Got Dr.Meter from ebay, $28 including shipping with new hard plastic case.
So, fired it up, switched to FC and ran out side being bright hot clear day. 12,200 where average is 10,000 from web sites. Might check out some light bulbs before wife has me killed.
Any simple checks?
I plan to do a calibration of my luxmeter by using an incandescent bulb and a screen of Black matte cloth With a hole Cut out to pass light to the sensor.
The math is that a 60 W bulb with emission 850 lumen will have a light intensity of 850/4/PI = 67.6 Candela in all directions. If the sensor is held 1m from the bulb, the luxmeter should say 67.6 Lux.
But beware of false light from reflections from Walls etc.
You're missing a zero. Sunlight is about 100 thousand lux. Mine both measure in the mid 90 thousands. HS-1010 and CEM DT-1308.
Yes, sunlight IS about 100000 Lux and no, I am NOT missing a zero.
I was responding to Illuminaria.
i doubt you can calibrate a meter using the sun, the atmosphere is ever changing
Oh, I see, he must have overlooked a X10 switch position on his meter.
There is no easy way to check your meter. What people do is checking the lux with flashlights with known values, but even those can vary 5% or more, measuring multiple lights give bit better accuracy.
Best way is to have the meter calibrated, or have a (constant) lightsource measured. Both will be over 100 dollars, or dearer.
I was measuring foot candles. Lux, illumination by the meter right? I’m a yank!
I’m not sure I want to spend $100 on a $10 dollar meter, yipes! I was hoping to make a chart if I can get enough “known” cal sources.
Anyway, according to the web, I’m about 2200 FC high out the box.,should have got the $110 meter with cal certificate?