Chapter 4: Camera Settings, Aperture & F-Stop

The

F-Stop setting determines
• Determines how much light is allowed to enter athe camera through the lens to reach the imaging sensor.sensor and measured in F-stopStop. is normally a setting of the lens that is attached to the camera, andThis is controlled mechanically, by opening or closing the lenscamera aperture.

  Different lenses have different aperturesapertures, and so can handlehandling different f-stop ranges. Aperture also determines the Depth of Field. 

• Lower f-stop numbers indicate that the aperture is more open, allowing in more light. Lower f-stop numbers also narrow the depth of field, causing the area of focus to be relatively shallow, with foreground and background parts of the image being out of focus.
• Examples:
  • f/1.2 - f/2.8 - lets in a lot of light; shallow depth of field
  • f/4 - f/8 - useful in many scenarios; somewhat wider depth of field
  • f/11 - f/32 - best for bright settings; wide depth of field
• The “depth of field” is the distance between the nearest and furthest in-focus objects in an image. A narrow depth of field will have a very narrow area in which objects will be in focus. A wide depth of field will put most elements of the image in focus. Turning the focus ring will adjust the position of the in-focus area, or focal point.
  

The Canon EF 24-105mm f/4L IS II USM lens that is normally kept on the SCiL DSLR cameras has an adjustable f-stop rangefrom f/4 (wide open) to f/22 (nearly closed). It will retain the f-stop you set through its entire zoom range from 24mm to 105mm.

When the camera is set to video mode, you can set the f-stop on the Canon EOS 5D Mk IV using the large dial around the "set" button located at the lower right of the camera body.

Lower f-stop numbers (like f/4) indicate that the aperture is more open, allowing in more light.

Higher f-stop numbers (like f/22) indicate that the aperture is more closed, allowing in less light.

F-stop settings influence the depth of field.

f/1.2 - f/2.8 - lets in a lot of light, with a correspondingly shallow depth of field.

f/4 - f/8 - useful in many scenarios, with a somewhat wider depth of field.

f/11 - f/32 - best for bright settings, with a wide depth of field.

In the chart below, see how different f-stop settings change the amount of light reaching the sensor and the depth of field: