Sony ZV-E1 Dual Base ISO Calculator (S-Log3 & S-Cinetone)

Stop guessing your exposure. The Sony ZV-E1 (and A7S III / FX3) utilises a Dual Base ISO architecture. This means there are two distinct ISO settings where the sensor performs at its absolute peak, offering maximum dynamic range and minimal noise.

Use this cheat sheet to find the correct 'First Base' and 'Second Base' ISOs for every shooting mode, including S-Log3, S-Cinetone, and RAW Photography.

Dual Base ISO Calculator

For Sony ZV-E1, A7S III & FX3

S-Log3 (Video)
Stills (RAW)
S-Cinetone
S-Log3 Base Levels
First Base ISO ISO 640
Cleanest possible image. 15+ Stops DR.
Ramp Up Zone 800 - 10k
Avoid. Noise increases steadily.
Second Base ISO ISO 12,800
High Gain circuit engages. Noise drops significantly.
Noise Floor Visualizer
640 (Clean) 10,000 (Peak Noise) 12,800 (Clean)
Photography Mode (Standard)
First Base ISO ISO 80
Native sensitivity. Deepest shadows.
Gain Ramp 100 - 1250
Standard gain increase.
Second Base ISO ISO 1,600
High Base engages. Cleaner than 1000.
Picture Profile 11 (PP11)
First Base ISO ISO 100
Daylight standard.
Second Base ISO ISO 2,000
High Base engages. Ideal for indoors.
12MP Full Frame BSI Sensor

How Dual Base ISO Works (Simplified)

Conventional cameras have one native ISO (usually 100). As you increase the ISO dial, you are simply adding digital gain—like turning up the volume on a static-filled radio. The higher you go, the louder the noise.

The ZV-E1 sensor has two separate amplifier circuits:

  1. Low Gain Circuit (First Base): Optimized for bright conditions and maximum dynamic range.

  2. High Gain Circuit (Second Base): Optimized for low light.

When you switch from ISO 10,000 to ISO 12,800 (in S-Log3), the camera physically switches to the "High Gain" circuit. This resets the noise floor, giving you a cleaner image at 12,800 than at 10,000.

The "Noise Zone" Rule When shooting video in S-Log3, ISO 10,000 is the noisiest low gain setting on the camera. It is the absolute limit of the Low Gain circuit.

  • Rule of thumb: If your exposure meter suggests ISO 8,000 or 10,000, do not shoot.

  • The Fix: Bump your ISO up to 12,800. You will get a cleaner image. If the image is now too bright, close your aperture slightly or use an ND filter to compensate.

Does this apply to other cameras? Yes. Since the Sony ZV-E1, Sony A7S III, and Sony FX3 all share the exact same 12MP BSI sensor, this cheat sheet applies perfectly to all three cameras.