Output of my lights (Fenix P1D CE Q5, UF FMR1, Conqueror M-C1, UF 3x CREE)

[jenskh]

Hello,

In a post yesterday (Comparing Flashlights), I presented my method of measuring light output from flashlights.
Here is what I have measured from my newly purchased lights:

Two modes normal and full (Turbo)

I have also checked the calculated lumens with lux measurements of light bouncing from the ceiling. It corresponds reasonably well.

What do you think, do the numbers look reasonable?
If you have any questions, please ask.

Jens

 

[Gunner12]

The # for the P1D CE Q5 and the M-C1 seem a bit high.

Seems like an interesting way to measure output.

 

[jenskh]

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

 

[Gunner12]

Your results seem pretty accurate.

A bit is about 10%, but that is from my calculations and not really based on fact so your results are probably more accurate then my calculations(keep in mind that I don't have any of the 4 lights, so I shouldn't be commenting).

 

[jirik_cz]

In my opinion your results looks quite accurate. Keep up a good work