. For eg. f/5.6, f/1.8, f/16. Higher the f number, smaller is the opening and vice versa. The smaller the opening (Higher the F number) less amount of light travelling through the lens.
ISO
It is the measurement of sensor's sensitivity to light. Higher ISO means sensor is more sensitive to light. While Shutter Speed and Aperture helps to control the amount of light coming into the camera, ISO helps to determine how much light is needed by the sensor for good exposure. Taking images with higher ISO than required, produces noise in the image, that is why it is recommended to take pictures at lowest possible ISO levels. If you double the ISO (for example, from 200 to 400), the camera needs only half as much light for the same exposure. So if you had a shutter speed of 1/100 at 200 ISO, increasing the ISO to 400 will let you get the same exposure at 1/200 second (with Aperture unchanged).
All three are the settings to control the amount of light travelling to the sensor. One can master to maintain a balance between the three and capture good exposed pictures with practice.
Happy Clicking!!
*Image Credit :Altermundus.com
