Aperture Area Calculator

Your details

Choose which value to calculate. The other fields become your inputs.
All length inputs and outputs use this unit. Area is shown in the squared equivalent.
The diameter of the circular opening through which light passes.
mm
The distance from the lens (or mirror) to the focal point, in the selected unit.
mm
The dimensionless ratio of focal length to aperture diameter (e.g. 1.4, 2.8, 4).
Aperture area
1,963.5

Light-collecting area of the circular opening

Area unitmm²
Aperture diameter50
Focal length70
f-Number1.4
Aperture radius25
Relative light vs f/1.41

Aperture area: 1963.50 mm²

  • The aperture diameter is 50.00 mm, giving a light-collecting circle of 1963.50 mm².
  • An f-number of 1.40 is closest to the standard f/1.4 f-stop. Each full stop halves or doubles the aperture area.
  • This aperture gathers roughly the same light as an f/1.4 lens at the same focal length.
  • A larger aperture area lets in more light, brightening the image and enabling faster shutter speeds or lower ISO, but it also reduces depth of field.

Next stepUse the f-stop reference table below to compare how different f-stops trade off light-gathering ability against depth of field.

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