How to use
- Enter the active sensor width and height in millimetres. Use the dimensions actually recorded by the selected photo or video mode, including any crop.
- Enter the lens’s actual focal length in millimetres, not the full-frame equivalent printed in some phone specifications.
- Enter the distance in metres from the ideal projection centre to the flat subject plane, measured along the optical axis. Calculate to display all three angles and field dimensions.
The initial values are editable examples, not detected camera settings. Enter plain numbers with a decimal point or decimal comma and without thousands separators. The range below each field states the supported limits. Press Calculate, or Enter in a field, to confirm the current inputs. The diagram above the fields updates immediately with valid settings, including the starting example. Editing clears the confirmed Result and Copy state; press Calculate to confirm again. Incomplete or invalid settings remove the preview geometry. Clear empties the numeric inputs, result and diagram; it keeps the calculation selection. Copy result copies the displayed values with labels. Calculations stay in your browser. Changing the site language opens a translated page and asks before leaving your current inputs; it does not convert a saved camera configuration.
Calculation and interpretation
This field of view calculator helps you estimate whether a subject will fit in a frame before choosing a lens or shooting position. Horizontal angle describes the left-to-right view, vertical angle describes top to bottom, and diagonal angle runs between opposite corners. These are full angles, not half angles. The output width and height describe a plane perpendicular to the optical axis, rather than a curved surface or a sloping wall.
For a sensor dimension a and focal length f, angle = 2 × atan(a / (2f)). Convert radians to degrees for the displayed angles. The diagonal sensor dimension is √(width² + height²). Field width at distance D is D × sensor width / f, with the same relation for height and diagonal. Sensor dimensions and focal length are both in millimetres, so their ratio is unitless and the field dimensions remain in metres.
The diagram is a horizontal cross-section: A is the projection centre, B is the subject plane, and the two rays bound the field width. Labels give the confirmed distance, angle and width. It is a planning schematic rather than a drawing of the camera’s internal lens elements. Increasing distance changes the field size but does not change the angle in this model.
Worked examples
With a 36 × 24 mm sensor, a 50 mm lens and a distance of 3 m, the horizontal angle is 39.60°, the vertical angle 26.99° and the diagonal angle 46.79°. The covered plane is 2.16 m wide and 1.44 m high. This is a useful first estimate for arranging a small group or a product backdrop.
Keep the same sensor and lens but move the plane to 6 m. Width becomes 4.32 m and height becomes 2.88 m, while all three angles remain unchanged. Alternatively, a 100 mm lens at the original 3 m distance gives a 1.08 × 0.72 m field: doubling focal length halves the plane dimensions in this approximation.
Practical uses and limits
Use the result for framing estimates, backdrop planning and comparing lens coverage. Leave some practical margin for levelling, stabilisation crops, distortion correction and final trimming. A camera specification such as ‘1-inch type’ is a naming convention, not a one-inch sensor diagonal; obtain the actual active dimensions from reliable specifications.
The formula assumes rectilinear projection with focal length referenced to infinity focus. A real lens focused nearby can change effective coverage through lens extension or focus breathing. Thin-lens geometry is an approximation, and this tool does not model macro magnification, fisheye projection, distortion, lens shift or internal focusing. Distance must exceed focal length expressed in metres; even a valid short distance is not a promise of close-focus accuracy.
Frequently asked questions
Why must I use actual focal length?
Equivalent focal length already includes a sensor comparison. Combining that value with the smaller sensor applies the crop twice and predicts an incorrectly narrow view.
Does a longer shooting distance widen the angle?
No. With sensor size and focal length fixed, angle stays the same. The same cone intersects a larger plane farther away, so the covered width and height increase.
Can I use this for video?
Yes, if you know the active video sensor area. Stabilisation, aspect-ratio changes and high-frame-rate modes may record only part of the physical sensor.
Why does my photograph differ?
Check actual focal length, active crop, distance reference and plane orientation first. Lens distortion, focus breathing and close focusing can cause additional differences that this ideal model cannot correct.