Is there an app for measuring lux and lumens?

[busseguy]

I was just wondering if there was an app for measuring Lux and also lumens?

I have a Fenix TK16 V2.0 that is supposed to be 3,000 lumens but it doesn't seem like it to me and I figured it would be nice to be able to measure it and any other flashlights I recieve.

 

[kerneldrop]

Don't bother chasing that rabbit down the hole.
To get accurate measurements you either need to be a scientist that lives for this stuff or buy a sphere that a scientist that lives for this stuff made for you. Even then you need a known similar light to use as the benchmark.

 

[idleprocess]

Lux meters are readily available on the like of the Zon and will almost certainly be more accurate than a phone app taking a best guess at what the camera + ambient light sensors are reporting. You would need to sample the beam geometry to approximate lumens and/or experiment with some of the many variants on the DIY integrating sphere.

 

[desert.snake]

The most accessible piece is a industrial light meter, can show lux. Or do you mean programs for smartphone?

This should have 3100 lumens for at least ~2 minutes until it drops to a high level.

 

[raggie33]

i found one i loved but i forget its nsme i loved it since it had a timeline so ya could check runtimes easly

 

[busseguy]

The most accessible piece is a industrial light meter, can show lux. Or do you mean programs for smartphone?

This should have 3100 lumens for at least ~2 minutes until it drops to a high level.
View attachment 21580

An app for a smartphone is what I meant.

 

[desert.snake]

An app for a smartphone is what I meant.

I understand, then I don't know, I don't use a smartphone.

 

[kerneldrop]

An app for a smartphone is what I meant.

At first glance one would think that you buy a $25 light meter off eBay and shine the TK16 beam right at it 1 foot away. And bam you get your Lumens and lux. But that is not the case. They don't work like that.

People go to extreme efforts to build a light sphere and then relentlessly improve it with version after version.

 

[dc38]

There is a slightly older app that a friend in the architectural lighting industry used to use for quick and dirty snapshots, i believe it was called "Light Meter".

As far as lumen estimation, you really just need a way to take a cross sectional sample of the beam of light, such as putting uniformly dissipative diffuser on the lights to capture total light projected, then calibrate a lux meter accordingly. No need for the integrating spheres and whatnot. I concieved this method a few years ago, and it has been pretty accurate (and very inexpensive) so far.

 

[dc38]

It's a pretty simple idea, since any light that could possibly come out of a flashlight would be caught and deflected/reflective within the diffuser before finally being transmitted through it, we could assume that ALL the light is being emitted through the diffuser minus the losses.

In that case, one would just need set up a lux meter at a certain distance from either the surface or the center of any concentric/uniformly dispersive diffuser, as long as the diffusers for different sized lights are the roughly the same transmittance i.e. 90%. The calibration would simply consist setting a baseline lux number reading of a light that is of KNOWN or CONFIRMED lumen rating, then adjusting the distance from diffuser surface to lux meter sensor until the lux reading is the value of the lumen rating of the control light, and that distance will be the constant distance at which you need to set the surface of whatever diffuser away from the lux sensor. See image for reference.

P.S. for the record, you could also use a milk jug to make diffuser material

 

[PhotonWrangler]

There are apps like Physics Toolbox and Phybox that can report "illuminance level," however this can vary wildly depending on the camera's sensors. They're ok for subjective measurements but that's about all. BTW these apps can measure a lot of interesting things; select altitude/ barometric pressure while taking a ride in an elevator.

 

[jon_slider]

I was just wondering if there was an app for measuring Lux and also lumens?

there is the Ceiling Bounce App

Or you could buy the Texas Ace Lumen Tube

 

[busseguy]

Thanks for the help everyone.