CelticCross74
Flashlight Enthusiast
Its about high time I finally got a lux meter. What is everyone using, where did you get them and for how much?
If you want to do run time graphs, you need to have an integrating sphere ($$) or some type of home made light box that will provide a constant medium. Then all your measurements will be relative to each other. After doing dozens of tests and comparing to the manufacturers stated lumens, I have an equation that converts lux to lumens that works pretty good for my setup.Is luxmeter useful without the integrating sphere?
If you want to do run time graphs, you need to have an integrating sphere ($$) or some type of home made light box that will provide a constant medium.
I guess I could just shine the light at the meter at constant distance. However, the light box does keep other ambient light sources out such as the room lights.........and when I got interested in this sort of stuff, Quickbeam and Selfbuilt were doing a lot of run time graphs and so I thought those guys were pretty good examples to follow.Not really, measuring lux works fine.
Only a spectroradiometer can replicate the photopic curve with high precision.
That is not correct, the precision depends on the filter, it has to match the eye. Any meter can have a good filter, but due to the cost of a good filter very few meters have a good one.
The first category to avoid is meters where you have to select light source (Incan., sunlight, fluorescent, etc.), that means they do not really have a filter, but the calibration is only valid to a few specific spectrum's.
One test is to shine a UV lamp on the sensor, it must not show brighter that it looks, i.e. like a flashlight in moonlight mode.