Casual flashlight evaluation

[rotncore]

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]

If your webcam has an AGC (automatic gain control) type circuit, it would distort the image results.

 

[kramer5150]

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).

 

[rotncore]

Dorgem lets you turn off gain control.

 

[gallagho]

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.