Film Photography Calculators
Free tools for the arithmetic film photographers run on the back of a hand: reciprocity, exposure, depth of field, stock comparison, a full reciprocity chart, and a lens filter finder. Nothing to install, nothing to sign up for.
These run entirely in your browser. The reciprocity and comparison tools pull from the same 668-stock catalog that ships inside the Zone Light Meter app, so the numbers match what you get in the field. Pick a tool below.
Reciprocity failure calculator
Pick your film stock, enter the metered time, and get the corrected exposure using that stock's measured reciprocity exponent.
Exposure and EV calculator
Convert any ISO, aperture, and shutter into an EV, then read off every equivalent aperture and shutter pair at that exposure.
Depth of field and hyperfocal calculator
Enter focal length, aperture, and subject distance for any format and get the near limit, far limit, and hyperfocal distance.
Film stock comparison
Put two to four film stocks side by side and compare ISO, type, brand, reciprocity, and availability at a glance.
Reciprocity failure chart
The long-exposure correction exponent for every film stock in one sortable, searchable table. Find your film or see which stocks need the most correction after dark.
Lens filter thread finder
Look up the filter diameter for any lens, or list every lens that takes a given size, so you buy the right polarizer or ND the first time.
Want all of this in your pocket, plus live metering off the camera? Zone Light Meter for Android runs every one of these calculations against a real light reading and logs the result.