ISO, aperture, shutter angle, and frame rate → effective time, log exposure, EV-style value, cine ND labels, and one-stop equivalent trades
Exposure log₂ L = log₂(t·ISO/N²) matches between equivalent correct exposures. EV-style number is for ballpark only (APEX-scaled, offset vs ISO 100). ND labels follow common 0.3 density ≈ 1 stop rings (ND0.3, ND0.6…).
"ND strength needed" is scene-specific; use L together with a meter or false color. The ND filter tool balances shutter changes at constant exposure.
| change | result | use when |
|---|---|---|
| 2× ISO | ISO 1600 | one stop up without touching T or f |
| 2× time | 41.67 ms · 1/24 s | wider / slower shutter, same f, same ISO |
| 1 stop open (÷√2 f) | f/2.0 | same t, same ISO |