LensCalc

Field of View Calculator

How wide does this lens see?

Focal Length (mm)

Sensor Width (mm)

Sensor Height (mm)

Horizontal FOV

39.6°

Vertical FOV: 27°
Diagonal FOV: 46.8°

What you entered

Focal Length (mm): 50Sensor Width (mm): 36Sensor Height (mm): 24

1
Sensor diagonal
sqrt(36^2 + 24^2)= 43.2666 mm
2
Horizontal FOV
2 x arctan(36 / (2 x 50))= 39.5978deg
3
Vertical FOV
2 x arctan(24 / (2 x 50))= 26.9915deg
4
Diagonal FOV
2 x arctan(43.2666 / (2 x 50))= 46.793deg

Result

Horizontal FOV: 39.6°

Field of view by focal length on full frame

Angle of view depends on focal length and sensor dimensions. Rows use a 36 x 24 mm full-frame sensor.

Focal length	Horizontal	Vertical	Diagonal	Typical use
14 mm	104.25 deg	81.20 deg	114.18 deg	Ultra-wide, architecture
24 mm	73.74 deg	53.13 deg	84.06 deg	Wide landscape
35 mm	54.43 deg	37.85 deg	63.44 deg	Documentary, street
50 mm	39.60 deg	26.99 deg	46.79 deg	Normal, close to human view
85 mm	23.91 deg	16.07 deg	28.56 deg	Portraits
135 mm	15.19 deg	10.16 deg	18.21 deg	Tight portraits
200 mm	10.29 deg	6.87 deg	12.35 deg	Sports, wildlife
400 mm	5.15 deg	3.44 deg	6.19 deg	Distant wildlife

Doubling the focal length roughly halves the angle of view, but not exactly, because the relationship is a tangent rather than a straight ratio. The effect is most obvious at the wide end.

FOV = 2 × arctan(sensor ÷ 2×focal length)

The field of view is a pure trigonometry calculation — the sensor size is the base and the focal length is the distance, so arctan gives the half-angle, which you double for the full viewing angle.

Why diagonal FOV is the standard spec

Lens manufacturers list diagonal FOV because it's the largest angle and looks most impressive on spec sheets — but horizontal FOV is what determines how much of a scene you actually capture in a landscape-oriented photo.

Frequently asked questions

What's the field of view of a 24mm lens on full frame?

A 24mm lens on a 36×24mm sensor gives about 84 degrees diagonal, 74 degrees horizontal, and 53 degrees vertical. That's a classic wide-angle perspective for landscape and architecture.

How is field of view related to depth of field?

They're both affected by focal length but measure different things. FOV is the angular extent of the scene captured (wider lens = wider FOV). DOF is how much of the scene is in focus front-to-back. A wider FOV lens also tends to have deeper DOF at the same aperture.

Why does my phone's 'ultrawide' lens distort the edges?

Ultrawide lenses (120+ degrees FOV) use rectilinear projection that stretches objects at the frame edges. Barrel distortion is also common. The wider the FOV, the more extreme this stretching — fisheye lenses solve it differently by curving straight lines.

Does crop factor change the actual field of view?

Yes. A smaller sensor captures a narrower portion of the image circle, effectively reducing the FOV. A 50mm lens on a 1.5x crop sensor has the same FOV as a 75mm on full frame — about 32 degrees diagonal instead of 47 degrees.