The light metering tool for every great image maker.

Use the standalone app as a reflective light meter or use it in combination with Lumu Power hardware for professional Flash and Color Temperature measurements.

Lumu Power is an easy-to-use digital incident color and light meter that works seamlessly with the free Lumu app to deliver Color Temperature, Illuminance, Spot, Ambient, and Flash Exposure metering functionality on your iPhone.
A new expression of what a light meter can be, Lumu meets the needs of enthusiasts, professionals, and students who find existing light metering solutions too bulky, expensive, and complicated.

“The Lumu Power is without any doubt the most full featured light meter I have ever owned. It’s tiny, it weighs hardly anything, it manages to offer a feature set that expands way beyond what most will ever need from such a device.” -

Key features:

- SPOT METERING: Use your phone’s camera as a reflective light meter.

With Lumu Power:

- PHOTO SINGLE mode: Giving you exact parameters: exposure time, f-number, ISO, EV, lux.
- PHOTO MULTI mode: Calculating average value or contrast between multiple measurements.
- PHOTO PINHOLE mode: Measuring exposure time for custom pinhole camera settings.
- CINE/VIDEO mode: Set FPS, F-number, exposure time and ISO. Get the values for the ambiental light.
- FLASH EXPOSURE: See the graph of flash duration, measure its intensity.
- COLOR TEMPERATURE: Read light Color temperature in Kelvin and Green/Magenta shift.
- CHROMATICITY: See light colour in CIE1931 diagram and get X,Y,Z coordinates.
- ILLUMINANCE mode: showing incident light level in lux / foot-candle values.
- NOTES: Store all your measurements together with geo-location, custom notes and your photo in one place.


Visit to learn more.

What’s New

Version 3.3.4

Hey Lumunauts,
Thanks for using Lumu Light Meter!

Here's what's new:
- Calculated parameters get updated when EV compensation changes
- EV compensation menu stays on the last used section
- Support for system-wide Dark Mode
- Minor bugfixes and improvements

We hope you enjoy this update, and if you run into any troubles or have a suggestion for the app, let us know at

Ratings and Reviews

3.5 out of 5
71 Ratings

71 Ratings

chrismartindp ,

Real convenient but not that accurate

Light meter that works with the phone I’ve got on set anyway…awesome but the color meter feature isn’t very accurate at all. The reflective meter is accurate to within a tenth of a stop of my Sekonic meter, so that’s great and better than I expected. The spectrometer does a great job too. Where is falls short is in the color mode. Honestly the main reason I bought it. Small pocket sized tool that gives reflective metering and color. The accuracy is really really off though. Measuring outside in direct sunlight measures ~4300 kelvin…a true tungsten bulb measured about the same. Re-measuring an led source produces wildly different measurements every single time under the same conditions. Compared to my Sekonic C700 is laughable. Not that I expected this to be the same but this function (the reason I chose the pro version of the product) is so unusablely wrong that I don’t ever ever use it or would ever trust it.

Heath Shelton ,

Not as good as I thought

Just received my lumu power and it does not read flash as good as my 21 yr old sekonic. I have to be right next to the flash before it will read. I can not stand where I put my subject and read the flash like I do with my sekonic. I was excited to get because I would not have to carry an extra device around but I’m gonna still have to.

Developer Response ,

Sorry to hear that. Every Lumu is built to measure as accurate (or better) as other products but sometimes it depends on the tests, so we would really appreciate if you could contact us via iMessage support on our website so we can see investigate on potential issue. With Lumulove.

Simple but fun fun fun!! ,

Overall excellent

The app plus the lumu sphere attachment is pretty good and could be great with some added features and tweaks. I was using it on a shoot today shooting 120 film and wanted to shoot on F/1.4 and wanted my exposure to be based off that criteria but the app only has shutter priority and ISO prioty; meaning it’ll lock down the shutter speed and ISO setting and only the F-stop changes. It would be nice to lock down the F-stop and let the shutter adjust to the selected criterias. This is a standard feature and should most definitely be available for a standard meter.

The other feature just needs a little tweak is when the reading or setting is out of range way over or under there is a warning that comes up on the top of the screen but it’s not obviously enough.

App Privacy

The developer, Lumulabs d.o.o., has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

You May Also Like