You guys are pretty picky about beam quality, so I thought you might appreciate this.
Messing with a beamshot of my Surefire A2, I found a basic but relatively easy way to get a feel for just how the beam's brightness is distributed -- lumpy, bumpy, misshapen, or what.
I started by opening the beamshot image in some image editing software. I use GIMP ( www.gimp.org ) because I use the Linux operating system, but you can use others equally well.
Next you navigate through the editing features and find where you can use "threshold" adjustment. This makes a white and black image where everything is black except for pixels that are within a range of brightness you specify. The full range is 0-255. Below is the threshold dialog box for GIMP and the image with everything from 127 to 255 white. . .
and the image. . .
You can also check what lies from, say, 84 to 87:
Not real scientific, but it does "illuminate" beam quality pretty well.
Please note that this particular beamshot was taken at an oblique angle with a wide-angle lens, so there is a fair amount of geometric distortion present. The non-circular pattern does not imply a non-circular beam. You would need to take a straighter shot to do a valuable comparison.
Scott
Messing with a beamshot of my Surefire A2, I found a basic but relatively easy way to get a feel for just how the beam's brightness is distributed -- lumpy, bumpy, misshapen, or what.
I started by opening the beamshot image in some image editing software. I use GIMP ( www.gimp.org ) because I use the Linux operating system, but you can use others equally well.
Next you navigate through the editing features and find where you can use "threshold" adjustment. This makes a white and black image where everything is black except for pixels that are within a range of brightness you specify. The full range is 0-255. Below is the threshold dialog box for GIMP and the image with everything from 127 to 255 white. . .
and the image. . .
You can also check what lies from, say, 84 to 87:
Not real scientific, but it does "illuminate" beam quality pretty well.
Please note that this particular beamshot was taken at an oblique angle with a wide-angle lens, so there is a fair amount of geometric distortion present. The non-circular pattern does not imply a non-circular beam. You would need to take a straighter shot to do a valuable comparison.
Scott
