A rotating wheel of neutral density filters built into a cinema camera body behind the lens mount – allows quick, precise exposure control without changing external filters, maintaining optical path integrity while providing multiple ND strengths accessible via a dial or electronic control.
What is an Internal ND Wheel?
An Internal ND Wheel is a filter wheel built into the camera with multiple neutral density filters. It sits behind the lens mount in the light path and allows for quick exposure adjustment without changing external filters.
Basic Principle
| Aspect | Description |
|---|---|
| Position | Behind Lens Mount |
| Function | Reduce light |
| Access | Wheel or electronic |
| Advantage | Fast, consistent |
Typical Configuration
| Filter | Reduction |
|---|---|
| Clear | No ND |
| ND 0.6 | 2 Stops |
| ND 1.2 | 4 Stops |
| ND 1.8 | 6 Stops |
Advanced Options
| Filter | Reduction |
|---|---|
| ND 2.1 | 7 Stops |
| ND 2.4 | 8 Stops |
| Combined | More possible |
Cameras with Internal ND
| Manufacturer | Models |
|---|---|
| ARRI | Alexa series |
| Sony | Venice, FX9 |
| Canon | C500 II, C700 |
| RED | With module |
ARRI Alexa ND
| Option | Description |
|---|---|
| Standard | 0.6, 1.2, 1.8 |
| Extended | Up to 2.4 |
| Motorized | FSND (Full Spectrum) |
| Control | Wheel on body |
Sony Venice ND
| Feature | Description |
|---|---|
| 8 Stops | From clear to ND 2.4 |
| Electronic | Via menu/wheel |
| Smooth | Seamless transitions |
| Combinable | With external ND |
Advantages
| Advantage | Description |
|---|---|
| Speed | Instant switching |
| Consistency | Always same quality |
| Protection | No external optics |
| Workflow | Simplified |
Optical Quality
| Aspect | Rating |
|---|---|
| Color Neutrality | Very high |
| IR Behavior | Mostly corrected |
| Sharpness | No loss |
| Reflections | Minimized |
IR Issues
| Aspect | Handling |
|---|---|
| Standard ND | Can pass IR |
| FSND | Full Spectrum, IR-Cut |
| Hot Mirror | Additionally built-in |
| Color Fidelity | Better with FSND |
Full Spectrum ND (FSND)
| Feature | Description |
|---|---|
| IR Filtration | Integrated |
| Color Neutral | Across all strengths |
| ARRI | Standard on newer models |
| Advantage | No IR color shift |
Workflow
| Situation | Application |
|---|---|
| Bright outdoors | Engage ND |
| Indoors | Clear or low ND |
| Transition | Switch quickly |
| Effect | Shallow DoF in sun |
ND vs. Iris
| Method | Result |
|---|---|
| ND | DoF remains the same |
| Iris | DoF changes |
| Combination | Flexibility |
| Creative | Choice depending on look |
ND vs. Shutter
| Method | Result |
|---|---|
| ND | Motion blur remains |
| Shutter | Motion blur changes |
| Standard | Maintain 180° shutter |
| ND preferred | For consistent look |
Motorized Systems
| Feature | Description |
|---|---|
| Remote Control | Via Hand Unit |
| Smooth | Jerk-free transition |
| Wireless | Via radio remote |
| Integration | With camera system |
Combination with External ND
| Situation | Solution |
|---|---|
| Extreme light | Internal + External |
| Special effect | Grad ND external |
| Maximum | Combine both |
| Flexibility | As needed |
Limitations
| Limitation | Reality |
|---|---|
| Maximum | Typically 6-8 stops |
| Stepping | Discrete, not variable |
| Camera-dependent | Not retrofittable |
| Cost | Premium cameras |
Variable ND Alternative
| Aspect | Comparison |
|---|---|
| Internal fixed | Defined steps |
| External variable | Stepless |
| Quality | Internal usually better |
| Flexibility | Variable offers more |
Maintenance
| Task | Frequency |
|---|---|
| Cleaning | Rarely needed |
| Protection | Built-in |
| Calibration | From factory |
| Lifespan | Very long |
Documentation
| Element | Record |
|---|---|
| ND level | For each shot |
| Combination | If with external |
| Continuity | Matching reference |
| Metadata | Automatic |
Best Practices
| Practice | Reason |
|---|---|
| ND before Iris | Preserve DoF |
| Choose FSND | Avoid IR issues |
| Document | For post-production |
| Know the stops | Work faster |
Today
Internal ND wheels are a standard feature of professional cinema cameras. They enable fast, precise exposure control without compromising optical quality. From run-and-gun to studio work, the internal ND makes a difference for efficient workflow and consistent results.