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In the previous post “can an iPhone work as a calibrated microphone?“, it was shown the possibility of using an iPhone as a sound meter for noise measuring at work. In a line with that, we now show different possibilities to use this outstanding smartphone as a calibrated light meter.

Several apps exists allowing iPhone to work as a light meter using its built-in camera as a light sensor. I tested some apps, prioritising those allowing a calibration of the measured value in order to adjust it to real values and these are, in my opinion, the most highlighted ones:

iphone as a light meter - apps lux pan

After several tests, I found a common problem: values variability during getting samples, displaying unstable and unalike readings depending on how the camera received the light from the lamp or the focus point.

We must take into account that, as Whitegoods manual says, a light meter sensor measures the widest angle of light, but iPhone´s camera measurement range is hardly in one direction what, in addition to autofocus function, measures insolvent results, as shown in the images above.

As  happened when using the iPhone as a sound level meter, I was about to throw in the towel  when I met Luxi. It´s a little and cheap device (some 22€) consisting of a diffusion dome that fits over the iPhone´s camera. Originally designed for photography purposes, I tested it in order to check if previous deficiencies were solved.


Luxi improves the readings stability and and, depending of the installed app, more trustable values are measured. We must take into account that calibration in apps is not perfect since it is done adjusting a bar in the display with the finger. But, with some patience, settings may be adjusted according to calibrated range with a +-5% margin of error.

IMG_1926 IMG_1923megaman 

Among the 3 apps, Whitegoods was the one giving the most trustable and stable values, and I loved it for its simplicity.

Other option to use the iPhone as a light meter what seems to solve more proper to the iPhone´s camera restraint, is Lumu. It is a device with a built-in sensor and diffusion dome that plugs in the headphones jack and measures the light level directly, without the need to use the camera.


Lumu is about 95€ and is available both for iPhone and Android, is equipped with a high precision and wide measuring range sensor.

Find this video showing how it works and its precision.

Do you know any other gadgets which make easy our work as consultants?. We do. So, stay tuned to PrevenBlog!


PrevenControl es la firma especializada en seguridad y salud laboral que propone soluciones eficaces e innovadoras para la mejora del negocio y la reputación de sus clientes a través de la consultoría, el uso de la tecnología y la formación.

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    Hmm is anyone else experiencing problems with the images on this blog loading? I’m trying to find out if its a problem on my end or if it’s the blog. Any suggestions would be greatly appreciated.

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    I liked your post and I want to discuss about one very simple lux meter app for android that is “Roshni – Lux Meter” , this app is a very small size and simple light measuring app it shows light intensity in form of sound wave. If anyone wants to download this light measuring app (less than 5.5 mb) then they can download by clicking this link https://play.google.com/store/apps/details?id=com.gearedbrain.Roshni . This app shows light intensity in form of sound wave and also a circular bar and it is a very simple app.

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    I want to make sure you know of our recent update.

    Luxi For All is a simple, low-priced device that clips onto iPhones and works with FREE app to accurately read light intensity for photographers. For only $20 users can get a viable light meter.

    See our product-specific website at http://www.LuxiForAll.com for more information.