Lumo Light Meter vs ZoneCalc

A light meter, refined for film. Lumo brings precise exposure to your pocket, designed for photographers who care about every frame. Whether you're loading a roll of 35mm or composing on the ground glass, Lumo gives you the readings you need and nothing you don't. Two ways to meter Spot mode for narrow, deliberate readings of a single tone. Matrix mode for evaluative readings across the whole scene. Switch instantly, depending on the shot in front of you. Matched to your camera Choose from a library of film cameras and calibrate Lumo to the body you're shooting. Your meter, your camera, the same readings — frame after frame. Hold and capture Lock a reading to recompose, plan a shot, or compare values across the scene. Capture exposures as you work and return to them when you're ready to release the shutter. Made to disappear A quiet interface that stays out of your way. Custom themes let you tune Lumo to the moment — bright for the studio, dark for the darkroom, low-key on the street. Made for film photographers • Hobbyists and pros shooting 35mm or medium format • Students learning exposure, the Zone System, and the discipline of analog • Anyone who'd rather feel the camera than fight the meter Lumo. Meter every frame with care.

ZoneCalc — Zone System Calculator ZoneCalc is a precision tool for large format, medium format and 35 mm photography following Ansel Adams' Zone System. Built for photographers who work with a spot meter, develop their own negatives, and want full control over exposure and tonal placement. METERING In Classic mode, enter the shutter speed for the deepest shadow with detail (Zone II) and the brightest highlight with detail (Zone VIII). ZoneCalc returns the shutter speed for Zone V — 18 % middle gray — the exposure you set on the camera. Multi mode accepts any number of measurement points across the scene. The app auto-assigns each point to a zone; drag pins on the zone strip to express your creative placement intent. RECIPROCITY For exposures above one second, the Schwarzschild effect is corrected automatically: t_corr = t_nom ^ p, using the film-specific exponent. The corrected camera time appears directly in the result card. The shutter speed list extends to 30 minutes. Films with reciprocity data: Ilford HP5+, FP4+, Delta 100/400, Kodak Tri-X, T-Max 100/400, Kodak Portra 160/400/800, Leica Monopan. N-RATING & DEVELOPMENT ZoneCalc compares the scene's dynamic range against the film's usable latitude and proposes a development adjustment — N−2 through N+2. For each film, concrete times are shown for common developers: D-76, Rodinal, HC-110, XTOL, ID-11, T-Max Dev — with dilutions per Massive Dev Chart and manufacturer recommendations. HISTORY & EXPORT Every calculation can be saved with a note and the chosen developer; two entries can be compared side by side. The complete result — shutter speed, reciprocity, N-rating and development times — exports as an image for the darkroom or for sharing via AirDrop, message or mail. DESIGN The interface follows the visual language of classic Leica instruments: monospaced typography, warm amber accent, hard edges instead of rounded corners. Fully localized in English and German, all-dark throughout — optimized for darkroom and field use. ZONECALC PRO Classic two-point metering with Zone V calculation and the zone strip are free. The one-time Pro upgrade unlocks: — Multi-point metering with interactive zone assignment — Reciprocity correction and N-rating — Development recommendations with times per developer — Save, compare and image export One app, no subscriptions, no data collection. All calculations run locally on device.