Field of View Calculator

Sensor format:

Custom lets you enter the exact active width and height from a camera specification.

Custom sensor size:

Use active image-area dimensions, not the nominal inch-type format.

W H mm

Frame orientation:

Match the orientation of the captured or delivered frame.

Focal length: {{ focalReadout }}

Enter the exact focal length; the slider provides quick tuning.

Subject distance: {{ distanceReadout }}

Changing units preserves the physical distance. Exact entry extends beyond the slider window.

Setup preset:

Choose a starting setup, then adjust any measurement.

Target frame width:

Use zero when you only need the angle and frame-size estimate.

Minimum sweep focal length:

Choose a positive value below the maximum sweep focal length.

Maximum sweep focal length:

Choose a value above the minimum, up to 1,200 mm.

Sweep samples:

Use 6 through 24 evenly spaced focal-length samples.

points

Measure	Value	Planning note	Copy
{{ row.label }}	{{ row.value }}	{{ row.note }}

Loading lens sweep…

Framing is a geometric relationship between the camera's active sensor, the lens focal length, and the distance to the subject plane. Change any one of those three and the scene covered by the frame changes. This matters when a room, person, product, inspection area, or distant subject must fit before the camera position is fixed.

Angle of view and field of view describe related but different quantities. Angle of view is the lens-and-sensor angle measured in degrees. Field of view is the physical width and height covered at a stated distance. A 74° horizontal angle has no single width until the subject distance is known.

Sensor dimension: A wider active sensor dimension captures a wider angle with the same focal length.
Focal length: A shorter focal length widens the angle; a longer focal length narrows it.
Subject distance: Moving farther away increases physical frame coverage without changing the optical angle.
Orientation: Portrait orientation swaps which sensor dimension controls horizontal and vertical coverage.

Sensor names alone can be misleading. “One-inch type,” APS-C, Super 35, and phone sensor labels may cover several actual dimensions. Active image width and height from the camera specification are better inputs than a nominal format name, especially when video modes crop the sensor.

Crop factor compares sensor diagonals with the 36 × 24 mm full-frame reference. It can translate a focal length into a full-frame-equivalent framing number, but it does not change the physical focal length engraved on the lens. Nor does equal framing guarantee equal depth of field, perspective, distortion, exposure, or image quality.

The basic geometry models a rectilinear lens and a flat subject plane. Real lenses can breathe while focusing, distort near the edges, or report a nominal focal length that differs slightly from the effective value. Close-up work also departs from the simple distant-focus model. Leave framing room when the shot cannot be checked at the actual location.

How to Use This Tool:

Start with the active capture area and the real camera-to-subject distance, then use the target check only when a required width must fit.

Choose Sensor format and Frame orientation; for Custom active dimensions, copy the active width and height from the camera specification.
Set Focal length in millimetres and Subject distance in a convenient unit. Distance is measured to the plane whose coverage you want to estimate.
Open Advanced for editable setup examples, a lens-sweep range and density, or Target frame width when a known scene or subject width must fit. Use zero to turn the target comparison off. Invalid optional target or sweep settings leave valid frame coverage available.
Read the current frame dimensions and angles first. Use Lens sweep to compare focal lengths at the same distance, keeping the sensor and orientation unchanged.

Interpreting Results:

Frame width and Frame height are the estimated physical coverage at the subject distance. The horizontal, vertical, and diagonal angles describe the optical cone and do not change when only distance changes.

Target fits includes at least 10% width margin. Tight target fit means the target fits with less than 10% margin. Target does not fit means the estimated frame is narrower than the target.
Required focal length estimates the longest focal length that would fit the target at the current position. Required distance estimates where the current lens would need to be placed.
Verify critical framing with the actual camera, capture mode, lens, focus distance, stabilization setting, and delivery crop before committing to a location or lens rental.

Technical Details:

Horizontal, vertical, and diagonal calculations use the corresponding active sensor dimension. All sensor dimensions and focal lengths use millimetres; physical coverage and target calculations use metres internally.

Formula Core:

For a rectilinear thin-lens model, sensor dimension and focal length determine angle of view. Projecting that angle to a subject plane gives the covered physical dimension.

\begin{aligned} θ & = 2 atan (\frac{S}{2 f}) \\ F & = 2 D \tan (\frac{θ}{2}) \\ f_{required} & = \frac{S D}{T} \\ D_{required} & = \frac{T f}{S} \end{aligned}

S is the active sensor width or height, f is focal length, θ is the matching angle of view, D is subject distance, F is physical frame coverage, and T is target width. Angles are converted to degrees for display.

Crop factor uses sensor diagonals. The full-frame reference diagonal is √(36² + 24²) mm.

\begin{aligned} c & = \frac{\sqrt{36^{2} + 24^{2}}}{\sqrt{W^{2} + H^{2}}} \\ f_{equiv} & = f c \end{aligned}

W and H are active sensor dimensions. Equivalent focal length communicates matching diagonal framing on full frame; it does not alter the lens.

Rule Core:

Target fit rules based on frame width divided by target width
Target result	Exact rule	Meaning
Off	Target width = 0	No fit comparison is made
Target fits	Frame width ÷ target width ≥ 1.10	At least 10% width margin
Tight target fit	1.00 ≤ ratio < 1.10	The target fits with less than 10% margin
Target does not fit	Ratio < 1.00	The frame is narrower than the target

Descriptive lens classes use diagonal angle: ultra-wide at 100° or more; wide from 75° to under 100°; standard-wide from 55° to under 75°; normal from 38° to under 55°; short telephoto from 20° to under 38°; telephoto from 8° to under 20°; and super-telephoto below 8°. These names are framing cues, not lens-design standards.

Limitations:

The model assumes rectilinear projection. Fisheye and strongly corrected or distorted lenses do not follow the same edge geometry.
Focus breathing, close-focus extension, digital stabilization, in-camera correction, and video-mode cropping can change effective coverage.
Subject distance is treated as distance to a flat plane. Three-dimensional subjects extend in front of and behind that plane.
Sensor presets are representative active dimensions. Use custom dimensions when the exact capture mode differs.

Worked Example:

A room framed on full frame

A 36 × 24 mm sensor in landscape orientation with a 24 mm lens at 4 m covers about 6 m × 4 m. The horizontal angle is about 73.7°, the vertical angle 53.1°, and the diagonal angle 84.1°. A 5 m target width fits with 1 m of margin, so the fit ratio is 1.20. At the same position, about 28.8 mm is the longest estimated focal length that still fits 5 m; with the 24 mm lens, moving to roughly 3.33 m would produce a 5 m-wide frame.

References:

Understanding Focal Length and Field of View, Edmund Optics.
Calculating Camera Sensor Resolution and Lens Focal Length, National Instruments, updated October 7, 2020.
Guide for the Use of the International System of Units (SI), National Institute of Standards and Technology.