Comparison

Libre Light Sensor vs Light Spectrometer Wavelength

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

Head to head
About

Libre Light Sensor

Measure ambient light levels in Lux using your iPhone's camera. Optimize sleep quality by understanding light exposure throughout the day and night.

Highlights
  • Measure light in Lux
  • Utilizes iPhone camera
  • Optimize sleep quality
  • Track light exposure
Read full description

Measure light levels in any environment. Libre Light Sensor leverages your iPhone's camera to calculate luminosity as measured in Lux. This allows you to determine how much light exposure your eyes are receiving when you wake up, during the day, and before bed in order to optimize your sleep quality.

About

Light Spectrometer Wavelength

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
Read full description

Measures light spectrum to determine the dominant wavelength in nm, frequency in THz and period length in fs. DOMINANT WAVELENGTH Dominant wavelength is a concept commonly used in the field of color science and perception. It refers to the wavelength of light that appears most prominent or dominant in a given color mixture or light source. In other words, it is the wavelength that our eyes perceive as the primary color in a mixture of different wavelengths. For light with only one wavelength, such as the light from a colored LED, the dominant wavelength corresponds to the wavelength of that light. KEY FEATURES • High accuracy • Real-time measurement • Measures light wavelength in nanometers (nm) • Measures light frequency in terahertz (Thz) • Measures light period length in femtoseconds (fs) • Easy to use • Save measurements with notes • Supports 40 languages, including english • Optional calibration for enhanced precision MEASURING 1. Find a white surface, such as a plain piece of white paper 2. Point your camera at the surface illuminated by your target light source 3. The app gives you accurate measurements in real-time LIMITATIONS Smartphone cameras have limitations when it comes to distinguishing between different very short, or very long wavelengths. More specifically, on many devices the accuracy below 465 nm and above 610 nm is very limited. This is due to the physical camera sensors in the devices. An automatic warning appears on the screen for these short and long wavelengths. WHITE LIGHT Note that is not meaningful to measure the dominant wavelength of white light as white light consists of a wide range of wavelengths, with no wavelength dominating. This app is made for measuring colored light. If you are interested in determining the color temperature of white light, please instead use our popular White Balance Kelvin Meter app. COLOR OF SURFACES If you want to measure the color of a surface or material, rather than of light, please instead use our popular Colorimeter Camera Color Meter app. Privacy Policy, https://spectrometer.contechity.com/pp.html End User License Agreement, https://spectrometer.contechity.com/eula.html CONTACT I value your feedback. Email me at apps@contechity.com with any suggestions or questions. Download the Spectrometer now!

Screenshots

Libre Light Sensor4 screens
Light Spectrometer Wavelength4 screens

Verdict

The call

The clearest difference is rating: Libre Light Sensor at 4.8 against Light Spectrometer Wavelength's 4.2. Libre Light Sensor also leads on in-app purchases (none vs 7) and review sentiment (82% vs 73%). Light Spectrometer Wavelength's advantage is device support (3 vs 1). On price, ratings volume, update cadence and 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

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

ReceptionRating · Positive reviews · Number of ratings

Libre Light Sensor holds the better App Store score, 4.8 against 4.2. Both are backed by a comparable volume of ratings — 113 and 94 respectively. Written reviews point the same way: 82% of Libre Light Sensor's written reviews are positive against 73% of Light Spectrometer Wavelength's.

UpkeepUpdate frequency

Libre Light Sensor ships an update every 5 weeks, Light Spectrometer Wavelength every 2 months. The most recent releases landed on October 7, 2026 and October 9, 2026 respectively.

Scorecard5 real differences · 5 level
Libre Light Sensor versus Light Spectrometer Wavelength: the parameters behind the verdict, then further details
ParameterLibre Light SensorLight Spectrometer Wavelength
PriceFreeFree
Rating4.8 (113 ratings) — better4.2 (94 ratings)
Positive reviews82.4% of reviews — better72.7% of reviews
Number of ratings113 — better94
Update frequencyEvery 5 weeks — betterEvery 2 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.015.0 — better
Further details — not scored
Size1 MB43 MB
Age rating4+4+
DeveloperJohn HarringtonContechity AB

Customer experience

Libre Light Sensor

All ratings113 ratings
Positive94.7%
Neutral2.7%
Negative2.7%
Written reviews17 reviews
Positive82.4%
Neutral0.0%
Negative17.6%

Light Spectrometer Wavelength

All ratings94 ratings
Positive80.9%
Neutral3.2%
Negative16.0%
Written reviews33 reviews
Positive72.7%
Neutral3.0%
Negative24.2%

In-app purchases

None

Libre Light Sensor

No in-app purchases

4 purchases

Light Spectrometer Wavelength

Subscriptions3
  • Full Access7 Days trial$0.991 Month
  • Full access14 Days trial$0.991 Month
  • Full access$4.991 Year
One-time1
  • Full access4 variants$6.99

Questions

Is Libre Light Sensor free?
Libre Light Sensor 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, Libre Light Sensor or Light Spectrometer Wavelength?
Libre Light Sensor is rated higher. Libre Light Sensor averages 4.8 out of 5 from 113 ratings, while Light Spectrometer Wavelength averages 4.2 from 94 ratings.
Do Libre Light Sensor or Light Spectrometer Wavelength have ads?
Neither Libre Light Sensor nor Light Spectrometer Wavelength shows ads.
Which is updated more often, Libre Light Sensor or Light Spectrometer Wavelength?
Libre Light Sensor ships an update every 5 weeks, and Light Spectrometer Wavelength every 2 months. Most recently, Libre Light Sensor was updated on October 7, 2026 and Light Spectrometer Wavelength on October 9, 2026.

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