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Turn your smartphone into an incident light meter with Luxi For All.

Luxi For All is a small attachment for smartphones and tablets which works with a FREE app to turn your device into an incident light meter. When paired with the FREE Luxi™ app, Luxi For All will help you determine the best settings for your DSLR or other camera, so you can take perfectly exposed pictures.

What is Luxi For All?

Luxi For All is a diffusion dome attachment for your mobile device's front-facing camera. When paired with the Luxi app (availble both for iOS and Android), Luxi For All will help you determine the best settings for your DSLR or other camera, so you can take perfectly exposed pictures. It's just like one of those fancy old-school light meters, but at a far better price. And because it works with the gadget you already have in your pocket, it's way more convenient!

Luxi For All on an iPod Touch with a caseLuxi For All on an iPod Touch with a case

Why do I need it?

"I already have a light meter built into my camera; why do I need a separate device?"

The light meter built into cameras measures reflected light. A reflected light meter shows an appropriate setting for an average of the whole scene. If you are taking a picture of a scene that does has neither an average, nor internally consistent lighting situation, your camera's built-in light meter will not be accurate. Usually, that causes an overexposed or underexposed picture.

Types of light meters include: reflective and incident.

Sunset portraits and other pictures with strong back-lighting are common situations, and can be aided by using an incident light meter like Luxi For All.

A comparison between methods of light metering. Photo credit: PhotojojoPhoto credit: Photojojo

Will it work with my device?

Luxi For All builds upon the design of the original Luxi to bring convenient, inexpensive light metering to everybody who owns a mobile device. While the original Luxi was designed specifically for iPhone, Luxi For All will fit onto almost any of your gadgets with front-facing cameras: Android phones and tablets, iPhone, iPod Touch, iPad...you name it. Even if your device is inside a case!

Luxi for All fits on any device!Luxi for All fits on any device!

Luxi for All on an iPad MiniLuxi for All on an iPad Mini

Smart Cover? No problem.Smart Cover? No problem.

Reviews & Press Coverage

Well done, interesting and simple design. 

— Dr. Vlad Vyshemirsky, Developer of the Pocket Light Meter app

I love the idea. 

— Mark Meyers, Professional movie camera operator/ steadicam operator. Credits include: Mission Impossible III , Pirates of the Caribbean. IMDB

Professional photography on your keychain

David Weber, Professional Photographer

Reviews

Technical Information

In both our initial testing of Luxi For All and in nearly a year of experience with the original Luxi attachment, we have found the readings provided by iPhone apps paired with our devices to be highly comparable to readings taken with those old-school purpose-built light meters. The following picture shows a Luxi For All side-by-side with a relatively low-end Minolta Auto Meter IV F handheld light meter under even lighting conditions.

Light reading results of Luxi For All (L) and Minolta Auto Meter IV F (R) for price/performance comparison.Light reading results of Luxi For All (L) and Minolta Auto Meter IV F (R) for price/performance comparison.

Professional videographer / cinematographer Adam Wilt's really thorough examination of our original Luxi demonstrates just how accurate our device's readings are.

Other Compatible Apps

Below is a current list of software applications which are compatible with our Luxi hardware. Some of these apps address the specialized needs of niche interests and professions, so we've also attempted here to provide some help in deciding which app(s) is/are right for you and your preferred usage.

Applications for iOS:
  • Luxi is the official app developed by ESD for iPhone, iPod Touch and iPad. Its feature set is appropriate for the great majority of users, and is the recommended starting point. Users with advanced and/or domain-specific needs may want to look at one of the other applications listed below.
  • Pocket Light Meter is a third-party app which has many of the same features as our Luxi app, but also adds a few advanced features--such as footcandle readings--which might be useful to lighting designers, scientists, and the like.
  • Cine Meter II, also developed by a third party, is the app you're looking for if you're a videographer or DP. It is designed specifically for cinematography, and has many very useful features for that usage: shutter-prioritization, neutral density settings, a waveform monitor...and now, color metering! (note: color metering feature requires iOS 8.0 or greater)
Applications for Android:
  • Luxi is the official app developed by ESD for Android smartphones and tablets. This is a brand-new app, suitable for the needs of most amateur and professional photographers.

 

Frequently Asked Questions

What is Luxi?

Luxi is a small attachment for smartphones and tablets which works with an app to turn your device into an incident light meter. This type of light meter measures the amount of light striking a photographic subject, rather than simply measuring the subject's brightness (which is called "spot metering," and it's how the meter in your camera works). Photos taken with settings suggested by a light meter are often much more pleasing to the eye than photos taken with a simple spot meter.

What can Luxi be used for?

Beyond its primary use as an incident light meter for use in photography, Luxi can be used with special apps by third-party developers to measure light in other ways. For example, when paired with an app called Cine Meter II, Luxi can be used to measure the color temperature of a given light source. With other apps, Luxi can be used to measure a room's lighting conditions in LUX or footcandle units. See our list of compatible third party apps for more information.

My light meter app already has an incident mode. Why would I need Luxi For All?

It is important to capture all of the light falling on your subject. Luxi For All is designed to work just like a professional incident light meter which can capture light from a 180° angle. When using a light meter app without Luxi For All, the iPhone camera only receives light from a limited angle which means it doesn't capture all the light. This will produce readings that are both inconsistent and inaccurate. The Luxi For All effectively captures and averages all the incident light.

Will Luxi work with my smartphone’s case?

The original models of Luxi (the ones designed for iPhones 4/4S and 5/5s) will not work with cases; the newer Luxi For All will work with any case which is less than half an inch in thickness at the point where the phone's front-facing camera is located.

Which apps work with Luxi?

Luxi works with any light meter app that can use the front-facing camera and can be calibrated with an offset. We have tested Luxi with many of the light meter apps available for the iPhone, and we provide our own solution for Android. Please see our list of compatible applications.

Does Luxi work with flashes?

Unfortunately not. While Luxi itself has no limitations on this, light meter apps are unable to detect light coming from flashes due to smartphone / tablet hardware limitations.

Which smartphones / tablets are Luxi compatible with?

Our original versions are compatible with iPhones 4/4S and 5/5s. Luxi For All will work with any iOS device which has a front-facing camera, including iPhones 5/5s/5c, both iPhones 6, all iPads except for the first-generation model, and all iPods Touch with a front-facing camera. It is also compatible with the vast majority of Android devices, though there are some exceptions due to the huge number of different hardware configurations available. If in doubt, feel free to email us.

Will there be a Luxi for Android phones?

Yes; see Luxi For All.

Is it possible to measure general light levels with Luxi?

Yes, it's possible with apps which include this feature. However, we recommend using Luxi for reference purposes only.

Why do I have to calibrate the app?

We designed Luxi to be as accurate as possible. However, due to variances in the camera hardware from one phone to the next, some form of calibration must be done by the customer in order to ensure optimal accuracy. The good news is that this step should really only need to be taken once.

How do I calibrate the app?

The specific steps required for calibration depend upon which application you’re using, but the basics are pretty much the same across light meter apps. Our own Luxi app can be calibrated by completing the process below.

  1. Grab an 18 percent grey card (if you don't have one, they are available from any photography store, or on Amazon);
  2. Set your camera to aperture exposure mode, and choose spot metering;
  3. Set an ISO setting and an aperture setting and make sure that exposure compensation is set to zero;
  4. Zoom in on the grey card and make note of the shutter speed that the camera recommends;
  5. Compare this to what the light meter app suggests (with the Luxi-equipped iPhone sitting beside the 18 percent grey card in the same light) and use the calibration routine to fine-tune the app so that the shutter suggestion matches your camera's readings.

There may be a brief period of trial and error while you make calibration refinements, but before very long at all your calibration will be set and you won’t have to bother with it any longer.