Calculating Beam Diameters - High End Systems studio spot User Manual

Calculating Beam Diameters

Use the following table to calculate the beam diameter with each type of
lens. Calculations can be used for feet or meters.
C-6 Studio Spot User's Manual
Table C.3: Calculating Beam Diameters
Distance From 13° Lens
Fixture Diameter
5 1.1
10 2.3
15 3.4
20 4.5
25 5.7
30 6.8
35
40 9.1
45 10.3
50 11.4
55 12.5
60 13.7
65 14.8
70
75 17.1
80 18.2
85 19.4
90 20.5
95 21.6
100 22.8
18° Lens
Diameter
1.6
3.2
4.8
6.3
7.9
9.5
8 11.1
12.7
14.3
15.8
17.4
19
20.6
16 22.2
23.8
25.3
26.9
28.5
30.1
31.7
30° Lens
Diameter
2.7
5.4
8
10.7
13.4
16.1
18.8
21.4
24.1
26.8
29.5
32.2
34.8
37.5
40.2
42.9
45.6
48.2
50.9
53.6