Lumu Light Meter 4+

Pro color and flash meter

Lumu d.o.o.

    • 3.3 • 88 Ratings
    • Free
    • Offers In-App Purchases



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 3.3.6

Hey Lumunauts,
Thanks for using Lumu Light Meter!

This is just a quick update that fixes a crash when using the app on iOS 12.

As always, any feedback, suggestions or advice can be sent directly to

Ratings and Reviews

3.3 out of 5
88 Ratings

88 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.

blinddogbeach ,

2 stars for lack of support

I have nothing bad to say about the functionality of my Lumu Power 2. It gives me ballpark readings on outdoor ambient light on a daily basis for my job, shooting mostly landscape video. I mostly use it for color temperature, but after a recent app update I immediately lost functionality of my color meter. It will give me no readings and gives the error “cannot read CCT”. I tried a factory reset of the module through the app: it gives me an error and asks me to check my internet connection every time I try. I’ve tried chatting on iMessage through their website, DM on Instagram, and e-mail - I’ve received no response in well over a week. That’s just too long for me to receive no reply from multiple communication mediums and multiple follow-ups. I want to use this module and want to make it work (and will continue to) if they ever get back to me. If you’re looking for a product that does what it says and you’re not concerned with what to do if something goes wrong, then you’ll probably enjoy what it has to offer while it’s working.

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.

App Privacy

The developer, Lumu d.o.o., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Usage Data

Privacy practices may vary, for example, based on the features you use or your age. Learn More

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