GB: 1W 520nm diode information/giveaway

Now that 5W figure is one I did want to hear.

People rely on that brightness tool too much... it's accurate for low powers but eventually sheer power makes up for visibility coefficients or what have you

ARG said:

I don't have 3.5W of 445nm on hand, but 5W of 445nm is definitely brighter than 1.4W of 520nm.

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Thank you! I've long suspected those brightness calculators were severely lacking in accuracy(up to 50%) based on my own observations.

I'm honestly surprised to read that.

I've been going off the rule of 4x power = 2x brightness

ARG said:

Unfortunately I can't keep it actively cooled for that long, my cooling setup is inadequate for the 12W of heat it produces at that power.

I can test the diode in the daytime, but it's rainy and the cloud cover is making it dark, so I'll try again tomorrow

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Thanks!

How about measuring the divergence? Is yours just like the 9mm blue as well?

ARG said:

I don't have 3.5W of 445nm on hand, but 5W of 445nm is definitely brighter than 1.4W of 520nm.

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Even beam-wise at night?
I find that strange, even my 150-180mW 532nm is between 1.3W and 3W of blue to my eyes (beam wise).

Maybe the brightness ratio changes at higher powers... Real bummer, then

Atomicrox said:

Thanks!

How about measuring the divergence? Is yours just like the 9mm blue as well?



Even beam-wise at night?
I find that strange, even my 150-180mW 532nm is between 1.3W and 3W of blue to my eyes (beam wise).

Maybe the brightness ratio changes at higher powers... Real bummer, then

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Beam divergence .... ofcourse i can't measure it from this distance, but look identical

9mm 445nm 3W

520nm 1.4W

You have a very nice place to compare divergence One day you should take a shot of all your lasers there, together!

How about the daytime beam? I'm sure you've tried by now?

Atomicrox said:

You have a very nice place to compare divergence One day you should take a shot of all your lasers there, together!

How about the daytime beam? I'm sure you've tried by now?

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Daytime beam is almost impossible with allot of wind outside, so i used some smoke in this shot.



And inside without smoke.

Atomicrox said:

Thanks!
Even beam-wise at night?
I find that strange, even my 150-180mW 532nm is between 1.3W and 3W of blue to my eyes (beam wise).

Maybe the brightness ratio changes at higher powers... Real bummer, then

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I'd bet it's closer to 1.3 than 3W. The green 532 usually has a much tighter beam compared to a 445 with a G2, which can make it appear brighter. Nobody doubts that green is brighter than blue, it's just those calculators are very inaccurate. e.g 1w of 520 should be equal to 24w of 445 beam wise, according to calc. Nobody has tested that, but it's probably not accurate

Atomicrox said:

Even beam-wise at night?
I find that strange, even my 150-180mW 532nm is between 1.3W and 3W of blue to my eyes (beam wise).

Maybe the brightness ratio changes at higher powers... Real bummer, then

Click to expand...

Yeah, even at night.

Keep in mind brightness is very subjective though. Results may vary for you

Yeah, it's closer to 1.3W but even then. We all know the calculator (and CIE data) is inaccurate but I expected at the very least green to be 4x brighter than blue.

Thanks for the answers, guys. I'm still getting one of these eventually but it has lost some priority for me (unless I win the raffle, of course!).

I find it really strange that it seems everyone sees their 638nm beam brighter than the 445nm even at much lower powers. I have two 638nm, one running around 600mw and the other near 1w and neither of them look anywhere as bright as my 1.8w 445 beam, in fact the beams on both of my 638nm are not very visable at all. The blue completely obliterates them in visibility AFAIC. I've also got a couple "burner" blues doing around 3.1-3.4 watts each and the beams look about twice as bright as the 1.8w and I've heard it takes a four fold increase in power to perceive a doubling in brightness. In the end this is clearly dealing in the territory of subjectivism but I would think my experience would at least resemble a close approximation of what I am hearing on these threads. I am starting to wonder if there really are a few people (me) who are outliers from the curve and very sensitive to certain colors. I wish I could hook up with a few of you and bring my lasers with me to do some experimenting with this. I guess I could even ask a few friends of mine to give me their opinions on brightness with my collection.

I am so very close to just dropping $800 on one of DTR's diodes. It's too much to hear all of this talk and not be tempted to "just do it". If these were $400 I would have been one of the first to buy. My mind is playing tricks on me now "400, 800, what's the big difference". I'm so addicted to this stuff. Glad I never tried crack.....

Jmillerdoc said:

I am so very close to just dropping $800 on one of DTR's diodes. It's too much to hear all of this talk and not be tempted to "just do it". If these were $400 I would have been one of the first to buy. My mind is playing tricks on me now "400, 800, what's the big difference". I'm so addicted to this stuff. Glad I never tried crack.....

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Murphy's law tells me that if you buy a diode you'll get the diode from the GB

God i love this new diode =)

Nice mint green.


635nm 1W
520nm 1.4W
445nm 3W

ARG said:

Murphy's law tells me that if you buy a diode you'll get the diode from the GB

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So you're telling me to buy a diode now with the intent to return it once I win.

Sorry DTR. :beer:

Atomicrox said:

Yeah, it's closer to 1.3W but even then. We all know the calculator (and CIE data) is inaccurate but I expected at the very least green to be 4x brighter than blue.

Thanks for the answers, guys. I'm still getting one of these eventually but it has lost some priority for me (unless I win the raffle, of course!).

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I think I'm going to take the calculator down. It causes too much confusion and dissent.

It also occurred to me last night that a big source of error was likely allowing the use of the relative brightness multiplier to calculate an equivalent wattage in a different wavelength. IE, if I had stuck to simply allowing comparison of X nm light to Y nm light, at the same mW value, and then producing nothing other than a multiplier (ie, X nm is 4 times brighter than Y), then the accuracy would probably have been fine. It's when we take the "4 times brighter" figure and try to claim that 500 mW of X nm light will appear the same brightness as 2,000 mW of Y nm light, that it all falls apart. If our understanding is that doubling of power doesn't double brightness even within the same wavelength, then it's completely illogical to think that we can apply linear scaling across two wavelengths.

A calculator that simply provides a multiplier in terms of perceived brightness of two wavelengths at the same power output, should be accurate (assuming it still accounts for Raleigh scattering, and then also, ideally, providing some ability to compensate for beam density).

Anyway, my calculator never did the latter, and I don't have time to re-code it to do the former. So I've taken it offline. Hopefully someone else can come up with a more current / accurate / evolved solution.

madmacmo said:

Please, please reconsider doing so. Your calculator has proven to be a very well used and valuable scientific tool, as perception of color and brightness will always be debated as everyone is gifted with slight to significant differences in retinas, optical nerves and brains; all of which are subject to degradation over time and by excessive drug use. :can:

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After you posted, I edited my comments to add a bit more about my thinking on this note.