Cool Gadget: Lumu Light Meter

by Photo Life
Lumu Light Meter

Lumu Light Meter

Over the last decade, as digital cameras have improved their LCD displays consistently with each generation, I’ve seen one tool slowly start to disappear from photographers’ camera bags: the light meter. “Why would I need a meter? I can just check the back screen and see if I need to adjust my settings.” This is a constant refrain when I bring up the topic of light meters. There are huge advantages to reading incident light as opposed to reflected light, like set-up time and consistency, but I can’t deny that it’s a pain hauling around a device the size of a lens or even some mirrorless cameras. That’s why I found the Lumu light meter very interesting.

The Lumu is an insanely small light meter that clips into the headphone jack on iOS devices. This struck me as an inspired design for a few reasons. First, there’s no reason for you to carry a bulky light meter when the screen on your smartphone is vastly superior (especially in bright light) and you always have your phone with anyways. Second, I can’t count the number of times I’ve pulled a light meter out after not using it for a couple months, and the battery is dead. The Lumu draws its power from your smartphone, so you never have to worry about batteries. Also, since the Lumu uses apps on your phone, there will be regular software updates expanding what the Lumu can do. We’ve already seen an update adding a reflected light meter using your phone’s built-in camera.

The free Lumu apps are a huge part of the meter’s appeal. There are currently three available—for photo, video, and pinhole photography. These apps are extremely well-designed and intuitive, even if you have never used a light meter. There are even straightforward tutorials included, so you won’t have to dive into a manual. My one request would be for the features of all three programs to be rolled into one downloadable app. As someone who is constantly switching between recording stills and video, it would be great not to have switch between apps—or potentially forget to download one of them before a shoot, as I did!

The one major limitation of the Lumu is that it is limited to reading ambient light. This means that you’ll still need to bring a traditional light meter when working with strobes. While this isn’t shocking given the Lumu’s price, it does mean that serious strobe photographers may still want to hang onto their Sekonics.

 As far as delivering on the promised features, though, the Lumu really impressed me. Comparing the readings with the much more expensive Sekonic 478D, the two units were always within 1/5th of a stop apart. I also much preferred  the smartphone interface of the Lumu to the occasionally annoying touchscreen of the 478. I never ran into a communication error with my phone, and the Lumu software was always stable.  I was also impressed with the feel of the small case that’s included. You can clip it right onto your camera strap and not worry about losing the tiny little meter.

After spending some time with the Lumu, I think it could be a great addition to most any photographer’s kit. It is inexpensive, gives consistent results, and takes up no space in a bag. The only thing that could give me pause is the forthcoming Lumu Power, which will add a flash meter and colorimeter to the mix, but at double the price. However, if you’re a photographer looking to dip your toe into the world of light meters, check the Lumu out at or

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