Estimated Brightness?

[wolfhunter9154]

So a few weeks ago I ordered one of those ebay "5 mW" 405's knowing that it would be overpowered, but what I got is more than I expected. I dont have a LPM, but how many mw's do you think it is if I can see the beam in my room with the lights on? It would have to be at least 100+mW right?

 

[DJNY]

Make a vid lightning a match and I may be able to help you a bit with a roughly power estimation.

 

[Ablaze]

Yes, based on that description it sounds like it would be 80-150mw.

 

[wolfhunter9154]

I cant focus it, but ill try it and record it. I'm guessing you would use the video for the time it took to light correct?

 

[Fiddy]

how big is the dot up close?

 

[wolfhunter9154]

It is about the size of the match head, which I was unable to light.

 

[Sigurthr]

100mW with a beam diameter of 4mm^2 is not really enough density to light a match. Your problem isn't power, just power density. Try adding a magnifing glass.

Regarding the visibility, it probably is overspec because the dot from 5mW 405nm isn't very visible at all, heh. I had a 10mW'er and you couldn't see the beam in pitch darkness.

 

[wolfhunter9154]

Yeah, I figured that. I was just wondering what power it would be around.

 

[Sigurthr]

In before Jerry;

"The only way to determine the power of a laser is with a calibrated LPM", hehe.

 

[Fretwrecker94]

Yeah, I figured that. I was just wondering what power it would be around.

I got one pretty overspec a while back. Mine LPM'd at around 70mW + 5% since its a DIY LPM

 

[joeyss]

Try it on your hand skin...if it even feels slightly warm it'll be able to burn when focused to a tiny dot. Mine is one of those 40-50mw ebay pens and it can even light a white match if i used a lens that focuses it about half a inch from the match. Also that's nothing....500mw of blu-ray focused to point.....will eat anything non metal that isn't clear in a very short time...almost too short to measure.