# Photometrics vs ETC Library

The clearest difference is review sentiment: Photometrics at 67% against ETC Library's 0%. Photometrics also leads on rating (4.3 vs 3.8) and iOS requirement (15.6 vs 17). ETC Library's advantage is update cadence (every 3 months vs every 5 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Photometrics holds the better App Store score, 4.3 against 3.8. Both are backed by a comparable volume of ratings — 7 and 4 respectively. Written reviews point the same way: 67% of Photometrics's written reviews are positive against 0% of ETC Library's.

Photometrics ships an update every 5 months, ETC Library every 3 months. The most recent releases landed on October 23, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Photometrics | ETC Library |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.3 (7 ratings)](https://appshunter.io/ios/app/photometrics/id733009338/reviews)** | [3.8 (4 ratings)](https://appshunter.io/ios/app/etc-library/id733300518/reviews) |
| Number of ratings | **7** | 4 |
| Positive reviews | **66.7% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 months** |
| Monetization | Free | Free |
| Size | 105 MB | 71 MB |
| Requires iOS | **15.6** | 17 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ARRI Group](https://appshunter.io/developer/733009342) | [Electronic Theatre Controls, Inc.](https://appshunter.io/developer/318210459) |

## What reviewers say

### Photometrics

[App page](https://appshunter.io/ios/app/photometrics/id733009338)

Access photometric data for ARRI light fixtures, including discontinued models and electronics ballasts. Features include illuminance, beam angle, luminous distribution graphs, and light properties. Tools for comparison, DMX calculations, and product catalogs are also available.

**Highlights:** Photometric data (illuminance, beam angle), Luminous distribution graphs, Light properties (CRI, TM30, TLCI), Metric and Imperial units, Camera exposure information, Project creation and preset saving, Lamphead comparison tool

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

**In-app purchases:** none


### ETC Library

[App page](https://appshunter.io/ios/app/etc-library/id733300518)

Access technical documentation for a wide range of products. Browse and share datasheets, application sheets, and brochures organized by product family. This virtual binder provides quick access to essential product information.

**Highlights:** Access to hundreds of technical documents, Organized by product family and category, View datasheets, application sheets, and brochures, Easy document sharing, Offline access to downloaded documents

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Photometrics free?

Photometrics is free to download, with no in-app purchases.

### Is ETC Library free?

ETC Library is free to download, with no in-app purchases.

### Which has better reviews, Photometrics or ETC Library?

Photometrics is rated higher. Photometrics averages 4.3 out of 5 from 7 ratings, while ETC Library averages 3.8 from 4 ratings.

### Do Photometrics or ETC Library have ads?

Neither Photometrics nor ETC Library shows ads.

### Which is updated more often, Photometrics or ETC Library?

Photometrics ships an update every 5 months, and ETC Library every 3 months. Most recently, Photometrics was updated on October 23, 2026 and ETC Library on October 29, 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.*