Film Grain ISO Equivalent Calculator
Film Grain ISO Equivalent
Convert between analog film grain sizes and digital ISO equivalents, and estimate visible noise levels for film simulation.
Formula
Effective ISO = Base ISO x 2^(push stops); Visible Grain = Base Grain + (Push x 2) x Format Reduction; Digital Equiv = Effective ISO x Format Grain Reduction
Frequently Asked Questions
Does pushing film increase grain?
Yes. Pushing film (underexposing and overdeveloping) increases grain noticeably. Each stop of push increases visible grain. Pulling film reduces grain slightly.
How does film format affect grain?
Larger film formats show less visible grain when printed at the same size because less enlargement is needed. Medium format shows about half the grain of 35mm.
What film stock has the finest grain?
Among common stocks, Kodak Portra 160 and Fuji Velvia 50 have extremely fine grain. For black and white, Ilford Delta 100 and Kodak T-Max 100 are very fine-grained.