Comparison

Heliosy vs ZoneCalc

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Heliosy

This app helps you track the sun's position for any day and location. It's useful for photographers planning shoots, real estate agents assessing sunlight, or builders choosing optimal locations for outdoor pools. Visualize sun paths through various displays like live camera, 3D compass, or maps.

Highlights
  • Sun path tracking for current or custom locations
  • Visualize sun path on live camera
  • 3D compass sun path display
  • Sun path on map view
  • Golden hour and blue hour identification
  • Twilight times display
  • Sun path graph
Features
Read full description

Heliosy is about Sun. More precisely, it is about sun path. Heliosy application tracks sun position for today or any other given day, at your current location or at any custom location. Heliosy application has many uses. Here are examples of them: - As a photographer, I use Heliosy application to prepare a shooting. I can go at a location and see when the sun will be at the place I want it to be. - As a rental agent, I can check how long during the day this room will get sun thru its window - As an outdoor swimming pool builder, I can check best pool location away of building sunshade. Heliosy provides you with many displays of sun path: - Magic: an immediate access to some magic moments like 'golden hour' or 'blue hour' - Twilights: show special moment of the day at dawn and dusk - Path: show sun path on live camera view - Compass: show sun path on a live 3D compass - Map: show sun path on map - Graph: show graph of sun path

About

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.

Highlights
  • Zone System exposure calculation
  • Multi-point metering
  • Reciprocity correction
  • Development adjustment recommendations
  • Film-specific development times
  • Calculation history and export
Features
Read full description

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

Heliosy4 screens
ZoneCalc4 screens

Verdict

The call

The clearest difference is price: ZoneCalc at Free against Heliosy's $2.99. ZoneCalc also leads on update cadence (every 3 weeks vs every 4 months). Heliosy's advantage is in-app purchases (none vs 1) and device support (3 vs 1). On ads 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

CostPrice · In-app purchases · Ads · Monetization

ZoneCalc is free to download; Heliosy costs $2.99 up front. ZoneCalc sells 1 one-off in-app purchase. Heliosy asks for nothing beyond the download.

UpkeepUpdate frequency

Heliosy ships an update every 4 months, ZoneCalc every 3 weeks. The most recent releases landed on September 19, 2026 and September 9, 2026 respectively.

Scorecard6 real differences · 4 level
Heliosy versus ZoneCalc: the parameters behind the verdict, then further details
ParameterHeliosyZoneCalc
Price$2.99Free — better
Rating—5.0 (2 ratings) — better
Positive reviews0.0% of reviews—
Number of ratings—2 — better
Update frequencyEvery 4 monthsEvery 3 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFreemium — better
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS15.0 — better17.6
Further details — not scored
Size2 MB3 MB
Age rating4+4+
DeveloperJean-Christoph KAISERJuergen Suk

Customer experience

Heliosy

Written reviews1 reviews
Positive0.0%
Neutral100.0%
Negative0.0%

ZoneCalc

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Heliosy

No in-app purchases

1 purchases

ZoneCalc

One-time1
  • ZoneCalc Pro$3.99

Questions

Is Heliosy free?
Heliosy costs $2.99, with no in-app purchases.
Is ZoneCalc free?
ZoneCalc is free to download, with in-app purchases available.
Do Heliosy or ZoneCalc have ads?
Neither Heliosy nor ZoneCalc shows ads.
Which is updated more often, Heliosy or ZoneCalc?
Heliosy ships an update every 4 months, and ZoneCalc every 3 weeks. Most recently, Heliosy was updated on September 19, 2026 and ZoneCalc on September 9, 2026.

Other comparisons