Luxi, The Little Light Meter For the iPhone


The little Luxi turns your iPhone’s front camera into a light meter. A what? A light meter, a device that measures the amount of light falling on a subject so that you can set the exposure correctly on your camera.

But wait, doesn’t you camera already set its own exposure? Doesn’t it have a light meter built in for when i want to kick it old school in manual mode? Yes and yes, but this $30 widget might still be handy.

In combo with a companion app, the Luxi is little more than a white translucent dome that covers your iPhone’s front camera, and tells you how much light is falling on it. This is translated in the app to tell you the exact settings you need to dial in on your camera.

The big difference is that the Luxi measures the light that’s falling on your subject, not the light that reflects from the entire scene in front of you. That’s becasue even the fanciest of cameras can be fooled.

Imagine you are snapping a picture of somebody. Their face in in deep shadow, but the scene behind them is lit up by the midday sun. Even the best camera may get confused, thinking that you’re snapping a photo of the whole scene and that your subject is maybe just some dumb rock in the foreground. So your friend’s face is plunged into black while the junk-littered street behind them is perfectly exposed.

Switch to the Luxi, or a $250 purpose-made incidence light meter and you put it in front of their face and point it back at the camera. This tells you how much light is falling on them. The background could be a black whole or a white dwarf and it wouldn’t make any difference (well, you might get sucked in or burned to smithereens I guess).

Or, in the case of digital, you can just chimp your shots until the exposure’s correct and go from there.

Whatever, this former Kickstarter is now available to buy from the Photojojo store.

Source: Photojojo

  • lucas

    I’m a lighting designer who owns one of those $250+ Konica Minolta light meters. I was also an early Kickstarter backer of the Luxi light meter and have received mine already and downloaded their app. When using both light meters side by side, the Luxi app is grossly inaccurate when compared to a professional/calibrated light meter. The app allows you to calibrate its measurements, however only with 0.1 intervals, which is not small enough to calibrate to accurate values.
    Maybe it’s a good device for photographers – but lighting designers beware. It’s worth investing in a real light meter instead of relying on the Luxi app at this point.

  • Extrasensory Devices

    Hi, Lucas. I’m Jarrod Whaley, the operations manager at Extrasensory Devices–we make Luxi. I’d like to try to address your concerns regarding the product.

    It’s probably true that our own Luxi app is better for photographers than for lighting designers; we decided to aim the product primarily at photographers because it’s a broader market, and so these early versions of our app are probably going to reflect that focus.

    What’s not widely known, however, is that there are third-party apps out there which support Luxi 100%, and which can provide functionality to suit almost any need a user might have. There are apps specifically for cinematographers, etc. In the case of lighting design, our current recommendation is an app called Pocket Light Meter (just search the iOS app store for it). Its calibration routine is a bit more fine-tuned than in our Luxi-branded app, and it also gives footcandle readings. For lighting design and / or scientific use cases, PLM is probably the best way to go right at this moment. Give it a try!

    Also, do feel free to contact us directly at We try to answer all emails from our customers, we’re friendly, and we try to do our best to help in any way we can.