ETC Source Four ellipsoidal; the theater-derived standard used on set for gobo projections — window patterns, venetian blinds, foliage breakup — and hard, precisely shaped beam edges.
Definition
The Source Four (often abbreviated as S4) is an ellipsoidal reflector spotlight with interchangeable lens tubes and is referred to as the "industry standard" in film, television, and theater. It is manufactured by ETC (Electronics Theatre Controls).
Construction and Features
Optical System
- Lens Design: Ellipsoidal reflector combination with interchangeable lenses
- Focal Length: Various lenses for different throw distances
- Projection: Sharp, defined light edges with shutter control
- Efficiency: Highly efficient reflector system with low losses
Lens Options
| Lens Type | Throw Distance | Application |
|---|---|---|
| 26° | 7-15m | Medium, standard range |
| 36° | 5-10m | Wider beam |
| 50° | 3-7m | Large area illumination |
| 70° | 2-4m | Very wide beam |
Practical Applications
The Source Four is used for:
- Professional Profile Spots: Sharply defined light with patterns
- Gobo Projection: Structural light patterns (windows, trees, etc.)
- Precision Light Control: Exact light edges and delineations
- Theatrical Effects: Applied in film and television
- Studio Key Lighting: Standard in many film studios
Shutter System
The Source Four has four adjustable shutters:
- Top Shutter: Top edge cut
- Bottom Shutter: Bottom edge cut
- Left Shutter: Left edge cut
- Right Shutter: Right edge cut
This allows for precise light contours without the need for additional barndoors.
Accessories and Modifications
Available with:
- Gobo Rotator: Rotating patterns for dynamic effects
- Iris Diaphragm: Electronic iris for variable size adjustment
- Color Changer: Automatic color change (often with DMX control)
- Diffusion Frames: Holders for diffusion and color gels
Variations
- Source Four Standard: Standard model
- Source Four Jr.: More compact version with lower wattage
- Source Four Par: PAR version without lenses
- Source Four LED: Modern LED version with full color spectrum
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