Introduction
You've locked a location with a narrow hallway, and the director wants a wide establishing shot that captures both walls and the ceiling. You know a 14mm will probably work on your RED V-RAPTOR, but will it actually cover enough of the room at the planned camera position 8 feet from the far wall? You need horizontal angle, not guesswork.
The field of view calculator gives you the exact angular coverage and frame dimensions for any combination of focal length and sensor size. Enter two numbers. Get the answer in degrees and in real-world frame width at your subject distance.
This is the tool you use before you rent lenses, not after you discover on set that your widest prime still can't fit the shot.
What This Tool Calculates
The calculator accepts three inputs: sensor width in millimeters, focal length in millimeters, and subject distance in meters or feet.
It returns horizontal field of view in degrees, vertical field of view in degrees (based on the sensor's aspect ratio), diagonal field of view, and the physical width and height of the frame at the specified subject distance. These numbers let you plan framing precisely during pre-production.
The Formula and How It Works
The field of view is calculated using the standard rectilinear lens formula: FoV = 2 times arctan(d / (2 times f)), where d is the relevant sensor dimension (width, height, or diagonal) in millimeters and f is the focal length in millimeters.
For the horizontal FoV on a Full Frame sensor (36mm wide) with a 24mm lens: FoV = 2 times arctan(36 / (2 times 24)) = 2 times arctan(0.75) = 2 times 36.87 degrees = 73.74 degrees.
The physical frame width at a given distance uses simple trigonometry: Frame Width = 2 times distance times tan(FoV / 2). At 5 meters distance with a 73.74-degree horizontal FoV: Frame Width = 2 times 5 times tan(36.87) = 2 times 5 times 0.75 = 7.5 meters.
This formula assumes rectilinear (non-fisheye) lenses. Fisheye lenses use an equidistant or equisolid projection that produces wider angles than this formula predicts. For cinema work, virtually all primes and zooms are rectilinear.
Real-World Examples
Location Scout for Hallway Tracking Shot
A production designer needed to confirm that a Steadicam operator could capture both walls of a 3.2-meter-wide hospital hallway. Using an 18mm lens on the ARRI ALEXA 35 (Super 35 sensor, 24.89mm width), the calculator returned a horizontal FoV of 69.1 degrees and a frame width of 3.67 meters at a distance of 2 meters. The hallway fit comfortably, and the Steadicam operator had 23cm of margin on each side for slight lateral movement.
Drone Shot Coverage Planning
An aerial cinematographer flying a DJI Inspire 3 (Full Frame sensor) at 50 meters altitude with the 24mm DL lens needed to know how much ground the frame covered. The calculator showed a horizontal frame width of 75 meters at 50 meters distance. The client's event space measured 60 meters across, confirming the 24mm lens would capture the entire venue with room to spare for stabilization crop.
Matching Lens Across Two Camera Bodies
A multi-camera interview required matching frame sizes between an ALEXA Mini LF (Full Frame) and a Sony FX6 (Super 35). On the ALEXA Mini LF, a 50mm lens produced a horizontal FoV of 39.6 degrees. To match that angle on the FX6 (23.5mm sensor width), the calculator showed a 35mm lens produced 37.1 degrees and a 40mm produced 32.7 degrees. The crew selected the 35mm and adjusted camera position slightly to match framing.
Common Focal Lengths and Horizontal FoV by Sensor
| Focal Length | Full Frame (36mm) | Super 35 (24.89mm) | Micro 4/3 (17.3mm) |
|---|---|---|---|
| 14mm | 104.3 deg | 83.2 deg | 63.7 deg |
| 24mm | 73.7 deg | 54.8 deg | 39.7 deg |
| 35mm | 54.4 deg | 39.2 deg | 27.8 deg |
| 50mm | 39.6 deg | 27.9 deg | 19.6 deg |
| 85mm | 23.9 deg | 16.7 deg | 11.6 deg |
| 135mm | 15.2 deg | 10.5 deg | 7.3 deg |
Pro Tips and Common Mistakes
Pro Tips
- Print a FoV chart for your camera and lens kit. Tape it inside your lens case or camera cart. On a fast-moving set, looking up the frame width at a given distance takes 3 seconds instead of running the math.
- When comparing lenses across sensor sizes, compare the horizontal angle, not the focal length. A 35mm on Super 35 and a 50mm on Full Frame produce nearly identical framing.
- If you're shooting for a vertical delivery (9:16), swap the sensor dimensions. Enter the sensor height as the width input, because your vertical FoV becomes the critical framing dimension.
- Ultra-wide lenses below 16mm on Full Frame begin to show noticeable barrel distortion at the frame edges. The FoV formula remains accurate at center, but practical framing near the edges will appear stretched.
Common Mistakes
- Confusing diagonal FoV with horizontal FoV. Lens manufacturers often advertise the diagonal number because it's larger. The horizontal FoV is what determines how much width you capture, and it's always smaller than the diagonal.
- Forgetting crop modes. Many cameras offer a Super 35 crop mode on a Full Frame sensor. If the camera is set to crop mode, you must use the cropped sensor width, not the full sensor width.
- Not accounting for stabilization crop. In-body or electronic stabilization trims the frame edges, reducing effective FoV by roughly 5 to 10 percent depending on the system.
Frequently Asked Questions
How do I calculate field of view for a zoom lens?
Enter the focal length at each end of the zoom range to get the widest and tightest FoV. Zoom lenses are rectilinear at all focal lengths, so the formula works at any position in the zoom range. Run the calculation at the focal lengths you actually plan to use, not just the extremes.
What sensor size does the ARRI ALEXA 35 use?
The ALEXA 35 uses a Super 35 sensor measuring 27.99mm by 19.22mm. Note this is slightly wider than the traditional Super 35 standard of 24.89mm, so always check your specific camera's sensor dimensions rather than relying on the generic category name.
Can I use this for VR or 360-degree video?
No. VR cameras use fisheye lenses with non-rectilinear projections. This calculator assumes a rectilinear lens where straight lines in the scene remain straight in the image. Fisheye FoV requires a different formula based on the projection type (equidistant, equisolid, or stereographic).
Why does my measured frame width differ from the calculated value?
The most common reason is that your camera is in a crop mode you didn't account for. Also check whether your lens has breathing, which slightly changes the effective focal length as you focus closer. Cinema lenses are designed to minimize breathing, but photo lenses can shift noticeably.
Start Calculating
Knowing your exact frame coverage before you show up to set eliminates surprises and speeds up lens selection during pre-production. Whether you're scouting locations, planning drone shots, or matching cameras in a multi-cam setup, the field of view calculator is the starting point.
Run your planned setups through the calculator above and save the results to your shot list. What lens and sensor combination do you find yourself defaulting to for wide establishing shots?
