Enter the aperture (f-stop) and the wavelength of light to calculate the diffraction limit of a lens. The diffraction limit determines the resolution capability of the lens.
Lens Diffraction Formula
The following formula is used to calculate the diffraction limit of a lens:
DL = 2 * λ * 1000 * √(1 + A^2)
Variables:
- DL is the diffraction limit (micrometers)
- λ is the wavelength of light (micrometers)
- A is the aperture (f-stop)
To calculate the diffraction limit, multiply the wavelength by 2, then by 1000, and finally by the square root of 1 plus the aperture squared.
What is Lens Diffraction?
Lens diffraction is a phenomenon that occurs when light waves encounter an obstacle or aperture, such as the blades of a camera lens. As light passes through a small aperture, it spreads out, causing the image to lose sharpness. This effect limits the resolution of the lens and is most noticeable at small apertures (high f-stop numbers). Understanding the diffraction limit helps photographers and optical engineers optimize image quality by balancing aperture size and the resulting depth of field with the sharpness of the image.
How to Calculate Lens Diffraction?
The following steps outline how to calculate the Lens Diffraction Limit.
- First, determine the wavelength of light (λ) in micrometers.
- Next, determine the aperture (f-stop) of the lens (A).
- Next, gather the formula from above = DL = 2 * λ * 1000 * √(1 + A^2).
- Finally, calculate the Diffraction Limit (DL) in micrometers.
- 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.
Wavelength of light (λ) = 0.55 micrometers
Aperture (f-stop) of the lens (A) = 8
