Casual flashlight evaluation

rotncore

Newly Enlightened
Joined
Feb 16, 2006
Messages
164
Location
Toronto
I'm grateful to those of you who take the time to graph runtimes and post screen shots and lux readings, but for my purposes, I think I've found my perfect way to check runtimes for my own lights at home. Best of all, I don't need to buy a light meter. I know it won't be as accurate as the graphs and charts, but I just want to know how long I can really have usable light for vs. manufacturer specs.

I use my webcam, and a free program called Dorgem, and have it take pictures at a 2 minute interval, or whatever interval (to the second) you want. The program can timestamp the files, and a quick thumbnail viewing of the directory it saves to lets me find the last one with light.
 

parnass

Flashlight Enthusiast
Joined
Nov 11, 2005
Messages
2,576
Location
Illinois, USA
If your webcam has an AGC (automatic gain control) type circuit, it would distort the image results.
 

kramer5150

Flashaholic
Joined
Sep 6, 2005
Messages
6,328
Location
Palo Alto, CA
if the program auto-compensates for varying degrees of light (like 99% of the cams do) it will not be much use... even for a casual evaluation. If you can pre set it for a fixed exposure and f-stop you'll be in business. If it can do black and white that would be ideal, as it would eliminate the influence of color on perceived brightness.

With the wrong camera settings, you can erroneously present a streamlight nano-light as equal output to the E2DL (another non-CPF www reviewer did this recently).
 
Last edited:

gallagho

Enlightened
Joined
Sep 4, 2006
Messages
213
Location
West Kirby, UK
Hi Rotncore, You could also get some usful figures by using a freeware image analysis package (NIH Image is good) to plot the average intensity of each image.
 
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