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Electronic Theatre Controls Inc

Source Four Pattern Sizes, Image Diameters and Focal Lengths

The Source Four uses "A" and/or "B" size patterns and Revolution and Source Four Jr uses "M" size patterns.

Type Outer Diameter Max Image Diameter
A     3.93"/100mm 2.95"/75.0mm
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:
50 degree = 3.3"/83.82mm
36 degree = 4.8"/121.92mm
26 degree = 6.8"/172.72mm
19 degree = 9.3"/236.22mm
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
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