ZoneCalc vs Z

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.

Expose for the shadows, develop for the highlights. Z-Stop is an iPhone spot meter true to this Zone System principle. Shoot black-and-white film with the Zone System, no external meter needed. [ Sound familiar? ] - Still guessing exposure by feel? - Wasting expensive film on bad exposures? - Carrying a spot meter for a camera with no meter? - Metered a shadow and got a picture that was too bright? - Forgetting where you metered by the time you develop? For about the price of a roll of black-and-white film, you can leave these behind. Meter one shadow with your iPhone, and Z-Stop shows the shutter and aperture that make it Zone 3, in 1/2-stop steps. With Pro, one tap on "Save" keeps the scene as a record image. [ The Zone System ] Worked out by Ansel Adams and Fred Archer around 1940. It divides tones into 11 steps, from black (Zone 0) to white (Zone 10), one stop apart. Detail is clearest from Zone 3 to Zone 7. Zone 3 : darkest shadow with full texture Zone 4 : foliage and stone in shade Zone 5 : middle gray (18% gray card) Zone 6 : sunlit light skin, light stone Zone 7 : brightest textured areas Expose so the shadow detail stays on the film, then set development so the highlights land where you want them. [ A meter only knows Zone 5 ] Any reflected meter renders what it reads as middle gray (Zone 5). Shoot a shadow at its reading and it turns gray. To place a shadow on Zone 3, give 2 stops less than the reading. That is why spot metering matters: a wide reading mixes one shadow with other tones. [ Why Z-Stop ] Finding a shadow, subtracting 2 stops, converting to real settings, and bracketing by half stops is slow and error-prone. * No spot meter or DSLR required - A reflected spot meter that reads only inside a small circle on screen. * Tells you if a shadow is good for Zone 3 - It checks how even the spot is (deviation): green "Z3 OK" if usable, red "Re-meter" if texture or an edge is mixed in. * No hunting for where to meter - "Find Zone 3" points only to usable spots. - With no Zone 3 it looks for Zone 4; with neither it says "Don't shoot", so you don't waste film. * No mental math - Shows values that match your body's shutter speeds and your lens apertures. - Values you cannot set get a red warning. * Ready for half-stop differences - Five steps in 1/2 stops, from the reading to -2 stops. - Full-stop shutters: unsettable steps are gray; "By aperture" brackets the aperture. * A steady reference - Exposure locks at the first reading, so up to five spots compare fairly. * No notebook needed (Pro) - The record image keeps the screen, readings, shutter, and aperture, so you can check your Zone 3 spot after developing. * See the gray before you shoot - B&W preview shows what tone a red sign or green awning will become. [ How to use ] 1. Tap a shadow. 2. Tap a green "Z3 OK" box to set the anchor, or press "Find Zone 3" at the lower left. 3. Fix the aperture ("By shutter") or the shutter speed ("By aperture"), and read the five steps. In theory Zone 3 is -2 stops, but the right step shifts by half a stop with film, EI, development, and printing. Choose a main frame and a sub frame. 4. With Pro, press "Save" to keep the record image in the "Z-Stop" album. [ Free and Pro ] Metering, Find Zone 3, Zone 3 anchor, five 1/2-stop steps, By shutter, By aperture, B&W preview, and settings are free. Pro (in-app purchase, yearly subscription) unlocks record saving. Setup : EI, aperture, ND, camera body (SLR, RF, medium/large format) Privacy : no internet except the subscription check with Apple; no ads or analytics; video stays on your iPhone Terms of Use : https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ * Z-Stop calculates from the brightness of the iPhone's standard (1x) camera. * Development for the highlights is up to you. * Not for important shoots you can't repeat (weddings, trips, paid work) at first. * Test with a roll or two, set it up, and bracket until you know your results.