Light meter app for phone?

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sw_ross

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Anyone use an app for your phone that measures the light level (lumens?, or foot-candle?)?

I want to retro fit a garage bay that has fluorescent fixtures with LED's, and just want to get a baseline to make sure I get fixtures with comparable light output.

Also, LED fixtures have a lumen rating but I don't see a lumen rating on fluorescent fixtures? Any reason?

Thanks!
 
sw_ross said:
Anyone use an app for your phone that measures the light level (lumens?, or foot-candle?)?

I want to retro fit a garage bay that has fluorescent fixtures with LED's, and just want to get a baseline to make sure I get fixtures with comparable light output.

Also, LED fixtures have a lumen rating but I don't see a lumen rating on fluorescent fixtures? Any reason?

Thanks!
Click to expand...

See here. The short answer is, not a good idea.
 
480sparky said:
To confuse you. Besides, lumens are not something you can just measure with a meter.
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Correct. Lux is a unit of illumination of a surface at a location, from any combination of light sources. It determines how well lighted any object placed at that position will be.
It can be measured by a simple light meter, the kind that used to be used in photography.
It is the unit used to describe low light sensitivity of a camera. The lower the minimum lux level for a decent picture the better the camera will perform in low light conditions.

Lumens relate to the total amount of luminous power (energy per unit time) emitted by a source. To measure it properly you need to be able to collect all of the light emitted by the source in all directions. For formal measurements this requires placing the source inside what is called an integrating sphere, which produces a meter reading proportional to the total light hitting the entire inside surface of the sphere.

A 1 lumen source which produces a narrow beam will provide more lux at a given position at a specified distance (and direction) from the source than a 1 lumen source that produces a wide beam or omnidirectional light (like a type A incandescent.)
But for some purposes the light from a wide beamed source is much more useful.

The foot-candle (the intensity of luminous flux at a distance of one foot from an omnidirectional reference source called a standard candle) measures the same thing as the lux, I believe.
 
sw_ross said:
Anyone use an app for your phone that measures the light level (lumens?, or foot-candle?)?

I want to retro fit a garage bay that has fluorescent fixtures with LED's, and just want to get a baseline to make sure I get fixtures with comparable light output.

Also, LED fixtures have a lumen rating but I don't see a lumen rating on fluorescent fixtures? Any reason?

Thanks!
Click to expand...

I've tried a few different light meters on two different phones (one android, one IPhone), and neither worked very well. In almost all cases the reading would jump between very different levels. For example, maybe go from 60 FC to 150 FC and never get a reading in between, even as I was slowly moving a dimmer switch.

Fluorescent fixtures don't have a lumen rating because they aren't sold with the lamps. The lumen output depends on what lamps are installed in the fixture. Sometimes you can find a "test" lumen output using a specific lamp.
 
sw_ross said:
Anyone use an app for your phone that measures the light level (lumens?, or foot-candle?)?

I want to retro fit a garage bay that has fluorescent fixtures with LED's, and just want to get a baseline to make sure I get fixtures with comparable light output.

Also, LED fixtures have a lumen rating but I don't see a lumen rating on fluorescent fixtures? Any reason?

Thanks!
Click to expand...

i downloaded this one, and will play with it tomorrow, and post results.

what i've got to compare it to is this, which most likely is about the best iphone
light meter there is. (app is free. bluetooth lightmeter/spectrum analyzer is $2k)

https://alliedscientificpro.com/shop/product/lighting-passport-smart-spectrometer-20827
 
or maybe just get a inexpensive DMM that has a legit light meter in the top of it.

smart phones alone will not work correctly.
 
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