The Eurofurence Forum
Eurofurence Information => Questions & Answers => Topic started by: sneeuwvos on 31.01.2016, 20:01:03
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Last year at the disco's there were lasers (love lasers btw!) but what I totally did not like was lasers hitting the large disco ball hitting my eyes.
I don't want to be a party-pooper, but this internet meme comes in to my mind.......
(https://i.imgflip.com/ycxjy.jpg) (https://imgflip.com/i/ycxjy)via Imgflip Meme Maker (https://imgflip.com/memegenerator)
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Hi there!
I'm the one in charge of the lasers at EF and I work with lasers on a daily basis for several years already and also attended a seminar to be “Laserschutzbeauftragter” (laser protection officer) according to german law. So it's no problem at all to explain why it in fact is safe and provide a few numbers. It might turn out very technical though but I hope it can still calm you. :)
First of all, here is an overview of what systems were used in last years setup:
eight ECS 3000 RGB lasers, with 600mw 637nm red, 800mw 520nm green, and 1600mw of 445nm blue were used in the back and one 12W RGB laser was used to write on the laser screen.
The technical explanation is that the eight ECS 3000 on stage had the blue dimmed down to 50%, about 800 mw output for a pretty warm white balance (so max. output with white is 2.2W)
The software in use is Pangolin Quickshow, scan speed was set to 30.000PPS. Safety card was turned on, the lasers do have shutters and Quickshow was set up in a way that no straight beam shot was possible.
While last year there was no direct audience scanning, there was a mirror ball which reflected the laser beams.
Now is that safe?
Yes it is, and this is why:
When the laser beams emit from this laser model their diameter is 4mm, and the divergence is 1.0mrad.
The distance of the mirror ball from stage was at least 25m, not counting the distance of the ball to the ground and the fact mirror balls are made from really low quality mirror material that would destroy the beam quality.
Those facts would lead to a beam having a diameter of 29mm in the best possible case, with a level of 2.4mw/mm².
Lasers that are considered safe (class 3R) have a level of 5mw/mm².
So even if all factors of safety fail and you'd have a straight beam shoot at the mirror ball and it would bounce off straight inside your pupil, with all color on, you'd still be safe :)
The only reason I don't, for now, do audience scanning, is for everyone with a camera as it could cause dead pixels :)
Laser damaged camera sensor / video projector - was it dangerous for human eye as well?
If your camera sensor or video projector has been damaged by laser beams, the show was not necessarily dangerous for human eye:
Camera sensors and video projector LCDs are much more sensitive to light impact than human eye.
If filmed from a distance, lasers normally don't harm camera sensors, but if you zoom into the beam, the optics act like a burning glass - and focus the already very sharp beams to the sensor (which in most cases is also no "real size" sensor, but a smaller one -> even more impact)
Human eye does not zoom, and the reception area is much larger compared to the actually projected image on the retina.
Conclusion:
A safe laser show (class 3R in MPE area) does not harm human eye, but can damage your camera/photo sensor or video projector.
Just last weekend, 24 x 10W + 4x 35W with audiance scanning with a distance of around 20M :
(http://nsa37.casimages.com/img/2016/01/31/160131100934610147.jpg) (http://www.casimages.com/i/160131100934610147.jpg.html)
And this :
(http://nsa38.casimages.com/img/2016/01/31/160131100934717419.jpg) (http://www.casimages.com/i/160131100934717419.jpg.html)
And a little video a did back in Prague with 8x 30W RGB and 8x 8W green with straight audiance beam : https://www.youtube.com/watch?v=aQBg8UYBJOI
Also, I'm thinking, together with Snow-wolf601 that also has a laser licence for Germany ( Laserschutzbeauftragter ... ) to host a panel next year on stage about laser show and safety on theml :)
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Thanks Djem for your explanation. I feel better now (but will always be careful with them still)
I came to this question because when I was younger and in school a school mate didn't believe lasers were harmful so he aimed a laser pen (1Mw if correctly) right in his own eye at around 15 cm for half a minute. I didn't see him for quiet some time after that (due to the fact I switched school, not became he lasered his head off haha) but when I saw him years later someday he was wearing glasses. Might be because of the laser, or not.
Never knew audience scanning was called that way.
If you are doing a panel this year i would be happy to attend.
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If you are doing a panel this year i would be happy to attend.
I would also be interested in that panel :)
So long,
Honigeintopf
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Thanks Djem for your explanation. I feel better now (but will always be careful with them still)
I came to this question because when I was younger and in school a school mate didn't believe lasers were harmful so he aimed a laser pen (1Mw if correctly) right in his own eye at around 15 cm for half a minute. I didn't see him for quiet some time after that (due to the fact I switched school, not became he lasered his head off haha) but when I saw him years later someday he was wearing glasses. Might be because of the laser, or not.
Never knew audience scanning was called that way.
If you are doing a panel this year i would be happy to attend.
Lasers are quite cool things, but they can be dangerous as well, so asking is quite fine I think. German regulations are pretty strict, that is why we did not have lasers at EF for quite a long time.
The 1 mW laser your friend used, is considered eye safe if the exposure is up to a quarter second! That the device is declared "safe" is due to the fact, that normally the eye lid would close, the person would look away or the spot moves enough so that the exposition on your retina is less then .25 seconds. Looking into it deliberately for 30 seconds... welll... don't do that!
There were incidents long long ago (still in Nuremberg, so that was EF 11 or 12) when some guy was using a 30 mW and even a 100 mW laser pen with very small light dot outside the castle. Now - at those powers even a reflection from window would not be considered eye safe. (High power, small spot, probably not moving). Also he tried to convince me that they are safe by lighting his own eyes (moving the spot rapidly).. but yeah... he got quite some people angry.
Btw: when somebody notices the effects of retina damage due to laser burns, about 30 % of the retina are already irreversibly destroyed. Our brain is really good in making up the missing parts so long so that we don't notice the damage. (At least that's what I was told when working in a company which produces laser based sensor-equipment)
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As a word of caution to this: There will be NO access to the balcony above the main stage at any time while the laser system is armed. The only exception there would be stage technicians.
Last year we had to get a few attendees down from there that where taking photos with DSLRs straight into the lasers. Yeah, please don't be that stupid! ;3
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Ironically, they also repair bad eye sights with lasers :)
(https://lh3.googleusercontent.com/-dhrA3nOXM5E/VTwBbGBIZ8I/AAAAAAAA78A/sAfZR7FaJIo/w270-h225/a9fdc02550313d98eb0ac804e78a88f8.gif)
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As a word of caution to this: There will be NO access to the balcony above the main stage at any time while the laser system is armed. The only exception there would be stage technicians.
Last year we had to get a few attendees down from there that where taking photos with DSLRs straight into the lasers. Yeah, please don't be that stupid! ;3
Thank for taking care of that.
Last year I even caught hotel staff taking a break there and just watching :) It's not dangerous, but better play safe.
And no good place to take picture or movies :
(https://i.ytimg.com/vi/onkey5D3Yfk/maxresdefault.jpg)
(http://www.hdcamteam.com/wp-content/uploads/2011/07/Sensor_Damaged_by_Laser.jpg)
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;_; I missed your session this year about the Laser Safety, I was attending another important session at EF22.
Just wanted to say; The lasers looked a lot better than previous year, and I saw no pointing at the disco ball either anymore :) Keep up the good work.
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;_; I missed your session this year about the Laser Safety, I was attending another important session at EF22.
Just wanted to say; The lasers looked a lot better than previous year, and I saw no pointing at the disco ball either anymore :) Keep up the good work.
No, me neither, however I was surprised by some 'stray lights' that bounced from (at least one) of the scanners.
(http://image.ec21.com/image/dragonflylighting/oimg_GC06957893_CA06958121/LED_Scanner_60W_Disco_Lights_LED_Stage_Lighting.jpg)
I was surprised that it even found an angle as both the lasers and these move rather quickly.
And it had to be angled half way the stage and partly downward to reflect the lasers.
I had followed them for a while out of curiosity, and saw it happen a couple of times more but arcing them above head level and more toward the ceiling.
I post this as an observation, as an observer I just thought it looked cool.