ISO/Film Speed Converter
Convert between ASA, ISO, DIN, GOST, and calculate exposure values for film and digital photography.
Professional Photography Standard
ASA
f/
Lens aperture
sec
1/125 sec = 0.008
EV
Exposure Value
EI
Effective speed used
mm
Bellows extension
mm
Lens focal length
Converted Film Speed
ASA 400 = ISO 400/27° = DIN 27 = GOST 360
f/5.6 at 1/125s • EV 12 • 35mm Color Negative
BSI 400 • JIS 400 • Weston 320 • GE 400