Comparison

Light Meter LM vs Pace Clock

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

Head to head
About

Light Meter LM

Transform your smartphone into a professional light meter. Measure illuminance and color temperature with scientifically validated accuracy, trusted by professionals. Requires a simple diffuser for precise readings.

Highlights
  • Measure illuminance (lux/foot-candle)
  • Measure color temperature (Kelvin)
  • Industry-leading accuracy
  • Pre-calibrated for your device
  • Low light sensitivity
  • Save peak reading
  • Custom calibration option
Read full description

Turn your smartphone into a professional-grade light meter. Measure illuminance (lux/foot-candle) and color temperature (CCT in Kelvin) with unmatched accuracy — trusted by photographers, engineers, and lighting professionals worldwide. Why waste money on a hardware meter when you’re already carrying one in your pocket? The LM-3000 offers the same quality and usability as a traditional hardware light meter. Developed by optics scientists at the Zurich University of Applied Sciences, LM-3000 is the only light meter app scientifically validated for accuracy. It achieves professional-grade precision by leveraging your iPhone's front-facing camera sensor with advanced RAW image processing. Unlike relying on estimates like other apps, it adheres to the ISO/CIE 19476 standard, ensuring measurements you can trust for critical applications. MEASUREMENTS ⎷ Illuminance in lux or foot-candles ⎷ Correlated color temperature in kelvin FEATURES ⎷ Industry-leading accuracy, matching professional high-end lux meters ⎷ Pre-calibrated for your specific device ⎷ Excellent low light sensitivity to detect light pollution ⎷ No ads ⎷ No Bluetooth and location permission required ⎷ In-app manual ⎷ Save peak reading ⎷ HOLD function with acoustic signal ⎷ Custom calibration option to align readings to another meter DIFFUSER REQUIRED Like every real light meter, the LM-3000 requires a diffuser to measure accurately. A diffuser scatters incoming light evenly on the sensor and prevents hotspots. While it may sound complex, the solution is surprisingly easy. You have two options: 1) Easily build a diffuser yourself in less than a minute using standard printer paper. This is accurate enough for most use cases. 2) Get the dedicated Diffuser Accessory (free worldwide shipping) for best accuracy and convenience. More details on https://lightray.io/diffuser/ (!) Avoid apps that don’t require a diffuser! They are inaccurate because they ignore the basic physics of light measurement. TRY BEFORE YOU BUY The LM-3000 is free to download and comes with a free trial period. The trial period lasts for two non-consecutive days, giving you enough time to see if the app fits your needs. The status of your free trial will be shown as the "battery level" on the top right of the LM-3000's display and on the "Battery Status" screen. Once your light meter's "battery" is depleted, you may choose a Charging Option to keep using the app. You can pick what works best for you: → Single Charge — top-up for another 48 hours (perfect for occasional use), → Continuous Charging — a monthly subscription (great if you use it regularly), → Unlimited Battery — a one-time purchase for unlimited lifetime access LM-3000 is the result of over five years of dedicated research and development, ensuring you get a tool that is precise and reliable. Every in-app purchase supports future development and helps keep the app ad-free for everyone. As a member of 1% for the Planet, we donate at least one percent of all revenue to environmental non-profits — this is our way of giving back. ACCURACY Accuracy is not an afterthought — Apps developed by Lightray Innovation are developed according to the ISO/CIE 19476 standard. Thanks to RAW image processing and a default calibration per device model they’re able to match the performance of high quality traditional hardware light meters. To ensure quality we rigorously test our apps regularly on upcoming devices. DOWNLOAD FOR FREE. TRUSTED BY MILLIONS. LM-3000 is the go-to light meter for photographers, professionals, engineers, and lighting enthusiasts who rely on accurate measurements — not estimates or guesswork. Download for free today and experience the difference! See the app in action: https://youtu.be/EJW7NfE2qCk Terms and Conditions: https://lightray.io/lightmeter/terms/

About

Pace Clock

This versatile utility app helps you accurately time various activities, from workouts and study sessions to meditation and swimming. Its user-friendly interface and customizable settings make it easy to stay on track and achieve your goals across multiple disciplines.

Highlights
  • Accurate timing for any activity
  • Focus enhancement for study
  • Routine tracking for exercise
  • Versatile for multiple disciplines
  • User-friendly interface
  • Customizable settings
Features
Read full description

Introducing Pace Clock, your all-in-one companion for a myriad of activities! Whether you're into timing, swimming, training, study, yoga, meditation, exercise, or running, this app is designed to elevate your experience. Timing: Accurately track time for any activity, ensuring you stay on schedule and meet your goals. Focus: Enhance your study sessions by using the pace clock to manage your study intervals effectively. Boost productivity and concentration. Exercise: Whether it's a home workout, a morning run or other activity, Pace Clock ensures you stay on track with your routines. Set the pace, beat your records, and achieve your fitness goals. Why Choose Pace Clock? Versatility: One app for multiple activities, eliminating the need for separate timers or clocks. User-Friendly Interface: Intuitive design for easy navigation, making it accessible for users of all levels. Customization: Tailor the app to your preferences with customizable settings for each activity. Download Pace Clock now and redefine your approach to timing, swimming, training, study, yoga, meditation, exercise, and running. Your journey to optimized performance starts here!

Screenshots

Light Meter LM4 screens
Pace Clock4 screens

Verdict

The call

The clearest difference is review sentiment: Pace Clock at 100% against Light Meter LM's 40%. Pace Clock also leads on device support (5 vs 3). Light Meter LM's advantage is rating (4.5 vs 4.0) and ratings volume (2.6K vs 1). On price, update cadence, ads and in-app purchases 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 Meter LM sells 3 in-app purchases, starting at $3.49 per month and Pace Clock sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Light Meter LM holds the better App Store score, 4.5 against 4.0. That said, the two scores are not equally well evidenced: Light Meter LM has 2.6K ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 40% of Light Meter LM's written reviews are positive against 100% of Pace Clock's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Light Meter LM ships an update monthly, Pace Clock every 3 weeks. The most recent releases landed on October 15, 2026 and October 3, 2026 respectively.

Scorecard5 real differences · 5 level
Light Meter LM versus Pace Clock: the parameters behind the verdict, then further details
ParameterLight Meter LMPace Clock
PriceFreeFree
Rating4.5 (2.6K ratings) — better4.0 (1 ratings)
Positive reviews40.3% of reviews100.0% of reviews — better
Number of ratings2.6K — better1
Update frequencyMonthlyEvery 3 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, Mac, Apple Watch, Vision Pro — better
Requires iOS15.0 — better17.6
Further details — not scored
Size22 MB4 MB
Age rating4+4+
DeveloperLightray Innovation GmbHJason Fleischer

Customer experience

Light Meter LM

All ratings2,583 ratings
Positive88.0%
Neutral3.7%
Negative8.4%
Written reviews206 reviews
Positive40.3%
Neutral5.8%
Negative53.9%

Pace Clock

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

Light Meter LM

Reported bugs

3 issues
  • Diffuser not recognized even when used
  • App locks up/crashes
  • Constant diffuser pop-up interruptions

Requested features

3 requests
  • Ability to use rear camera
  • More flexible diffuser options
  • Improved accuracy without diffuser

Pace Clock

Not enough reviews yet to summarise bugs or requests.

In-app purchases

3 purchases

Light Meter LM

Subscriptions1
  • Continuous Charging$3.491 Month
One-time2
  • Single Charge$0.99
  • Unlimited Battery$19.99
1 purchases

Pace Clock

One-time1
  • Fully Unlocked$1.99

Questions

Is Light Meter LM free?
Light Meter LM is free to download, with in-app purchases available.
Is Pace Clock free?
Pace Clock is free to download, with in-app purchases available.
Which has better reviews, Light Meter LM or Pace Clock?
Light Meter LM is rated higher. Light Meter LM averages 4.5 out of 5 from 2.6K ratings, while Pace Clock averages 4.0 from 1 ratings.
Do Light Meter LM or Pace Clock have ads?
Neither Light Meter LM nor Pace Clock shows ads.
Which is updated more often, Light Meter LM or Pace Clock?
Light Meter LM ships an update monthly, and Pace Clock every 3 weeks. Most recently, Light Meter LM was updated on October 15, 2026 and Pace Clock on October 3, 2026.

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