Comparison

Theta 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

Theta

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
Read full description

Application displays data from Theta-Meter devices (Wi-Fi and Bluetooth 4.0BLE connection) which measures human body galvanic skin response. Skin conductance, also known as galvanic skin response (GSR), electrodermal response (EDR), psychogalvanic reflex (PGR), skin conductance response (SCR) or skin conductance level (SCL), is a method of measuring the electrical conductance of the skin.

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

Theta1 screens
Light Spectrometer Wavelength4 screens

Verdict

The call

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.

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. Theta asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard6 real differences · 4 level
Theta versus Light Spectrometer Wavelength: the parameters behind the verdict, then further details
ParameterThetaLight Spectrometer Wavelength
PriceFreeFree
Rating5.0 (1 ratings) — better4.2 (96 ratings)
Positive reviews100.0% of reviews — better70.6% of reviews
Number of ratings196 — better
Update frequencyMonthly — betterEvery 2 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPod, Mac — betteriPhone, iPad, iPod
Requires iOS11.0 — better15.0
Further details — not scored
Size13 MB43 MB
Age rating12+4+
DeveloperMikhail FedorovContechity AB

Customer experience

Theta

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Light Spectrometer Wavelength

All ratings94 ratings
Positive80.9%
Neutral3.2%
Negative16.0%
Written reviews34 reviews
Positive70.6%
Neutral2.9%
Negative26.5%

In-app purchases

None

Theta

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 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.

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