Incident light meter with translucent dome measuring light falling on the subject from 180° angle, not reflected light like a spot meter.
Definition
The Incident Meter is an exposure meter that measures the light falling onto the subject. Unlike spot meters, it does not measure reflected light but the actual amount of light at the shooting location.
Practical Application
Areas of use for the Incident Meter:
- Key Exposure: Measuring the main light source directly at the subject
- Lighting Ratios: Determining the contrast ratio between key and fill light
- Multiple Light Sources: Separate measurement of each light source by switching them on and off
- Color Temperature Control: Matching different light sources before shooting
Technical Details
Construction and Function:
- Frosted dome (Lumisphere) collects light from a 180° angle
- Display in f-stops or lux values
- Typical measuring range f/1.0 to f/90 at ISO 100
- Calibrated to 18% gray reflection
Practical Tips
- Measurement Direction: Lumisphere points towards the camera, not the light source
- Position: Directly at the subject, not at the camera's position
- With mixed lighting: Individual measurements of the light sources
- Measure shadows and highlights separately for contrast ratio
Professional Standards
Advantages over in-camera light meters:
- Independent of subject reflection and image composition
- Precise measurement in extreme contrast ratios
- Reproducible exposure values for series shots
- Basis for consistent lighting setups over multiple shooting days
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