Light Meter LM-30004.4.6

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/

Version History Added support for iPhone 18 Pro and Pro Max. 4.4.6 Oct 1 This update makes the LM-3000 more resilient when working with the iOS camera. 4.4.5 Aug 25 This update improves the LM-3000’s performance and stability. 4.4.4 Jul 24 This update enhances the usability by:
- Improving measurement rounding
- Fixing the HOLD button's touch area and its interaction with the diffuser warning
- Fixing a bug where the camera kept running while the measurement was not visible 4.4.3 Jun 30 Added support for iPhone 17e and the latest iPad Pro M5 and iPad Air M4. 4.4.2 Apr 2 This update adds support for Japanese, expanding availability to more users. It also resolves an issue that caused the accessory crosshair placement to appear misaligned on the iPhone 12 mini. 4.4.1 Feb 8 This update makes the LM-3000 even more powerful: it adds CCT measurements in Kelvin and beep sounds to the HOLD button for better control. 4.4.0 12/18/2025 This version introduces a brand new light source selection feature that allows you to choose the light source for maximum measurement accuracy. In addition, it offers improved performance in low light environments, a smoother calibration experience and other minor fixes. 4.3.0 12/04/2025 This update adds a new notification-style tooltip feature and fixes crashes that occurred when a subscription expired, as well as rare crashes while navigating the user manual. 4.2.2 11/19/2025 This update includes bug fixes and performance improvements to make your experience with the LM-3000 even better. 4.2.1 11/02/2025 This update brings major improvements to the LM-3000's user manual, making it easier than ever to use. It also adds new purchase options so you can choose what works best for you. 4.2.0 10/25/2025 This update includes default calibrations for the iPhone 17, 17 Pro, 17 Pro Max and Air – ensuring top level accuracy on Apple’s latest flagship devices. It also fixes issues related to the new front camera sensor that is built into the iPhone 17 series. 4.1.0 09/24/2025 Fixes crashes when resuming the app before having completed the tutorial. 4.0.2 08/27/2025 This update fixes rare crashes that can happen when bringing the app back to the foreground. 4.0.1 08/27/2025 We're thrilled to announce the release of the LM-3000 version 4, bringing a major leap forward in smartphone-based light measurement technology.

This update introduces our most advanced light measurement algorithm, thanks to RAW camera image-based processing. In addition, it dramatically improves low-light sensitivity for precise dark monitoring — a truly professional tool, accessible to anyone! 4.0.0 08/21/2025 This update separates the User Manual and Settings into distinct views for easier navigation. Furthermore, it adds Chinese language support. 1.10.0 07/08/2025 This update improves the diffuser accessory placement help and includes many minor bugfixes and stability improvements. 1.9.5 04/17/2025 This update fixes display issues when having Display Zoom enabled. Furthermore, it includes a few minor tweaks and performance enhancements. 1.9.4 11/20/2024 We've added a new feature that allows for an accurate placement of the diffuser accessory. 1.9.3 09/20/2024 We've added factory calibrations for the latest iPhone 15, 15 Plus, 15 Pro, and 15 Pro Max to ensure you get the highest accuracy available on any smartphone out there. 1.9.2 10/14/2023 This update adds small improvements to our user manual. 1.9.1 09/11/2023 After many years of development, an even higher level of measurement accuracy has arrived! We now offer our dedicated Lightray Diffuser accessory attachment to turn your device into a truly professional light meter. Learn more right within the app. 1.9.0 09/03/2023 We've updated our user manual to contain more information on how to use the LM-3000 app correctly. 1.8.0 12/26/2022 The new iPhones are here! We now added factory calibrations for the iPhone 14, iPhone 14 Plus, iPhone 14 Pro, and the iPhone 14 Pro Max. 1.7.2 10/07/2022 We've prolonged the length of our free trial so that you'll have at least two days to fully test the LM-3000. Furthermore, we've added many small improvements and invisible maintenance. We recommend the update to everyone. 1.7.1 09/10/2022