Focal Length & Field of View Calculator
Which lens gives the frame you drew, from the distance the location actually allows. The calculator above takes sensor, focal length and distance and returns horizontal field of view, vertical field of view and frame width at distance — computed in your browser, with no sign-up and nothing leaving your device.
Focal Length & Field of View Calculator
- Horizontal FoV
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- Frame width
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- Frame height
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Runs entirely in your browser — no sign-up, nothing transmitted.
What the number actually depends on
A 50 mm on Super 35 sees 25.4° horizontally; on full frame the same lens sees 39.6°.
At 3 m distance, a 35 mm on Super 35 frames 2.1 m of wall — enough for a two-shot, not for three.
The gap between a number that goes into a quote and one that holds on the day is rarely the formula — it is whether the constraints were entered honestly. That is why the inputs are spelled out below.
Common mistakes
The places where the arithmetic is right and the day still falls over:
- Scouting a location without measuring the maximum camera-to-subject distance
- Assuming a full-frame lens list transfers to a Super 35 body
In day-to-day production
Crop factor changes field of view, never perspective. Perspective is set by camera distance alone.
The number belongs in pre-production — the point where a decision is still free to change. Working it out on the shoot day is no longer calculating; it is finding out.
In TillyGen this is not a separate step: the result sits inside the plan itself, alongside the shot list, schedule and call sheet. Change a constraint and the dependent values move with it — the affected parts of the plan are flagged rather than quietly left behind.
Frequently asked
How accurate is the Focal Length & Field of View Calculator?
The maths is exact; the inputs rarely are. Treat the result as a solid floor and add your buffer deliberately rather than smuggling it into the inputs — a flattered input hides the buffer from everyone who plans with it later.
Is the calculator free?
No. It runs entirely in your browser, with no sign-up and nothing transmitted. There is no usage limit and no account.
Where does this fit in production planning?
In pre-production. There it is a basis for deciding; later it is only a finding.
Can I export the result?
The calculator itself only displays the value. In TillyGen it lands directly in the shot list, schedule and call sheet, and goes out as PDF, CSV or through the API to everyone working from it.
What does the calculator return?
Horizontal field of view, vertical field of view and frame width at distance. The first value is the one you carry into the plan; the rest show how sensitively it reacts to the inputs.
What should I watch for in the result?
Mainly this: scouting a location without measuring the maximum camera-to-subject distance. That is the mistake that most often turns a correctly calculated number into one that does not hold.