Camera / Optics
Required Focal Length Calculator
Work backward from a subject’s desired field of view to the exact focal length you need, on any sensor size and with any anamorphic squeeze factor, live as you type.
Sensor & Framing
Reference
Work backward from a target field of view to the focal length that delivers it — useful when you know how much of a scene you need to cover but not which lens gets you there.
With an anamorphic squeeze, the lens captures a wider horizontal field of view than a spherical lens of the same focal length, because the image is optically compressed before it reaches the sensor. Vertical framing is unaffected by squeeze.
Results
Working Backward From Field of View to Focal Length
Most lens calculators start with a focal length and tell you the field of view it produces. This one runs the math the other direction: tell it how much of a scene you need to cover, in degrees, and it returns the exact focal length that gets you there on your sensor — useful when you’re planning a shot list before you’ve picked a lens, or scouting a location and need to know if your kit can cover it.
Horizontal, Vertical, or Diagonal
Field of view can be measured along any of three axes, and they don’t scale together on a non-square sensor. Horizontal FOV is the most commonly quoted spec and the most useful for framing width across a scene; vertical FOV matters more for portrait orientation or ceiling-to-floor coverage; diagonal FOV is mostly used for wide-angle and fisheye lens specs. Pick whichever axis matches the constraint you’re actually solving for.
Anamorphic Squeeze
Anamorphic lenses optically compress the image horizontally before it hits the sensor, which means a given focal length captures a wider horizontal field of view than the same focal length on a spherical lens. A 2.0× squeeze effectively doubles the horizontal coverage without changing the vertical. This calculator factors your squeeze ratio into the horizontal-FOV solve so the required focal length accounts for it correctly.
This tool is especially useful for:
- Directors and DPs planning coverage before choosing lenses for a scene.
- Location scouts checking whether a space can be covered from a given camera position.
- Anamorphic shooters solving for focal length while accounting for squeeze ratio.