Lghtmtr vs ZoneCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Lghtmtr
This app provides a minimalist light meter to help users determine ideal exposure settings for photography. It visually demonstrates the relationship between ISO, aperture, and shutter speed, making it intuitive for learning photographers.
- Minimalist light meter
- Intuitive exposure settings
- Visual feedback
- Adjustable ISO, aperture, shutter speed
- Camera profile customization
- Scene reference with readings
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Lghtmtr is a beautifully simple light meter that helps you find — and understand — the ideal exposure settings for a scene. Built for film photographers and anyone learning the craft, it makes the relationship between ISO, aperture, and shutter speed feel intuitive and the visual feedback helps reinforce the connection between them. Take a reading, get your settings, and start exploring. Adjust one value and the others respond instantly. Lock settings to experiment and see how each change affects your exposure. You can easily add camera profiles to the app to limit the possible values to what's most relevant to your camera and lens combination. With a visual reference of the scene behind every reading, Lghtmtr helps you shoot with clarity and confidence.
ZoneCalc
This app assists photographers in precisely calculating exposure and tonal placement using Ansel Adams' Zone System. It offers features for metering, reciprocity correction, and development adjustments, with options for multi-point measurements and data export.
- Zone System exposure calculation
- Multi-point metering
- Reciprocity correction
- Development adjustment recommendations
- Film-specific development times
- Calculation history and export
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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.
Screenshots
Verdict
The clearest difference is rating: ZoneCalc at 5.0 against Lghtmtr's 4.5. ZoneCalc also leads on update cadence (every 3 weeks vs every 4 months). Lghtmtr's advantage is monetization model (free vs freemium) and ratings volume (129 vs 2). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Lghtmtr sells 1 one-off in-app purchase and ZoneCalc sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
ZoneCalc holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Lghtmtr has 129 ratings behind it against 2, so its average is the more settled of the two.
Lghtmtr ships an update every 4 months, ZoneCalc every 3 weeks. The most recent releases landed on October 14, 2026 and October 12, 2026 respectively.
| Parameter | Lghtmtr | ZoneCalc |
|---|---|---|
| Price | Free | Free |
| Rating | 4.5 (129 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 79.7% of reviews | — |
| Number of ratings | 129 — better | 2 |
| Update frequency | Every 4 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free — better | Freemium |
| Devices | iPhone | iPhone |
| Requires iOS | 17.5 — better | 17.6 |
| Further details — not scored | ||
| Size | 25 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Alexander Jacque | Juergen Suk |
Customer experience
Lghtmtr
ZoneCalc
In-app purchases
Lghtmtr
- Coffee tip$4.99
ZoneCalc
- ZoneCalc Pro$3.99









