Field of View Calculator

Field of View (FOV) Calculator

Full Frame (35mm) – 36 x 24 mm APS-C (Nikon/Sony/Fuji) – 23.5 x 15.6 mm APS-C (Canon) – 22.2 x 14.8 mm Micro Four Thirds – 17.3 x 13 mm 1-inch Sensor – 13.2 x 8.8 mm Custom Dimensions…

Calculation Results

Horizontal Angle: °

Vertical Angle: °

Diagonal Angle: °

Width at Distance: m

Height at Distance: m

Diagonal at Distance: m

Understanding Field of View in Photography

Field of View (FOV) defines the extent of the observable world that is seen through the camera lens at any given moment. It is determined by the relationship between the focal length of the lens and the physical size of the camera sensor.

Key Factors Affecting FOV:

  • Focal Length: A shorter focal length (e.g., 14mm) provides a wide field of view, while a longer focal length (e.g., 200mm) results in a narrow, zoomed-in field of view.
  • Sensor Size: Larger sensors (like Full Frame) capture more of the image projected by the lens compared to smaller sensors (like APS-C or Micro Four Thirds), which effectively "crop" the image.
  • Subject Distance: While the angular FOV remains constant regardless of distance, the linear FOV (the actual width and height in meters) increases as you move further from the subject.

The Math Behind the Calculation

The angular field of view ($\alpha$) is calculated using the formula:

α = 2 * arctan(h / (2 * f))

Where h is the sensor dimension (width, height, or diagonal) and f is the focal length. To find the linear FOV at a specific distance, we use basic trigonometry to project that angle over the distance D.

Example Calculation

If you are using a 50mm lens on a Full Frame sensor (36mm width) and focusing on an object 5 meters away:

  • Horizontal Angle: 2 * arctan(36 / (2 * 50)) ≈ 39.6°
  • Horizontal Width: The camera will capture a scene roughly 3.6 meters wide at that 5-meter distance.
function updateSensorDimensions() { var preset = document.getElementById("sensorPreset").value; var customDiv = document.getElementById("customSensorFields"); var widthInput = document.getElementById("sensorWidth"); var heightInput = document.getElementById("sensorHeight"); if (preset === "custom") { customDiv.style.display = "grid"; } else { customDiv.style.display = "none"; var dims = preset.split(","); widthInput.value = dims[0]; heightInput.value = dims[1]; } } function calculateFOV() { var f = parseFloat(document.getElementById("focalLength").value); var d = parseFloat(document.getElementById("subjectDistance").value); var w = parseFloat(document.getElementById("sensorWidth").value); var h = parseFloat(document.getElementById("sensorHeight").value); if (isNaN(f) || isNaN(d) || isNaN(w) || isNaN(h) || f <= 0 || d <= 0) { alert("Please enter valid positive numbers for all fields."); return; } // Calculate diagonal sensor size var diag = Math.sqrt(Math.pow(w, 2) + Math.pow(h, 2)); // Calculate Angular FOV in Radians // Formula: Angle = 2 * arctan(sensor_dimension / (2 * focal_length)) var radH = 2 * Math.atan(w / (2 * f)); var radV = 2 * Math.atan(h / (2 * f)); var radD = 2 * Math.atan(diag / (2 * f)); // Convert to Degrees var degH = radH * (180 / Math.PI); var degV = radV * (180 / Math.PI); var degD = radD * (180 / Math.PI); // Calculate Linear FOV (Width/Height at distance) // Formula: Linear = 2 * distance * tan(angle / 2) // Which simplifies back to: Linear = (sensor_dimension * distance) / focal_length // Note: Distance is in meters, sensor/focal in mm, so multiply by 1000 or keep units consistent. // Result in meters: (mm * m) / mm = meters. var linH = (w * d) / f; var linV = (h * d) / f; var linD = (diag * d) / f; // Display results document.getElementById("resHorizAngle").innerText = degH.toFixed(2); document.getElementById("resVertAngle").innerText = degV.toFixed(2); document.getElementById("resDiagAngle").innerText = degD.toFixed(2); document.getElementById("resHorizLinear").innerText = linH.toFixed(2); document.getElementById("resVertLinear").innerText = linV.toFixed(2); document.getElementById("resDiagLinear").innerText = linD.toFixed(2); document.getElementById("fovResults").style.display = "block"; }

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