Industry-standard base sensitivity for professional digital cinema cameras like ARRI ALEXA – the optimal ISO setting where the sensor delivers maximum dynamic range, cleanest image, and best signal-to-noise ratio without any digital gain or push/pull processing.
What is Native ISO 800?
Native ISO 800 is the base sensitivity of many professional digital cinema cameras, particularly ARRI ALEXA. At this value, the sensor delivers optimal image quality with maximum dynamic range and minimal noise.
Basic Principle
| Aspect | Description |
|---|---|
| Definition | Base sensitivity |
| Significance | Optimal operating point |
| Dynamic Range | Maximum |
| Noise | Minimum |
Cameras with Native ISO 800
| Camera | Native ISO |
|---|---|
| ARRI ALEXA Classic | 800 |
| ARRI ALEXA Mini | 800 |
| ARRI ALEXA LF | 800 |
| ARRI ALEXA 35 | 800 |
Why 800?
| Factor | Description |
|---|---|
| Sensor Design | Optimized for this value |
| Dynamic Range | Maximum stops |
| Signal-to-Noise Ratio | Best ratio |
| Tradition | 500T film equivalent |
Dynamic Range at ISO 800
| Range | Stops |
|---|---|
| Above Middle Gray | ~7 stops |
| Below Middle Gray | ~7 stops |
| Total | ~14+ stops |
| Optimally Distributed | Yes |
ISO Adjustment
| ISO | Effect |
|---|---|
| < 800 | Pull (less gain) |
| 800 | Native (optimal) |
| > 800 | Push (more gain) |
| Any Change | Compromise |
Push vs. Pull
| Direction | Advantage | Disadvantage |
|---|---|---|
| Push (Higher) | More sensitivity | More noise |
| Pull (Lower) | Less noise | Less sensitivity |
| Native | Optimal | None |
Exposure at ISO 800
| Situation | Typical Aperture |
|---|---|
| Sunny Day | T11-T16 (with ND) |
| Overcast | T4-T5.6 |
| Interior (Natural Light) | T2.8-T4 |
| Dimly Lit | T1.4-T2 |
Light Requirement
| Setting | Footcandles (fc) |
|---|---|
| Bright Day | 10,000+ |
| Overcast | 1,000-5,000 |
| Interior | 50-200 |
| Low Key | 10-50 |
EI vs. ISO
| Term | Description |
|---|---|
| ISO | Sensor sensitivity |
| EI | Exposure Index |
| On ARRI | EI is used |
| In Practice | Interchangeable |
Workflow
| Step | Description |
|---|---|
| 1 | Start at ISO 800 |
| 2 | Set lighting accordingly |
| 3 | Use ND for daylight |
| 4 | Push only when necessary |
ND Filters in Daylight
| ND | Aperture Stops | For |
|---|---|---|
| 0.3 | 1 Stop | Slightly overcast |
| 0.6 | 2 Stops | Overcast |
| 0.9 | 3 Stops | Bright day |
| 1.2 | 4 Stops | Sunny |
Comparison with Other Cameras
| Camera | Native ISO |
|---|---|
| ARRI | 800 |
| RED (Low) | 800 |
| Sony Venice (Low) | 500 |
| Blackmagic (Low) | 400 |
Dual Native ISO (Sony, Panasonic)
| System | Low | High |
|---|---|---|
| Sony Venice | 500 | 2500 |
| Panasonic VariCam | 800 | 5000 |
| Blackmagic | 400 | 3200 |
| ARRI | 800 (only) | — |
ARRI Without Dual ISO
| Aspect | Description |
|---|---|
| Design Philosophy | One optimal point |
| Advantage | Consistent quality |
| Disadvantage | Less low-light flexibility |
| Solution | More light |
Best Practices
| Practice | Reason |
|---|---|
| Stay at 800 | Optimal quality |
| Adjust lighting | Instead of changing ISO |
| Push with caution | Quality degradation |
| Test if needed | For special looks |
Today
Native ISO 800 is the gold standard in professional cinematography. ARRI has perfected this value, and despite dual-native ISO alternatives, the concept of an optimized base ISO remains relevant. For the best image quality, lighting designed for Native ISO is the preferred method.