The ISO value at which a camera operates without additional amplification, delivering optimal image quality. ARRI Alexa 35: ISO 800/3200; Canon C70: ISO 850/4500.
Technical Details
The term originates from digital technology and describes the point at which analog-to-digital conversion occurs without additional amplification. Many professional cameras feature Dual Native ISO systems: the ARRI Alexa 35 operates at ISO 800 and ISO 3200, the Canon C70 at ISO 850 and ISO 4500. When deviating from the Native ISO, the signal is either artificially amplified (higher values) or electronically attenuated (lower values), leading to a poorer signal-to-noise ratio. The sensor reads identical raw data but alters the internal gain of the readout electronics.
History & Development
The concept of Native ISO developed from 2005 onwards with the transition to digital cinema cameras. The first RED ONE (2007) established ISO 320 as its native value, while Arri set the standard at ISO 800 with the Alexa (2010). Dual Native ISO systems emerged in 2017 with the Panasonic EVA1, enabling two optimized sensitivity levels per sensor. Sony introduced Native ISO 4000 for the first time in 2019 with the FX9, revolutionizing nighttime shooting without additional lighting.
Practical Application in Film
Cinematographers use Native ISO as a starting point for lighting planning. Christopher Nolan shot "Tenet" (2020) mostly at the native ISO 500 of the IMAX cameras to achieve maximum image quality. For low-light scenes in "Blade Runner 2049" (2017), DoP Roger Deakins deliberately worked at the upper Native ISO limit of the ARRI Alexa 65. Exceeding the Native ISO by more than two stops results in visible noise, which is why professional workflows adjust lighting accordingly rather than increasing the ISO.
Comparison & Alternatives
Native ISO differs from the maximum usable ISO in its noise characteristics. While the ARRI Alexa delivers usable images up to ISO 3200, it achieves optimal quality only at its Native ISO 800. Extended ISO modes operate solely through software amplification and noticeably degrade image quality. When choosing a camera, the Native ISO often determines its suitability for different applications: cameras with a low Native ISO are ideal for studio productions, while high values are suited for documentary work or available-light scenarios.