Neutral Density filter with optical density 1.8, reducing light by six stops (ND64), enabling wide apertures and motion control in extreme bright conditions or slow motion.
Optical Density and Aperture Value
The ND 1.8 filter (also known as ND64) has an optical density of 1.8 and reduces incoming light by six stops. This means the amount of light is reduced to 1/64th.
The ND64 designation system indicates: ND64 means the light is divided by 64. This corresponds to a reduction of 6 stops (6 x halving = 1/64).
Typical Applications
Extreme Light Situations
The ND 1.8 is ideal for harsh midday sun or bright reflections (snow, water, sand). With six stops of reduction, you can work with a wide aperture like f/1.4 or f/2.0 even under the most extreme sunlight.
Slow-Motion Shots
When you need to shoot at 60fps, 120fps, or higher, you often require additional light reduction. The ND 1.8 makes slow motion possible in daylight without needing to use extreme apertures (f/16).
Emotional Close-Ups
The ND 1.8 allows for extremely shallow depth of field even during the day – perfect for emotional close-ups or portrait shots with dramatic background bokeh.
Difference from Variable ND Filters
Variable ND filters can cover the ND 1.8 range but have:
- Color Shifts: At extreme settings (above ND64), noticeable magenta or green color casts appear.
- Cross-Polarization Patterns: X-shaped vignetting at wide angles.
- Moiré Effects: Disruptive interference appears with fine patterns in the scene.
- Loss of Sharpness: More internal glass layers lead to optical losses.
The fixed ND 1.8 is optically superior and color-neutral.
Relation to the 180-Degree Shutter Rule
The ND 1.8 is often necessary when you want to adhere to the 180-degree shutter rule in extreme light with a very wide aperture. Example:
- Extreme midday sun: 100,000+ Lux
- Desired: f/1.4, 1/50 sec (180 degrees at 25p), ISO 200
- ND 1.8 enables exactly this combination
Combined with an ND 1.2, it results in an ND 3.0 (10 stops) – this is the limit for practical filmmaking in extreme daylight.
Practical Use Cases
Scenario 1: Slow Motion in Daylight
- Recording Format: 120fps (2x longer exposure time)
- Light: 50,000 Lux
- Desired: f/4, 180-degree shutter
- ND 1.8 is often the right choice
Scenario 2: Emotional Portraits
- Midday outdoor shots in bright sun
- Desire: f/1.4 for minimal depth of field
- ND 1.8 makes this possible
Scenario 3: Water/Snow Shots
- Strong reflections double the brightness
- Desired: f/2.0 with motion blur
- ND 1.8 is the solution
Specifications
- Optical Density: 1.8
- Light Loss: 6 stops
- Multiplier: ND64
- Typical Transmission Rate: 1.56%
- Usage Range: Very bright to extreme daylight
- Standard Format: Matte Box 4x4", Screw-On 77mm-95mm
Combinations with Other Filters
- ND 1.8 + ND 0.3 = ND 2.1 (7 stops)
- ND 1.8 + ND 0.6 = ND 2.4 (8 stops)
- ND 1.8 + ND 1.2 = ND 3.0 (10 stops - extreme situations)
Practical Application Examples
- Slow-Motion Shots: 60fps, 120fps in daylight
- Snow Reflections: Polarized snow in bright sun
- Water Shots: Lakes, seas with extreme brightness
- Emotional Portraits: Minimal depth of field even at midday
- Vertical Format Cameras: Alexa, RED with large sensors