The Exposure Triangle in Photography

To create a photograph we need light. To get the light at the right exposure, you need to adjust three settings on the camera: aperture, shutter speed (shutter speed) and ISO. The purpose of using these settings is to find the right balance of light, depth of field and focus. While there are basic principles for finding the right combination, there is no single formula to follow. The important thing is to understand how these elements should be used together so that you can achieve your own creative results.

Depth of Field

Depth of field is how much of your image appears sharp, determined by the aperture. At high depth of field, most of the image is in focus, and this is achieved with a small (small) aperture value such as f/22. At low depth of field, only part of the image is sharp and the out-of-focus part is blurred in proportion to the aperture value. Open aperture values (such as f/1.2) blur the area behind the subject in focus. So there is an inverse relationship between aperture and depth of field. Basically, larger apertures produce narrower depths of field, so if you want to take a photo with a blurred background, you need to widen the aperture. But other factors also play a role. Lenses with longer focal lengths allow you to achieve smaller depths of field (e.g. the F2.8 aperture in a 100mm lens is much larger than the F2.8 aperture in a wide-angle 24mm lens, so the background will be blurrier).

To create a photograph we need light. To get the light at the right exposure, you need to adjust three settings on the camera: aperture, shutter speed (shutter speed) and ISO. The purpose of using these settings is to find the right balance of light, depth of field and focus. While there are basic principles for finding the right combination, there is no single formula to follow. The important thing is to understand how these elements should be used together so that you can achieve your own creative results.

The English word "exposure" is used to describe the amount of light a photograph receives. When the photosensitive surface receives the right amount of light, the result is a correctly exposed photograph. When it receives less than the required amount of light, an underexposed image is produced, and when it is exposed to more than the required amount of light, an overexposed image is produced, which we refer to as an exploded image.

The mechanism in the lens that controls the amount of light that enters the camera and reaches the sensor is called the aperture. In most lenses, the largest aperture is F/1.2 and the smallest is F/32. Each value lets half as much light through to the sensor as the previous value. The largest aperture is written on the lens as a value divided by 1, such as 1:2.8. While the largest aperture of some lenses is fixed, the largest aperture of some zoom lenses varies depending on the focal length and is indicated by two aperture values such as 1:4-5.6.

Shutter speed refers to how long the shutter in front of the sensor opens and closes. A fast shutter speed allows you to freeze the moment and shoot with the camera in your hand (usually 1/125 and faster values).Slow shutter speeds allow us to get better exposed photos with the shutter open longer in low light conditions, while the slightest movement in the camera can cause shaking in the photo, making it necessary to use a tripod. Shutter (shutter speed) values are expressed in seconds. The values we can set on current cameras can be a maximum of 30 seconds, while the lowest can be 8000th of a second.

ISO Value;

ISO is the value that shows the sensitivity of the sensor to light. The maximum ISO setting may vary in each camera, but can range from 100 to 12800. The lower the ISO value, the less light sensitive the camera is, which means that we will need more light from outside for correct exposure. In low light conditions where we cannot interfere with the shutter speed and aperture speed, we can increase the ISO value to get correctly exposed images, but this requires us to sacrifice the quality of the photo, because at high ISO values we will get a sandy image in the photo, which is called noise or gran in English. When we balance these settings, which you can see at each end of the triangle above, we get an ideal, correctly exposed photo.