Three Pillars ofPhotography
Three Pillars of Photography
• Aperture
• Shutter Speed
• ISO (film speed)
Aperture• What is Aperture?
• A hole within a lens through which light enters a camera body.
• The aperture of a camera lens operates like the pupil of a human eye.
• The larger the pupil the more light enters the eye. The smaller the pupil the less light enters.
• Small Pupil = Large f-stop number
• Large Pupil = Small f-stop number
Aperture as F-stop
• F-stop number is the ratio of focal length to effective aperture diameter. To determine a camera's f-stop you need to divide the camera lens diameter by its focal length.
• Focal Length: Distance from front of lens to camera sensor when subject is in focus.
• Focal length is stated in mm on the camera lens. A prime lens has a fixed focal length while a zoom lens shows a range of focal lengths.
F-stop continued
• A camera with a lens diameter of 50mm and a focal length of 10mm would be f5 because the ratio is 50/10.
• To change the f-stop would require a change in lens diameter by adjusting the aperture. 30mm diameter and focal length of 10mm would be f3 because the ratio is 30/10.
F-stop continued• A large f-stop number means a small
opening and lets in less light.
• A small f-stop number means a larger opening and lets in more light.
• An f-stop like f1.7 is referred to as "wide open" and is considered "fast" because it lets a lot of light into the camera and allows for a faster shutter speed.
Depth of Field• What is Depth of Field?
• It refers to the amount of an image that is in focus and is directly impacted by the camera's aperture.
• The smaller the aperture (represented by a large f-stop number like f14) the more of the image will be in focus.
• A larger the aperture (f1.7) isolates an object from its surrounding by making them blurry.
• This is referred to as a "shallow depth of field" and is a popular and effective photographic technique.
f1.7 f14
An example of a shallow depth of field.
Bokeh
• Pronounced "boh-kay", it refers to the aesthetic quality of blur in the out-of-focus parts of a photograph.
• Term originates from the Japanese word "boke" which means "blur" or "haze".
An example of course bokeh and shallow D.O.F.
You've just learned about aperture, f-stop, focal length, depth of field, and bokeh.