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.