Thank you for commenting. I am working on the method now, and therefore very eager to find out if the results are realistic or not. I have tried several other more manual methods to multiply measured lux with area and add together, and they all seems to indicate that I am doing this right. I also have one verification on the M-C1 light where I have measured the output in lux in 1 m and 2 m distance from the light. When calculating the lumens (shown in the graph) I end up with very close numbers as should be.
I have also as mentioned directed the lights towards a white ceiling, and measured the reflected light at a point about 2 m from the ceiling. The reading in lux is very little sensitive to the location of the light itself. Here are the readings (in lux):
Fenix P1D CE Q5: 11
Ultrafire FMR1 Rebel: 7
Conqueror M-C1: 11
Ultrafire 3xCREE: 25
If we divide the calculated lumens by these numbers, we get: 14.6, 16,8, 16,4 15,3. This shows a reasonable consistency between my calculated lumens and the intensity of the reflected light.
One possibility is of cource that my lux meter is not correctly calibrated. I can control zero, bu appart from that, I have little reference. I have bougt a lux meter to verify my flashlights, what can I buy to verify the lux meter
?
By the way, this is the lux meter I have choosen:
http://cgi.ebay.com/ws/eBayISAPI.dl...item=160206410032&_trksid=p3984.cWON.m313.lVI
The # for the P1D CE Q5 and the M-C1 seem a bit high.
Do you have any indication on how much "a bit high" is?
Actually compared to the other lights I was surprised that the M-C1 light was not even higher in lumens. It has a wonderful spot that throws at least 100 m and it has a very good and even spill that in a comfortable way lights up the close surroundings. I realy like the output of that light.:twothumbs By the way, my son has ordered one too, so in a few days, I can check if it gives the same output as mine.
Regards rom
Jens