Source Four Focal Length, Pattern Size and Image Diameters

[Go Back]

Source Four Focal Length, Pattern Size and Image Diameters

Question
What Size Patterns Do Source Fours Use and What Are The Image Diameters and Focal Lengths?

Answer
Source Four uses "A" and/or "B" size patterns and Source Four jr uses "M" size patterns.
Type Outer Diameter Max Image Diameter
A 3.93"/100mm 2.95"/75.0mm
B 3.38"/86mm 2.53"/64.5mm
M 2.57"/65.5mm 1.94"/49.5mm

The gate size in a Source Four is 3.12"/79.24mm.
The gate size in a Source Four jr is 2.15"/54.61mm.

Focal Length Source Four:
90 degree
2.13"/54.1mm
70 degree
2.67"/67.82mm
50 degree
3.3"/83.82mm
36 degree
4.8"/121.92mm
26 degree
6.8"/172.72mm
19 degree
9.3"/236.22mm
14 degree
11.05"/280.67mm
10 degree
17.8"/452.12mm
5 degree
25.5"/647.70mm

Focal Length Source Four jr:
26 degree 4.66"/118.3mm
36 degree 3.27"/83.18mm
50 degree 2.33"/59.18mm

Fixture Actual Field Angle (per 7/2003 testing) Lens Focal Length
S4 15-30 16.2° minimum 278mm
31.3° max 141mm
S4 25-50 26.9° minimum 166mm
49.0° max 87mm