How to use the field of view calculator
- Enter the focal length printed on the lens, in millimeters.
- Choose your sensor size, or choose to enter your own width and height.
- Optionally enter the distance to the subject to see how large an area fits in the frame.
- Read the horizontal, vertical and diagonal angle of view, the crop factor and the full frame equivalent focal length.
Formula
angle of view = 2 x atan(sensor size / (2 x focal length))
diagonal = square root of (width^2 + height^2)
crop factor = 43.2666 / sensor diagonal
equivalent focal length = focal length x crop factor
scene width = 2 x distance x tan(horizontal angle / 2)
The diagonal of a full frame sensor of 36 by 24 mm is 43.2666 mm. The angle assumes the lens is focused at infinity.
A 35 mm lens
On a full frame sensor the horizontal angle is 2 x atan(36 / 70) = 54.4 degrees, the vertical 37.8 and the diagonal 63.4 degrees. At 10 meters the frame is 10.29 meters wide and 6.86 meters high.
A 50 mm lens on a sensor of 23.5 by 15.6 mm has a diagonal angle of 31.5 degrees, a crop factor of 1.534 and an equivalent focal length of 76.7 mm. A 25 mm lens on a Micro Four Thirds sensor of 17.3 by 13 mm has a crop factor of 1.999 and an equivalent focal length of 50.0 mm.
Why equivalent focal length is useful
Lenses of the same focal length show different amounts of the scene on different sensors. Multiplying by the crop factor gives the focal length that would show the same view on a full frame sensor, so you can compare lenses across cameras. It does not change the depth of field or low light performance, only the angle of view.
Why sensor sizes are approximate
Makers state sensor sizes slightly differently, so two cameras of the same type can differ by a few tenths of a millimeter. Choose Enter my own size and type the width and height from your camera specifications if you want exact numbers.
Focusing close, lens breathing and in-camera cropping make the real angle narrower than the one shown here.
Related photography tools
Use the angle with the 500 Rule Calculator for star photos, plan long exposures with the ND Filter Exposure Calculator, plan a series with the Timelapse Calculator, and solve other angles with the Triangle Calculator.
Assumptions and limits
- The lens is focused at infinity and has no distortion.
- Sensor widths and heights are approximate unless you enter your own.
- Distance to the subject is measured from the lens to a flat scene.
- Teleconverters, adapters and in-camera crops are not modeled.
Frequently asked questions
What is the field of view of a 35 mm lens?
On a full frame sensor, it is 54.4 degrees wide, 37.8 degrees high and 63.4 degrees on the diagonal. On a smaller sensor the angle is narrower.
What is a crop factor?
It is the diagonal of a full frame sensor, 43.2666 mm, divided by the diagonal of your sensor. A sensor of 23.5 by 15.6 mm has a crop factor of about 1.53.
How wide an area fits in the frame at a distance?
Multiply twice the distance by the tangent of half the angle. A 35 mm lens on full frame covers 10.29 meters across at 10 meters.
Does a crop sensor make the lens zoom in?
It narrows the view, which looks like zooming in, but the lens itself is unchanged. The equivalent focal length tells you what full frame lens gives the same view.