How do I calculate the Nexus 5 camera’s field of view correctly?
Asked 9/6/2014
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2 answers
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I’m trying to calculate the field of view of the Nexus 5 rear camera. The published specs list:
- aperture: f/2.4
- focal length (35mm equivalent): 30.4 mm
- sensor size: 1/3.2"
I used the formula FOV = 2 * atan(W / (2f)), with a sensor width of about 4.54 mm for a 1/3.2" sensor and f = 30.4 mm, which gave me a very narrow angle. But in practice, at 1 meter away, the camera sees much more of the subject than that calculation suggests.
What am I doing wrong? Should I be using the actual focal length instead of the 35mm-equivalent value, and what is the approximate horizontal/vertical field of view for the Nexus 5?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
11y ago
2 Answers
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The actual focal length is 4mm. The 35mm equivalent tells you what focal length you'd need to use with a 35mm film/sensor to achieve the same result, but it doesn't have much optical sense.
Assuming the sensor width is 4.54mm:
FOV = 2*atan(.5*4.54mm/4mm)
FOV ~ 1.03235913 rad
FOV ~ 59.1498211 deg
That is roughly 40% of a human's field of view.
Originally by user11943. Source · Licensed CC BY-SA 4.0
user11943
11y ago
0
Generated from our catalog & community — verify before relying on it.
Your mistake is using the 35mm-equivalent focal length in the FOV formula. For field of view, you must use the lens’s actual focal length, not the equivalent value.
For the Nexus 5, the actual focal length is about 4.0 mm (reported around 3.97 mm), while the sensor is about 4.6 × 3.5 mm. Using:
FOV = 2 × atan(sensor dimension / (2 × focal length))
gives approximately:
- horizontal FOV: about 60°
- vertical FOV: about 48°
Using a 4.54 mm sensor width and 4.0 mm focal length gives roughly 59° horizontally, which matches real-world behavior much better.
The 30.4 mm figure only means “this gives the same angle of view as a 30.4 mm lens on a 35mm/full-frame camera.” It is not the physical focal length of the phone lens, so plugging it directly into the formula makes the angle seem far too narrow.
At 1 m distance, a ~60° horizontal FOV would cover roughly: 2 × 1 × tan(30°) ≈ 1.15 m
which is much closer to what you actually see.
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