# Video tachometer vs Light Spectrometer Wavelength

The clearest difference is rating: Video tachometer at 4.6 against Light Spectrometer Wavelength's 4.2. Video tachometer also leads on review sentiment (85% vs 73%). On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. Video tachometer sells 1 one-off in-app purchase and Light Spectrometer Wavelength sells 4 in-app purchases, starting at $0.99 per month. Whichever you choose, the download price is not the number that matters.

Video tachometer holds the better App Store score, 4.6 against 4.2. Both are backed by a comparable volume of ratings — 84 and 96 respectively. Written reviews point the same way: 85% of Video tachometer's written reviews are positive against 73% of Light Spectrometer Wavelength's.

Video tachometer ships an update every 3 months, Light Spectrometer Wavelength every 2 months. The most recent releases landed on October 22, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Video tachometer | Light Spectrometer Wavelength |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (84 ratings)](https://appshunter.io/ios/app/video-tachometer/id1492583587/reviews)** | [4.2 (96 ratings)](https://appshunter.io/ios/app/light-spectrometer-wavelength/id6450930820/reviews) |
| Number of ratings | 84 | **96** |
| Positive reviews | **84.9% of reviews** | 72.7% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 2 months** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 5 MB | 43 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Dmitriy Kharutskiy](https://appshunter.io/developer/817385891) | [Contechity AB](https://appshunter.io/developer/1649290454) |

## What reviewers say

### Video tachometer

[App page](https://appshunter.io/ios/app/video-tachometer/id1492583587)

This app uses slow-motion video to create a strobe light effect, allowing you to measure rotational speeds. It records video with detailed information like frame rate and exposure, and offers customizable text overlays.

**Highlights:** Strobe light effect simulation, Rotational speed measurement (RPM/Hz), Slow-motion video recording, Customizable text overlays on video, Adjustable frame rate and exposure, Records 4K video (if supported)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full version | $2.99 | one-time |

**What reviewers like**

- 👍 Easy to use
- 💡 Clever approach
- 🚀 Works beautifully
- 👍 Very handy
- 👍 Accurate measurements

**What reviewers complain about**

- 💸 Too much in paid version
- 💰 Free version limited
- 🤔 Confusing settings initially
- 👎 Unclear about recording
- 👎 No built-in video recording

**Reported bugs**

- Does not read anything
- Pop-ups for paid features
- Interface visible in screen recording

**Requested features**

- Ability to record video
- Slow phase shift mode
- Improved UI for initial setup
- Long press for gradual increment/decrement


### 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 Video tachometer free?

Video tachometer is free to download, with in-app purchases available.

### Is Light Spectrometer Wavelength free?

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

### Which has better reviews, Video tachometer or Light Spectrometer Wavelength?

Video tachometer is rated higher. Video tachometer averages 4.6 out of 5 from 84 ratings, while Light Spectrometer Wavelength averages 4.2 from 96 ratings.

### Do Video tachometer or Light Spectrometer Wavelength have ads?

Neither Video tachometer nor Light Spectrometer Wavelength shows ads.

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

Video tachometer ships an update every 3 months, and Light Spectrometer Wavelength every 2 months. Most recently, Video tachometer was updated on October 22, 2026 and Light Spectrometer Wavelength on October 24, 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.*