Thanks for your words of appreciation.
I have too and ordinarily one might expect that I would mention that but I don't look to the wrongs of others to try and justify what could be viewed as a wrong committed by myself. :beer:
-Scott
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FrozenGate by Avery
Video: 1 Watt Pocket Blue Laser Beam from Eiffel Tower
- Thread starter Netscott
- Start date
I have too and ordinarily one might expect that I would mention that but I don't look to the wrongs of others to try and justify what could be viewed as a wrong committed by myself. :beer:
-Scott
I think the point being made here, is that while what you did was most likely not harmful, it still had the potential to damage someone else's vision either temporarily or permanently. It doesn't matter how small this chance is, it is unreasonable to force that on some random strangers without their knowledge. I believe that is the point being made. If you wanted to risk your own eyesight on your judgement of the variables no one would care, but you risked someone else's who was not aware of the potential dangers.
The point is that what you did was potentially dangerous, the people you put at risk did not know of the risks or how to best avoid them (ie not staring at the beam).
It is simply not reasonable to expect some random person to know the dangers of a laser and how to avoid getting damaged by one. If someone chose to stare directly at the laser beam because they thought it was cool looking and you permanently damaged their vision because they didn't look away, that would still be your fault.
You appear to have taken proper precautions and most likely didn't cause any problems, but it simply isn't acceptable for you to have risked other people in your experiment. It's kinda like me taking a rifle out in public and shooting rounds all around you. I have a scope so I can be accurate and miss you all of my shots, but I'm fairly certain you would be pretty upset with me either way. That's how most people here view lasers, they should be treated just like firearms because they can be nearly as dangerous (less likely to be leathal, but much easier to permanently maim someone). While my gun scenario would appear to have reasonable saftey precautions to prevent any damage from being done, it simply would not be considered acceptable for me to have put you at risk even though I'm fairly certain no harm would come to you.
Hopefully that makes more sense, I know it's not an exact comparison but it should help give you some idea how people here view what you did. Is it cool looking, sure. But it's probably not something I would have done, especially in the US where they most likely would have hauled me off to jail for something like that.
Benm
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I think he has though the risks through... sure it might be edgy, but its certainly not randomly doing something without considering safety first.
People may not be aware of the risks, but the blink reflex is exactly that: a reflex that is involuntary. Obviously someone could purposely stare into the beam, even holding their eyelid open with their fingers, but that would be a great deal of stupidity on their part. Most people stop doing something that hurts, and the only reaction required here is looking away or letting your eyes blink when they want to.
People may not be aware of the risks, but the blink reflex is exactly that: a reflex that is involuntary. Obviously someone could purposely stare into the beam, even holding their eyelid open with their fingers, but that would be a great deal of stupidity on their part. Most people stop doing something that hurts, and the only reaction required here is looking away or letting your eyes blink when they want to.
millirad
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It was risky, but no one was hurt. I would be more cautious though. It looks very cool and I did enjoy seeing it to be truthful, but I'm thinking the beam will hurt, at least as much as a photo flashbulb going off at point blank distance. I'm more worried about someone who would be purposefully trying to injure spectators, which you clearly were not trying to. A 1W 445nm can be very hazardous for obvious reasons. Please be safe and I won't lie, I enjoyed the video.
Just wanted to acknowledge Benm's post here. It perfectly correlates with the fact that at no point in time did I have the beam ever remaining in a position where even if a person wanted to stupidly keep their eyes exposed to the light they could particularly at 800 meters out when the NOHD 0.25 sec exposure distance was 222 meters.
I would never have done anything that would have jeopardized anyone's vision even temporarily.
-Scott
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flogged
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Re: Video: 1 Watt Pocket Blue Laser Shining Down from the Eiffel Tower
I don't think the beam was unfocused.. rather it had expanded as it traveled (several hundred meters?) to camera.
{edit} perhaps a bit reckless to do this.. however after traveling for > 200 meters the beam has diverged to where it's not nearly as dangerous, at least compared to being close to the aperture.
something just dose not seem right about shining that all over Paris . The beam looks pretty unfocused but I hope your friend isn't blind now. I wish I was able to go up in the tower when I was in Paris last summer
I don't think the beam was unfocused.. rather it had expanded as it traveled (several hundred meters?) to camera.
{edit} perhaps a bit reckless to do this.. however after traveling for > 200 meters the beam has diverged to where it's not nearly as dangerous, at least compared to being close to the aperture.
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Re: Video: 1 Watt Pocket Blue Laser Shining Down from the Eiffel Tower
Lets end the BullShite.
Tomorrow when my other laptop is fixed I'll run the numbers in Skyzan software.
The OP getting me a accurate distance in meters from his camera position to the base of the tower would be appreciated.
Heights from the base to the first and second levels would be appreciated.
That way I can use the software's slant range features and get a corrected calculation, as the angle does matter a bit.
As poor as the mode quality and optics are on a 445, I doubt there was much of a issue.
This hazard at 3 miles thing needs quantified.
Ladies and Gentlemen, lets do some math before we shout Jai'accuse.
Steve
Lets end the BullShite.
Tomorrow when my other laptop is fixed I'll run the numbers in Skyzan software.
The OP getting me a accurate distance in meters from his camera position to the base of the tower would be appreciated.
Heights from the base to the first and second levels would be appreciated.
That way I can use the software's slant range features and get a corrected calculation, as the angle does matter a bit.
As poor as the mode quality and optics are on a 445, I doubt there was much of a issue.
This hazard at 3 miles thing needs quantified.
Ladies and Gentlemen, lets do some math before we shout Jai'accuse.
Steve
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Re: Video: 1 Watt Pocket Blue Laser Shining Down from the Eiffel Tower
The height to the top publicly accessible area of the Eiffel Tower is approx. 280 meters. The height of the second level is approx. 115 meters. The camera around which I was tightly shining the laser beam was 750 meters out.
This gives a distance from the top to where I was beaming of approx. 800 meters. For the second level the distance was approx. 760 meters.
I look forward to reading your calculations.
Thanks,
-Scott
The height to the top publicly accessible area of the Eiffel Tower is approx. 280 meters. The height of the second level is approx. 115 meters. The camera around which I was tightly shining the laser beam was 750 meters out.
This gives a distance from the top to where I was beaming of approx. 800 meters. For the second level the distance was approx. 760 meters.
I look forward to reading your calculations.
Thanks,
-Scott
First of all, a video frame showing how "bad" the flash would look to a human isn't accurate, since the sensors in cameras over-accentuate bright flashes. No win there.
And even if the flash DID look like that, it's only on ONE FRAME of video - it goes by quicker than a flashbulb (which i would probably find more distracting while driving).
Still, this video proves a larger point - for 99% of people who buy lasers, the only true practical use for them is to show off to your friends
And even if the flash DID look like that, it's only on ONE FRAME of video - it goes by quicker than a flashbulb (which i would probably find more distracting while driving).
Still, this video proves a larger point - for 99% of people who buy lasers, the only true practical use for them is to show off to your friends
Re: Video: 1 Watt Pocket Blue Laser Shining Down from the Eiffel Tower
Results of software calculations:
445 nm 1.5 mR, 1.2 watts, Initial Diameter 2 mm:
Calculated distances, .25 second standard exposure based on average blink time, ie the accepted norm for doing the calculation for a inadvertent exposure.
163 meter NOHD
824 meter SZED
3650 meter CZED
Angle change was insignificant over the straight line shot.
NOHD is nominal ocular hazard distance.
SZED is aviation sensitive zone exposure distance
CZED is aviation critical zone exposure distance.
SZED is 1.0 x 10-4 watts/square cm
CZED is 5.0 x10-6 watts/square cm
* note that changing the ID at this distance from 1 mm to 2 mm is less then 1% change in results, so I did not list it.
So at the roughly 800 meter distance the OP claims his target was at, you are at almost 5 times the hazard distance.
You are, however, roughly at the outer edge of the region where the US FAA and international convention believes that temporary flash blindness and afterimages can interfere with critical task performance. No damage occurs, but task completion is impaired.
I would caution that in the future, please consider that a camera with a optically aided, direct, viewfinder, like a SLR could have collected more light and focus it onto the retina. This is not a issue for indirect, ie LCD viewfinders.
Considering the quality of the beam from a 445 nm multimode diode, 1.5 mR is probably being generous to the diode. I would imagine it is worse.
Steve
Results of software calculations:
445 nm 1.5 mR, 1.2 watts, Initial Diameter 2 mm:
Calculated distances, .25 second standard exposure based on average blink time, ie the accepted norm for doing the calculation for a inadvertent exposure.
163 meter NOHD
824 meter SZED
3650 meter CZED
Angle change was insignificant over the straight line shot.
NOHD is nominal ocular hazard distance.
SZED is aviation sensitive zone exposure distance
CZED is aviation critical zone exposure distance.
SZED is 1.0 x 10-4 watts/square cm
CZED is 5.0 x10-6 watts/square cm
* note that changing the ID at this distance from 1 mm to 2 mm is less then 1% change in results, so I did not list it.
So at the roughly 800 meter distance the OP claims his target was at, you are at almost 5 times the hazard distance.
You are, however, roughly at the outer edge of the region where the US FAA and international convention believes that temporary flash blindness and afterimages can interfere with critical task performance. No damage occurs, but task completion is impaired.
I would caution that in the future, please consider that a camera with a optically aided, direct, viewfinder, like a SLR could have collected more light and focus it onto the retina. This is not a issue for indirect, ie LCD viewfinders.
Considering the quality of the beam from a 445 nm multimode diode, 1.5 mR is probably being generous to the diode. I would imagine it is worse.
Steve
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Steve,
Thank you for your excellent addition to this thread. You essentially confirmed what I have been saying all along. I did consider the camera issue you mention which is also part of the reason that I did this as late as possible on a cold night such that there would be virtually no one around and particularly no one in the vicinity of where I positioned the LCD screen based video camera.
Cheer and +rep!
-Scott
Thank you for your excellent addition to this thread. You essentially confirmed what I have been saying all along. I did consider the camera issue you mention which is also part of the reason that I did this as late as possible on a cold night such that there would be virtually no one around and particularly no one in the vicinity of where I positioned the LCD screen based video camera.
Cheer and +rep!
-Scott
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See, this is why people call us nerds - a thread begins with a cool video of a guy having fun with a laser on top of the Eiffel tower... and ends with someone using a calculator to figure out if it actually WAS fun...
I think being "into" lasers is by default nerd country. I think folks who are out of touch with their inner geek cannot fully appreciate what it means to be able to shine a highly visible beam of concentrated illuminated beauty down 800 meters! Also for some folks (myself included) it's cool/fun to calculate something and thereby better understand it. :beer:
Cheers!
-Scott
DJNY
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See, this is why people call us nerds - a thread begins with a cool video of a guy having fun with a laser on top of the Eiffel tower... and ends with someone using a calculator to figure out if it actually WAS fun...
This forum isn´t just a simple magic show where you´re astonished and nothing else. We have many scientist around which tend to look behind the curtains. Without these people, this forum would be as boring as the million other out there.