A photographer's complete exposure toolkit: live light meter, exposure triangle, film reciprocity, bracketing calculator, filter factor correction, ND, flash, color temperature, zone system, recipe compare, and field recipe book.
Lumen Forge gives digital and film photographers a single offline tool for every exposure decision — from reading a live scene on the meter to correcting for reciprocity failure on 30-second film exposures. No account, no network, no ads.
17 Wratten filters — yellows (6, 8/K2, 9, 12, 15/G), oranges (21, 22), reds (25/A, 29/F, 70), greens (11, 13, 58), blue (47), 80A conversion, UV/1A, CPL — with daylight and tungsten factors. Accurate to Kodak B-3, Ilford B&W Guide, and Ansel Adams' published tables.
Stacks up to 3 filters, interpolates factor at any Kelvin between 3200 and 5500 K, and pulls live meter reading for instant correction.
The Hyperfocal calculator now includes a full DoF table across all standard full-stop apertures. Tap any row to jump to that aperture. See near limit, far limit, and total depth of field at a glance for the current focal length and subject distance.
Select any two saved lighting setups and tap Compare to see the EV difference, aperture stop delta, shutter stop delta, ISO ratio, and Kelvin difference side by side. Know exactly how your studio A and B setups differ before you shoot.
Hyperfocal + DoF table, Cinema 180° shutter, Sunny f/16, Macro reciprocity, Polarizer predictor, Star Trail (NPF rule), Film Reciprocity, Bracketing, and now Filter Factor — all offline, no subscription.
25 film stocks — Ilford HP5/FP4/Delta, Kodak T-Max/Tri-X/Portra, Fuji Acros/Velvia, Fomapan, Rollei, ADOX — with the Schwarzschild correction formula. Enter your metered time; get the corrected exposure and a per-film quick-reference table.
Plan AEB sequences before you set up your tripod. Export all saved recipes as a CSV file — compatible with Numbers, Excel, and any spreadsheet app.
This image shows the current iPhone app interface prepared for review-facing screenshots.
Lumen Forge is fully offline. It collects no data, requires no account, and contains no advertising or analytics SDKs. Lighting recipes are stored locally on your device using SwiftData. The only permission requested is camera access for the live meter — and every other tab works without it.