This week we learned about basics of Digital Photography: Aperture, Shutter Speed & ISO.
Aperture is the opening through which lights enters the camera. It is measured in f-stops (f/4, f/8, f/22 etc.), and – which may be a bit confusing – the smaller the number behind the f, the larger is the opening. Aperture influences the Depth of Field (DOF), which is the area of the photograph which is in focus. The higher the DOF, the more of the image will be in focus.
In summary, a higher aperture (= smaller numbers in f-stops) results in a smaller depth of field, meaning fewer objects in focus! In contrast, a smaller aperture (larger f/x) means a larger depth of field and a wider area in focus.
Shutter Speed refers to the internal shutter of a camera which blocks out the light, and is defined as the amount of time in seconds that shutter is open. A fast shutter allows to capture fast movements (such as water splashing), while a slow shutter creates motion blur, so only the static parts of the image will be clear.
Fast Shutter Speed
Slow Shutter Speed
ISO measures the sensitivity to light, with a lower number meaning less sensitivity. So when photographing in a dark environment, a higher ISO setting may be appropriate.
Finally, Reciprocity is the understanding that all those three factors are involved in the effective exposure of the image. To understand this concept, it helps to visualize the camera as a window: The size of the window (aperture) controls how much light enters the room. However, light can only enter the room while the shutters are open (shutter speed). The effect of ISO can be understood as wearing sunglasses inside that room, thus being less sensitive to the incoming light.
Images Source: digital-photography-school.com. Unfortunately I couldn’t take example pictures on my own, as I currently do not have access to a camera with adjustable aperture/shutter speed.