Built-in neutral density filter (1.8 optical density, 6 stops). Cuts light by 98.4 % — lets you shoot shallow depth of field and wide apertures in bright sunlight without external filters mounted to the matte box.
What is ND 1.8 Internal?
ND 1.8 Internal is the strongest internal ND filter in many cinema cameras, especially ARRI. With an optical density of 1.8, it reduces light by 6 stops (98.4%) for extreme brightness situations.
Basic Principle
| Aspect | Description |
|---|---|
| Optical Density | 1.8 |
| Light Reduction | 6 Stops / 98.4% |
| Transmission | 1.56% |
| Special Feature | ARRI Maximum |
ND Scale Context
| ND Value | Stops | Transmission |
|---|---|---|
| 0.9 | 3 | 12.5% |
| 1.2 | 4 | 6.25% |
| 1.5 | 5 | 3.125% |
| 1.8 | 6 | 1.56% |
| 2.1 | 7 | 0.78% |
ARRI ALEXA ND System
| Position | ND Value | Stops |
|---|---|---|
| 1 | Clear | 0 |
| 2 | 0.6 | 2 |
| 3 | 1.2 | 4 |
| 4 | 1.8 | 6 |
When ND 1.8?
| Situation | Description |
|---|---|
| Blinding Sun | Desert, snow, beach |
| Maximum Aperture | T1.3-T2 during the day |
| Extreme Brightness | Midday sun |
| Stylistic Choice | Bokeh in daylight |
Practical Example
| Without ND | With ND 1.8 |
|---|---|
| T22+ @ ISO 800 | T2.8 @ ISO 800 |
| T16 | T2 |
| T11 | T1.4 |
Typical Applications
| Scenario | Advantage |
|---|---|
| Desert Shoot | Open aperture despite sun |
| Beach Scenes | Shallow DOF with reflections |
| Snow | Control in bright conditions |
| High Summer Midday | Creative freedom |
Combination for More
| Internal | + External | Total |
|---|---|---|
| 1.8 | + 0.3 | 2.1 (7 Stops) |
| 1.8 | + 0.6 | 2.4 (8 Stops) |
| 1.8 | + 0.9 | 2.7 (9 Stops) |
Comparison: Cameras
| Camera | Max Internal | Stops |
|---|---|---|
| ARRI ALEXA | ND 1.8 | 6 |
| Sony Venice | ND 2.4 | 8 |
| Canon C500 | 6 Stops | 6 |
| RED Komodo | Optional | — |
IRND Quality
| Aspect | Description |
|---|---|
| IR Blocking | Fully integrated |
| Color Cast | None |
| Sharpness | Unaffected |
| Optics | Camera-optimized |
Workflow Extreme Sun
| Step | Description |
|---|---|
| 1 | Start with ND 1.8 |
| 2 | Select desired aperture |
| 3 | Add external filters if needed |
| 4 | Adjust ISO last |
Limitations
| Factor | Description |
|---|---|
| Maximum | 6 stops on ARRI |
| Extreme Situations | External filters required |
| Not Variable | Fixed level |
ND 1.8 vs. External
| Aspect | ND 1.8 Internal | External Addition |
|---|---|---|
| Change Time | Instant | Filter change |
| Dust | Protected | Risk |
| Vignetting | None | Possible |
| Strength | 6 stops fixed | Arbitrary |
Best Practices
| Practice | Reason |
|---|---|
| Use as Maximum | Then add external |
| Plan Combination | With 0.6 or 0.9 |
| Consistent in Scene | Matching |
| Document | Continuity report |
Today
ND 1.8 Internal represents the maximum internal filtering in ARRI cameras. The 6-stop reduction allows for creative work even under the most extreme lighting conditions. For most outdoor situations, the combination of internal ND 1.8 and, if necessary, external filters is sufficient.
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