Anyone who has taken up photography will quickly run into two terms when they discuss or read about the correct way to expose a photograph, and those terms are “aperture” and “f stop”. While they sound different, they are actually the same exact thing.
What is aperture? It translates to the part of a lens that dictates how much light is let through to the camera’s sensor – when it is wide open, lots of light gets through. When it is closed down, not much light gets through. The aperture is adjusted through the camera’s f stops, which are discussed as decimals and work in a sort of inverted fashion. This means that the smaller the f stop number the larger the aperture, and vice versa.
Understanding f stops is important for making the proper exposure for the desired results. While there are charts and tables with f stops recommendations for a photographer to follow, it is best to understand the various needs of any type of photography and also what the right settings should be to get the desired results.
For example, it is vital that a photographer has an understanding of aperture and shutter speed, because they cannot work independently of one another. Aperture controls the depth of field in the photograph and it controls the amount of light on the sensor. This means that if the aperture is small, which also means a higher f stop, the shutter speed is going to have to be slower to allow in enough light.
There are no standard aperture and shutter speed settings that photographer can apply to specific photographic scenarios, and this is the reason that photographers will use two different approaches to photography in which the aperture is a significant factor.
Let’s use the example of a small statue set along a walkway. A photographer will want the subject to be the statue, and not the foreground or background. To limit the depth of field for the subject, they will open the aperture wide and cause the foreground and background to be blurry. Where they might get confused is in the correct shutter speed settings, but this is easily overcome by the use of the aperture priority setting on the camera. This simply allows the user to dial in the desired f stop and the camera chooses the appropriate shutter speed. This is opposite of the shutter priority mode, which might not use true aperture and works directly in connection with the shutter settings.
What is true aperture? This is the mechanical setting that a camera, in any mode other than aperture priority, might use to create an image, but is often not the f stop displayed. For example, a camera in a landscape mode might indicate an f stop of 15, when in fact the camera is capable of only using an f/11 in the image.