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Crop Factor & EFL Calculator

Science & Engineering

Sensor crop factor, equivalent focal length and FOV

Quick Answer

Crop Factor & EFL Calculator: Sensor crop factor, equivalent focal length and FOV. Crop Factor & EFL Calculator uses standard science & engineering formulas to compute accurate results instantly.

Sensor & lens

mm
f-stop
Full-frame equivalent (APS-C Sony/Nikon/Fuji 23.6×15.6)76.5 mm

Crop factor 1.53x · equivalent aperture f/2.75 · diagonal FOV 31.6°

Calculation

  1. 1Diagonal = √(23.6² + 15.6²) = 28.29 mm
  2. 2Crop factor = 43.27 ÷ diagonal = 1.529x
  3. 3EFL = 50 × 1.529 = 76.5 mm (FOV 31.6°)
  4. 4Equivalent aperture (DoF) = f/1.8 × 1.529 ≈ f/2.75
Crop factor = full-frame diagonal 43.27mm ÷ sensor diagonal (by diagonal, not area). A 50mm lens acts like 75mm on APS-C (1.5x), 100mm on M4/3 (2x), and wider ~40mm on medium format (0.79x). EFL unifies field of view only; equivalent aperture follows the DoF/total-light convention. Focal length never changes - only the framing does.

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How to Use

  1. Enter known quantities: fill values and confirm units in the Crop Factor & EFL Calculator.
  2. Instant solution: unknowns solve live with the formula shown transparently.
  3. Use constant/material tables: standard physical constants and material data are listed on this page.
  4. Compare conditions: change inputs to compare scenarios.

Key Points

  • Crop Factor & EFL Calculator is a free online science & engineering tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: Sensor crop factor, equivalent focal length and FOV.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Crop Factor & EFL Calculator formula

Crop Factor & EFL Calculator uses standard science & engineering formulas to compute accurate results instantly.

FAQ

How do I use the Crop Factor & EFL Calculator?
Open the page and fill in the input fields — results update automatically. Sensor crop factor, equivalent focal length and FOV.
Are the results accurate?
Yes. Standard formulas and conversion factors are used and verified.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required.
Does it work on mobile?
Yes. The responsive design works on phones, tablets and desktops.
Is my data saved?
No. Everything runs locally in your browser.

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Source & Updates

Based on CODATA recommended constants and standard physics formulas. Last updated: 2025-07

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Crop Factor & EFL Calculator[EB/OL]. https://www.yijiansuan.com/en/c/science/crop-factor

Results provided by this tool are for reference only and do not constitute professional advice.