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Looking for opinions about my laser brightness

LEDbeam

LEDbeam

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Joined
Feb 19, 2016
Messages
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I had a 1.5 watt blue laser about 6 years ago and it was my first high-powered laser. It only lasted for 9 days, so videos I made are all I have left of it.
I heard that green lasers are much brighter due to our eyes being more sensitive to that color. I just bought one of those and got it in the mail 3 days ago.

To compare, I tested the green laser in the same place and under the same conditions as I did the blue one 6 years ago. It was during the daytime, but it was an overcast day both times. I was surprised to find that the green laser (700mw) was not as bright, even though I've heard that a 700mw green is about the same brightness as a 4 watt blue. Since my previous laser was only 1.5 watt, I thought my new green one would be at least twice as bright. But it doesn't seem to be.

I made a video of the green laser and put it together with the blue laser video. Tell me what you think.
 





The videos are an unreliable/false comparison for a variety of reasons, more than likely, and not an accurate representation of anything but camera videos at different times under different conditions.

Do you imagine your camera and it's auto brightness correction is exactly the same in response to different wavelengths of light as your eyes human vision system and that atmospheric conditions and ambient light levels are the same 6 years later among the many other variables?

532nm is visually the brightest based upon normal eye retina sensitivity to wavelengths, not Raleigh scattering.
See relative brightness calculator and plug in the mW and wavelength values here: https://slickscreen.github.io/laser-tools/brightness/

At same output power in mW 532nm green is visually 8X brighter than 450nm blue and 16X brighter than 650nm red.
 
Did you measure the green to actually be 700mW? I have a 524nm @ 750mW that absolute smokes any of my 425nm-450nm blues that sit in the 1-2W range. Once the blues start getting up around 460-470nm they get pretty close thanks to the extra power.

Are you comparing brightness between the lasers based off of what is recorded on a video? If so you will never get an accurate representation.

Which one of these two lasers is producing over 4 times the power of the other one?
IMG-7262.jpg

The look pretty close don't they?

Also brightness doesnt scale linearly, a 4W laser will not look 4 times a bright as a 1W laser of the same wavelength
 
Last edited:
Gryphon said:
Are you comparing brightness between the lasers based off of what is recorded on a video? If so you will never get an accurate representation.
Click to expand...
Exactly, not a measure of anything but a camera response to a different laser 6 years later, under different conditions, and pretty much useless/meaningless except to show you have had a blue and have a green of whatever "green" wavelength and output power laser pointer.
 
Last edited:
Encap said:
Exactly, not a measure of anything but a camera response to a different laser 6 years later, under different conditions, and pretty much useless/meaningless except to show you have had a blue and have a green of whatever "green" wavelength and output power laser pointer.
Click to expand...
What you see in the video is the same as what I saw in real life.
 
Gryphon said:
Did you measure the green to actually be 700mW? I have a 524nm @ 750mW that absolute smokes any of my 425nm-450nm blues that sit in the 1-2W range. Once the blues start getting up around 460-470nm they get pretty close thanks to the extra power.

Are you comparing brightness between the lasers based off of what is recorded on a video? If so you will never get an accurate representation.

Which one of these two lasers is producing over 4 times the power of the other one?
IMG-7262.jpg

The look pretty close don't they?

Also brightness doesnt scale linearly, a 4W laser will not look 4 times a bright as a 1W laser of the same wavelength
Click to expand...
I don't have a way of measuring the actual power output. I'm just going by the manufacterer's claim.
 
700 mW in a tight beam should burn wood. Maybe a brown paper bag as well. It isn't as good as measuring it, but might give you something to go on.
 
paul1598419 said:
Should be close then. To know exactly, you'd have to measure it or get someone else to measure it for you.
Click to expand...
I'm thinking it's probably what it was advertised to be. I'm just kind of disappointed that it wasn't like 2.5 times as bright as the blue one I used to have. It's still blindingly bright when it hits something, such as a tree trunk in the distance. A tree trunk is dark, and should absorb a good amount of the light that hits it, but the laser dot on it is still rather uncomfortable to look at.
 
Do you know the humidity levels in your area? If it's dry maybe that's why the beam isn't so bright... I dunno
 
Temperature is your enemy here. The pump diode must be at least 3 or 4 watts. They have a low Vf, so not as much heat as say a 520nm diode, but still a lot for a pointer.
 
Unown (WILD) said:
Do you know the humidity levels in your area? If it's dry maybe that's why the beam isn't so bright... I dunno
Click to expand...
It varies a good amount.
I know that it was quite humid when I took the video of the blue laser. We just had rain. Not the case when I videoed the green one.
 
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