The field of view tells you how much of a scene your lens captures — essential for choosing a focal length before a shoot, planning where to stand, or matching lenses across camera formats. This calculator returns the angle of view in three directions and the real-world frame size at any distance.
How it works
Angle of view depends on the focal length and the sensor dimension in that direction:
angle = 2 × arctan( sensor dimension ÷ (2 × focal length) )
The horizontal angle uses the sensor width, the vertical uses the height, and the
diagonal uses √(width² + height²). Because a larger sensor captures more of the
lens’s image circle, the same focal length is wider on full frame than on a
cropped sensor — that is the origin of the crop factor.
To find real-world coverage at a subject distance d, the tool projects the
angle outward:
frame width = 2 × d × tan(horizontal angle ÷ 2)
Worked example
A 35 mm lens on full frame (36 × 24 mm) gives:
horizontal = 2 × arctan(36 ÷ 70) ≈ 54.4°, vertical ≈ 37.8°, diagonal ≈ 63.4°
At 3 m the frame covers about 2 × 3 × tan(27.2°) ≈ 3.08 m wide — roughly enough
for a full-body portrait with a little room to spare.
Tips
Use the horizontal angle for video and landscape framing, the vertical for tall subjects, and the diagonal when comparing against the lens maker’s stated figure. To match a look across cameras, multiply focal length by the crop factor: a 35 mm on full frame frames like a 23 mm on APS-C or an 18 mm on Micro Four Thirds.
Sensor formats and their crop factors
The same focal length produces a different field of view on different sensor sizes. The crop factor is the ratio of a sensor’s diagonal to a full-frame sensor’s diagonal (43.3 mm):
| Format | Approximate sensor size | Crop factor | 50mm equiv. lens |
|---|---|---|---|
| Full frame (35mm) | 36 × 24 mm | 1.0× | 50mm |
| APS-C (Canon) | 22.3 × 14.9 mm | ~1.6× | ~31mm |
| APS-C (Nikon/Sony) | 23.5 × 15.6 mm | ~1.5× | ~33mm |
| Micro Four Thirds | 17.3 × 13 mm | 2.0× | 25mm |
| 1-inch (compact/video) | 13.2 × 8.8 mm | ~2.7× | ~18mm |
| Medium format (Fuji GFX) | 43.8 × 32.9 mm | ~0.79× | ~63mm |
Medium format sensors are actually larger than full frame, giving a slightly wider field of view with the same focal length (inverse crop factor below 1.0).
Real-world coverage at different distances
Knowing the angle of view tells you something abstract; knowing how many metres of scene you capture at a given distance tells you something practical. For portrait photography, a 20-degree horizontal angle at 5 m captures 2 × 5 × tan(10°) ≈ 1.76 m wide — enough for a tight headshot. For architecture, a 70-degree horizontal angle at 10 m covers 2 × 10 × tan(35°) ≈ 14 m — enough for a wide facade shot.
Enter your subject distance and the coverage section of this tool does the trigonometry automatically, in both metres and feet.
Common shooting situations and what angle to aim for
- Environmental portrait (person in a room): 50–65° horizontal, equivalent to a 28–35 mm full-frame lens, to show context without distorting the subject
- Head-and-shoulders portrait: 20–30° horizontal, equivalent to 75–100 mm, for natural facial proportions
- Group of 6 people at 4 m: roughly 70° horizontal or wider to capture the group across the frame
- Landscape with wide foreground interest: 80–100° horizontal, typically a 16–20 mm lens on full frame
- Wildlife at 30 m: often 8° horizontal or narrower, requiring 200 mm or longer on full frame
Use the coverage output in this tool to work backwards: set the scene width you want to cover, adjust the distance you can realistically stand, and solve for the focal length that delivers that angle of view on your sensor.