# Theta vs Light Spectrometer Wavelength

The clearest difference is rating: Theta at 5.0 against Light Spectrometer Wavelength's 4.2. Theta also leads on in-app purchases (none vs 7) and review sentiment (100% vs 71%). Light Spectrometer Wavelength's advantage is ratings volume (96 vs 1). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Light Spectrometer Wavelength sells 4 in-app purchases, starting at $0.99 per month. Theta asks for nothing beyond the download.

Theta holds the better App Store score, 5.0 against 4.2. That said, the two scores are not equally well evidenced: Light Spectrometer Wavelength has 96 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of Theta's written reviews are positive against 71% of Light Spectrometer Wavelength's.

Theta ships an update monthly, Light Spectrometer Wavelength every 2 months. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Theta | Light Spectrometer Wavelength |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/theta-meter-light/id1077931723/reviews)** | [4.2 (96 ratings)](https://appshunter.io/ios/app/light-spectrometer-wavelength/id6450930820/reviews) |
| Number of ratings | 1 | **96** |
| Positive reviews | **100.0% of reviews** | 70.6% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Monthly** | Every 2 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 13 MB | 43 MB |
| Requires iOS | **11.0** | 15.0 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 12+ | 4+ |
| Developer | [Mikhail Fedorov](https://appshunter.io/developer/714735606) | [Contechity AB](https://appshunter.io/developer/1649290454) |

## What reviewers say

### Theta

[App page](https://appshunter.io/ios/app/theta-meter-light/id1077931723)

This application connects to specialized devices to measure and display galvanic skin response. It utilizes Wi-Fi and Bluetooth 4.0BLE to collect data on skin conductance, providing insights into physiological responses.

**Highlights:** Galvanic skin response measurement, Wi-Fi connectivity, Bluetooth 4.0BLE connection, Skin conductance data display, Physiological response tracking

**In-app purchases:** none


### Light Spectrometer Wavelength

[App page](https://appshunter.io/ios/app/light-spectrometer-wavelength/id6450930820)

This application analyzes light to determine its dominant wavelength in nanometers, frequency in terahertz, and period length in femtoseconds. It provides real-time measurements and allows users to save their findings with notes. The app is designed for measuring colored light sources.

**Highlights:** Measures dominant wavelength (nm), Measures frequency (THz), Measures period length (fs), Real-time measurement, Save measurements with notes, Optional calibration

**Features:** Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Access | $0.99 | per month |
| Full access | $0.99 | per month |
| Full access | $4.99 | per year |
| Full access | $6.99 | one-time |


## Frequently asked questions

### Is Theta free?

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

### Is Light Spectrometer Wavelength free?

Light Spectrometer Wavelength is free to download, with in-app purchases available.

### Which has better reviews, Theta or Light Spectrometer Wavelength?

Theta is rated higher. Theta averages 5.0 out of 5 from 1 ratings, while Light Spectrometer Wavelength averages 4.2 from 96 ratings.

### Do Theta or Light Spectrometer Wavelength have ads?

Neither Theta nor Light Spectrometer Wavelength shows ads.

### Which is updated more often, Theta or Light Spectrometer Wavelength?

Theta ships an update monthly, and Light Spectrometer Wavelength every 2 months. Most recently, Theta was updated on November 2, 2026 and Light Spectrometer Wavelength on November 3, 2026.

---

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