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Eff. focal length

Calculate Eff. focal length instantly with the exact formula and a worked example. Free online calculator — no signup.

Eff. focal length

Focal, mm
Teleconverter
Eff. focal length
70mm
Calculate Eff. focal length instantly with the exact formula and a worked example. Free online calculator — no signup.

More about: Eff. focal length

What it calculates

The “Eff. focal length” calculator computes Eff. focal length in mm from 2 parameters: focal, mm, teleconverter.

Used by photographers and videographers when setting up a shoot.

Example calculation

With parameters Focal, mm = 50, Teleconverter = 1.4 the result is 70 mm.

How to use

  1. Enter the parameter values — every field above is adjustable with a slider.
  2. The result and related metrics are calculated automatically as you type.
  3. Use the additional metrics shown (if any) where needed.
  4. Copy the result or bookmark the page.

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