Enter the focal length (mm) and the crop factor into the Calculator. The calculator will evaluate the Equivalent Aperture.

- Numerical Aperture Calculator
- Resolving Power Calculator
- Aperture Area Calculator
- Crop Factor Calculator

## Equivalent Aperture Formula

EA = FL * CF

Variables:

- EA is the Equivalent Aperture (in)
- FL is the focal length (mm)
- CF is the crop factor

To calculate Equivalent Aperture, multiply the focal length by the crop factor.

## How to Calculate Equivalent Aperture?

The following steps outline how to calculate the Equivalent Aperture.

- First, determine the focal length (mm).
- Next, determine the crop factor.
- Next, gather the formula from above = EA = FL * CF.
- Finally, calculate the Equivalent Aperture.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

focal length (mm) = 3.25

crop factor = 3