Camera distance & field-of-view calculator
Choose a camera and the distance to your subject to see how wide the picture covers.
Calculated from each model's horizontal field of view (width = 2 × distance × tan(angle ÷ 2)), height at 16:9. The diagram is a top view: light green is the wide shot, dark green the close-up, and the dots show roughly how many people fit across at that distance (about 1.2 m each). Actual coverage varies slightly with mounting height and angle.
Distance and coverage table
In metres. Wide is fully zoomed out; close-up is fully zoomed in.
| Distance (m) | 2 | 3 | 5 | 10 | 15 | 20 |
|---|---|---|---|---|---|---|
| 20 × optical zoom (P20i, TX20i) close-up | N/A | 0.2 | 0.3 | 0.6 | 0.9 | 1.2 |
| 20 × optical zoom (P20i, TX20i) wide | N/A | 3.5 | 5.9 | 11.7 | 17.6 | 23.4 |
| 12 × optical zoom (S12+, P12i) close-up | N/A | 0.4 | 0.6 | 1.2 | 1.8 | 2.4 |
| 12 × optical zoom (S12+, P12i) wide | N/A | 4.4 | 7.3 | 14.7 | 22 | 29.3 |
| A01 wide | 6.5 | 7.8 | 13 | N/A | N/A | N/A |
How to use this calculator
- Choose a model: the list shows the cameras that have optical field-of-view data.
- Drag “Distance to subject” between 2 and 30 metres.
- Read the numbers: “Wide” is the width you can capture at that distance with the lens fully zoomed out; “Close-up” is the width with the lens fully zoomed in; the height is worked out at 16:9.
- Read the diagram: light green is the wide shot, dark green the close-up, and the dots on the black line show roughly how many people fit across at that distance (about 1.2 m each).
The calculation uses the horizontal field of view in each model’s specification: width = 2 × distance × tan(angle ÷ 2). Actual coverage varies a little with mounting height and angle.
What do “wide” and “close-up” mean?
The optical zoom of a PTZ camera can zoom out or in. “Wide” is the lens fully zoomed out, where the camera sees the largest area; “Close-up” is the lens fully zoomed in (the telephoto end), where it sees the smallest area but the people in the picture are largest. At the same distance, these two numbers are the range the camera can cover: wide decides whether everyone fits in, and close-up decides whether people far away can be brought close enough to see clearly.
A worked example from the table
Say the camera is 10 metres from the front. With the 12x S12+ or P12i, the wide shot is 14.7 m across and the close-up is 1.2 m across; with the 20x P20i or TX20i, the wide shot is 11.7 m across and the close-up only 0.6 m. In other words, fully zoomed in, a 20x lens shows a picture only 0.6 m wide, enough for a close-up of the speaker’s face; but its wide shot is narrower than the 12x lens, because the higher the zoom ratio, the narrower the area the lens can see.
How to use the table to choose a camera
- Small space, 2 to 5 metres: the A01 is a fixed ultra-wide lens; its wide shot is 6.5 m across at 2 m, 7.8 m at 3 m and 13 m at 5 m, enough to fit everyone in one picture.
- Medium distance (5 to 10 metres): the 12x S12+ gives a wide shot 7.3 m across at 5 m and 14.7 m at 10 m, and can zoom in for a close-up.
- Long distance (over 10 metres): the 20x P20i and TX20i give a close-up 0.6 m across at 10 m, 0.9 m at 15 m and 1.2 m at 20 m, so a speaker far away can still be framed close.
A simple rule of thumb: 12x suits a space of about 12 metres, and 20x about 20 metres. In practice, decide by the depth of the room, the seating and the mounting height, and test with sample units in the room if needed.
Frequently asked questions
Why is the 20x wide shot narrower than the 12x one at the same distance?
Because the wide end of the 20x models has a narrower field of view (about 60° for the P20i and TX20i, against 72.5° for the S12+). The higher the zoom ratio, the further the lens reaches, but the narrower the area it sees, so a higher ratio is not always better.
How is the height worked out?
The picture is 16:9, so height = width × 9 ÷ 16. For example, a picture 14.7 m wide is about 8.3 m high.
Which camera suits a huddle room?
For a huddle room, a small meeting room with the camera about 2 to 5 metres from the people, look at the A01: at 3 m its wide shot is 7.8 m across, so one fixed picture fits a whole table. If people sit further away and you need to zoom in, consider a PTZ camera with optical zoom.