Field of View Calculator
Calculates the horizontal angle of view for any lens and sensor combination, showing how wide or narrow a scene your camera captures. Use it when choosing a lens focal length for a specific shot or comparing cameras with different sensor sizes.
About this calculator
Field of view (FoV) is the angular extent of the scene captured by a lens-sensor combination, measured in degrees. The horizontal FoV is calculated as FoV = 2 × arctan(s / (2 × f)), where s is the sensor width in mm and f is the focal length in mm. A wider sensor or shorter focal length produces a larger angle of view, capturing more of the scene. On a full-frame 35 mm sensor (s = 36 mm), a 50 mm lens gives roughly a 39.6° FoV, close to normal human vision. On an APS-C sensor (s ≈ 23.5 mm), the same 50 mm lens yields a narrower ≈ 26.5° FoV, equivalent to a 75 mm lens on full frame — often called the crop factor effect.
How to use
Suppose you use a 35 mm lens on a full-frame sensor (sensor width = 36 mm). Apply the formula: FoV = 2 × arctan(36 / (2 × 35)) = 2 × arctan(36 / 70) = 2 × arctan(0.5143). arctan(0.5143) ≈ 27.2°, so FoV = 2 × 27.2° ≈ 54.4°. This wide angle of view makes a 35 mm lens popular for street and documentary photography. Try it with a 50 mm lens on the same sensor: FoV = 2 × arctan(36/100) ≈ 39.6°, noticeably narrower.
Frequently asked questions
How does focal length affect the field of view of a camera lens?
Focal length and field of view have an inverse relationship: shorter focal lengths produce wider angles of view, while longer focal lengths narrow the field of view and magnify distant subjects. For a fixed sensor size, halving the focal length roughly doubles the tangent of the half-angle, so wide-angle lenses like 16–24 mm capture expansive scenes while telephoto lenses like 200–400 mm isolate small portions of a scene. This is why zoom lenses let photographers frame a shot from a single position by simply adjusting focal length.
What is the crop factor and how does it change the effective field of view?
Crop factor is the ratio of a full-frame sensor's diagonal (43.3 mm) to the diagonal of a smaller sensor. An APS-C sensor with a crop factor of 1.5× means that a given focal length produces the same FoV as a focal length 1.5 times longer would on a full-frame body. So a 35 mm lens on an APS-C camera behaves like a 52.5 mm 'equivalent' on full frame. This is important when comparing lenses across camera systems or when trying to replicate a specific angle of view.
Why do photographers calculate field of view when planning a shoot?
Knowing the FoV in advance allows photographers to determine how far they need to stand from a subject to fill the frame, or which lens to pack when access or movement is limited. For architecture photography, a too-narrow FoV may cut off the building, while for wildlife a too-wide FoV may make the subject appear tiny. Pre-calculating FoV is also essential when using cameras on drones, telescopes, or rigs where changing the lens mid-shoot is impractical, and when stitching panoramas where knowing the angular coverage of each frame is critical.