Neutral Density filter reducing light by 3 stops. Standard choice for exteriors when ambient exposure runs too hot.
Definition
The ND.9 is a neutral density filter providing 3 stops of light reduction (factor 8). It reduces light by 87.5% without color shift.
Practical Application
Use for overexposure and creative control:
- Daylight Reduction: Wide apertures in bright sunlight
- Motion Blur: Longer shutter speeds in daylight
- Depth of Field Control: Large apertures without overexposure
- Light Balancing: Equalizing different light intensities
Technical Details
Specifications for film use:
- Optical Density: 0.9
- Light Transmission: 12.5%
- Available Formats: Round filters, matte box inserts, sheet filters
- Materials: Optical glass or polyester film
Practical Tips
- Perform exposure measurement after attaching the filter
- Check for vignetting when stacking multiple ND filters
- Clean only with specialized optical cleaners
- Protect from scratches with appropriate storage
Professional Standards
Quality features for film productions:
- Color neutrality across the entire spectrum
- Uniform density without spots or streaks
- UV and IR blocking for high-quality filters
- Anti-reflective coatings to minimize reflections
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