# BTZS ExpoDev vs Zone System

The clearest difference is price: Zone System at $1.99 against BTZS ExpoDev's $24.99. Zone System also leads on update cadence (every 9 days vs every 12 months) and review sentiment (100% vs 83%). BTZS ExpoDev's advantage is iOS requirement (13.7 vs 17). On ratings volume, ads, in-app purchases and monetization model there is nothing between them.

BTZS ExpoDev costs $24.99 and Zone System $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Zone System holds the better App Store score, 5.0 against 4.8. Both are backed by a comparable volume of ratings — 5 and 3 respectively. Written reviews point the same way: 83% of BTZS ExpoDev's written reviews are positive against 100% of Zone System's.

BTZS ExpoDev ships an update every 12 months, Zone System every 9 days. The most recent releases landed on October 7, 2026 and October 2, 2026 respectively.

## The numbers

| Metric | BTZS ExpoDev | Zone System |
| --- | --- | --- |
| Price | $24.99 | **$1.99** |
| Rating | [4.8 (5 ratings)](https://appshunter.io/ios/app/btzs-expodev/id507385770/reviews) | **[5.0 (3 ratings)](https://appshunter.io/ios/app/zone-system/id6741873549/reviews)** |
| Number of ratings | **5** | 3 |
| Positive reviews | 83.3% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 9 days** |
| Monetization | Paid | Paid |
| Size | 16 MB | 12 MB |
| Requires iOS | **13.7** | 17 |
| Devices | iPhone, iPod | **iPhone, iPad, Apple Watch, Vision Pro** |
| Age rating | 4+ | 4+ |
| Developer | [TinyOctopus, LLC](https://appshunter.io/developer/507385773) | [Davin Nguyen](https://appshunter.io/developer/1680398335) |

## What reviewers say

### BTZS ExpoDev

[App page](https://appshunter.io/ios/app/btzs-expodev/id507385770)

This app helps traditional film photographers accurately expose black and white film using custom film test data. It calculates precise exposures and development times in the field for consistent results and easier darkroom printing.

**Highlights:** Exposure record keeping, Film Profile, lens, and filter management, Incident and Zone System metering support, Depth of Field calculator, Reciprocity failure adjustments, Integrated exposure timer

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Zone System

[App page](https://appshunter.io/ios/app/zone-system/id6741873549)

This tool simplifies Ansel Adams' exposure and development method for photographers. It helps measure shadows and highlights, calculate aperture and development times, and preview results with film stock presets.

**Highlights:** Measure shadows and highlights, Aperture and development calculations, Preview results with film presets, ISO and EV calculations, Simplified Zone System application

**Features:** macOS Compatibility, Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is BTZS ExpoDev free?

BTZS ExpoDev costs $24.99, with no in-app purchases.

### Is Zone System free?

Zone System costs $1.99, with no in-app purchases.

### Which has better reviews, BTZS ExpoDev or Zone System?

Zone System is rated higher. BTZS ExpoDev averages 4.8 out of 5 from 5 ratings, while Zone System averages 5.0 from 3 ratings.

### Do BTZS ExpoDev or Zone System have ads?

Neither BTZS ExpoDev nor Zone System shows ads.

### Which is updated more often, BTZS ExpoDev or Zone System?

BTZS ExpoDev ships an update every 12 months, and Zone System every 9 days. Most recently, BTZS ExpoDev was updated on October 7, 2026 and Zone System on October 2, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*