Mini Review: Lumu Power, One Light Meter to Rule Them All?

December 11, 2017

By Bob Rose

The Lumu Power is an accessory that transforms your iPhone, iPod or iPad into a professional color and light meter. After sliding this, under 2 ounce, $299 attachment into the Lightning connector on our iPhone, we could easily measure color temperature, illuminance, spot, ambient and flash exposure.

So the question is, how accurate is the Lumu Power?  The short answer: it’s actually quite good, but it all depends…

Born in Ljubljana, the heart of Slovenia, the original Lumu Light Meter started shipping almost four years ago. The original fit into the audio jack of an iPhone and only measured ambient exposure, so although it’s very similar in appearance to the Lumu Power, it shouldn’t be confused with it.

Using the Lumu Light Meter app as the interface on your iPhone or iPad together with the Lumu Power hardware, we found it offers a wide range of controls, and given its very familiar shape, it’s almost inconspicuous in use.


Under average light conditions the Lumu Power did a respectable job of tracking our reference $599 Sekonic L-858-U Light meter, but fell a bit short as light levels lowered.  Comparing actual specs (and price) that’s no surprise. Overall we found it very handy, especially considering that unlike other light readers, it has the benefit of a big bright Apple display and the bonus of haptic feedback which gives your hand a little “bump” to let you know when a setting has changed.

Switching modes is easy and the display also tells you whether you need to have the half dome or the flat diffuser side of the Lumu Power facing up for metering. There’s also a provision to conveniently record settings and enter notes directly into your smart device.

General light metering was good, although in our experience we’d suggest sticking to the incident measurements and only consider the spot to see relative comparisons between areas of the scene, not for spot metering exposure.

Switching to flash metering provides simple exposure info as well as flash duration and displays the percent of illumination the flash contributes to the total exposure so you can easily balance daylight and strobe.

A quite complete set of controls is found within the Cine/Video settings, and there is even an option to accommodate the slight response difference between film and digital sensors.  It’s clear a lot of thought has been put into this device (including the online updates that Lumu Labs makes).

Hey, we did say it’s a color meter too?  Not only does it measure a correlated color temperature, it will also tell you what color filters you need to balance a light source.  This is generally well accepted by videographers, and although most photographers don’t think of needing a color meter, when you can make all your lights match, that’s a big deal – one that even Photoshop has to struggle with.

We pulled out an old Minolta Color Meter IIIF (since replaced by the Kenko KDM-3100) and our reference $1,499 Sekonic C-700U Spectromaster.  All things considered, as long as you stick to continuous light sources (daylight and tungsten) the Lumu Power did a good job.  However when the spectrum changes and it gets lots of spikes (LED and fluorescent) that presents a little bit of a problem. Although not as accurate as the dedicated color meters in this situation, the Lumu Power still offered valid recommendations on filtration to bring multiple light sources closer to a uniform balance.

And for those geeks out there, a Chromaticity mode displays the light source within the CIE1931 color space, also providing X, Y and Z coordinates.


A lightweight and easy way to add sophisticated metering capabilities to your arsenal of equipment.  A bright and large display that’s much easier to read than most of the currently available light meters.


If you don’t already have a compatible iPhone or iPad, you’re out of business – or you have to make a serious financial commitment.  It doesn’t quite replace a dedicated light meter or a color meter in terms of accuracy and durability.


The Lumu Power is a respectable and relatively inexpensive way to take better control of your exposure and the color of your lights.

Price: $299