-WARNING- Using Live View Near LASERS!

Hi - my first post on this forum and this is an interesting subject.

After a bit of searching, I have found a youtube vid where pretty much exactly the same 'cross hair' appears after laser exposure to a sensor..

http://www.youtube.com​/watch?v=onkey5D3Yfk&N​R=1

I hope the OP managed to get his 1D Mk3 sorted (under insurance from the events company?)

I believe that of late the class three lasers are banned in Canada. There have been a few incidents around airports where punks use them to temporarily blind pilots and generally disrupt air traffic. If caught, these idiots get really serious jail time.

But getting one of these directly on the sensor would probably have the same effect as aiming the camera full into the noonday sun on a clear, cloudless day with the mirror up.

WOW!

Thanks for the heads up. Wouldn't have thought of this happening if I hadn't seen this, but that isn't nice.

Just hope that they aren't using class 4 lasers for this sort of gig as there's suggestion that some entertainment lasers are class 4 (serious risks associated...)

( http://en.wikipedia.or​g/wiki/Laser_safety - interesting!)

VERY irresponsible light tech and I think I would have spanked him hard. I'm an audio engineer and have done countless live shows and that is unacceptable focusing...NEVER at eye level ! ! ! !

I'm glad I came across this thread - I'll keep this in the back of mind when I'm out and about.
Do lasers only kill the sensor if they are directly in the line of fire?

chrismid259 wrote in post #11619745
Do lasers only kill the sensor if they are directly in the line of fire?

as long as you are not dealing with illegal or scientific lasers you can safely shoot the beams or reflections (i.e. the dot of a laserpointer on a wall), as long as the laser is not reflected by something highly reflective like a mirror (obviously). just don't (ever) point the camera in the direction of the laser source, and while you're at it keep your eyes off of it too. you can only look twice into a laser...

Thanks for the info folks. I might never have thought of this.

good to know...

First off I doubt very seriously that this damage came from a Laser. I work with Lasers every day in my work and have a very high degree in training of them, as well I teach Laser Safety.

Im gonna answer a couple of questions asked through out this post but im not going to take the time to go in and quote each one.


General Classification of Lasers

Class 1 Are eye safe Lasers
Class 1 M Eyes Safe unless viewed through a Magnified Optic
Class 2 Can on be a VISIBLE Laser and is safe in that eversion response ( Blink Reflex} is enough (.25 seconds ) to break the amount of energy the eye recieves and to there for make it "SAFE"
Class 2M Same as a class 2 except there is a Hazard viewing through Magnified optics.
Class 3 R This used to be labeled Class 3 R and is a Medium powered System. This can be IR or Visible spectrum and has an NOHD ( Nominal Occular Hazard Distance ) requirment.
Class 3B This used to be labeled Class 3b, again a Medium Powered system and has an eye and Skin hazard at certain distances.
Class 4 High powered system, most powerfull class of Lasers, there are some Lasers out there that are class 4 that r capable of cutting up to three inch steel.


LASERS have a seperate HAZARD when viewed through a Maganified Optic when looking at the beam as a direct source or through Specular or, Diffuse Reflection ( all three are exsplained below ). This is a huge concern with anyone in the arae of where your using that LASER. If you view a LASER through any optic what happens is it takes a beam that is focused, and it refocuses it. Grunt terms makes a smal source smaller and a powerfull source much more powerfull. So depending upon the magnification of the optic it can increase the NOHD of the system significantly. For example if the NOHD of a system is lets say 1Meter and you view that LASER through a 5CM optic, your NOHD would be 4x greater. So your New NOHD is now 4 Meters. A good rule of thumb is to take the NOHD and times it by the power of the system and add 25 Meters.

There are three different types of viewing of LASERS.

Direct Source viewing is looking directly into the apeture of the system outputting the Laser.
Specular reflection is a reflection of the beam off a Mirror like or flat reflective surface where the beams carries the same power of the direct source of the beam.
Diffuse reflection is a reflection off of any type of flat or porouse surface ( does not have to be reflective ie... plywood, a wall etc.) in which the radiation scatters in all direction. This is limited to High powered system, CLASS 4, and the scattered radiation carries the same amount of power as the direct source of the beam.

In order to black a specifice wave length of laser your filter would have to have a filter that blocks that exact wavelength and the OD ( Optical Density ) for the power output.

Wavelengths of Lasers effect the eye differently. So depending upon the wavelength of the Laser you will effect or damage different parts of the eye. Great example is 532NM wavelength. Its quickly becoming a favorite color of LASER for Military for there Hail and Warning tools because of its effect on the Human eye at specific irradiance levels that provide a Hail and Warning effect or suppresion effect with high enough power output. But is still eye safe as long as the MPE is not exceded for the distance the target is at. So basically as long as your outside the NOHD your safe no matter if it hits you in the eye or not. This specific Wavelength effects the Retina. But a other Lasers can effect just the cornea. As well certain colors can create a photochemical reaction within the eye and cause other effects, such as certain blue or purple wavelengths.

As I said I dont think this Laser caused this damage. I have hundreds of Photos and Videos taken and recorded during testing and training videos, where Lasers where fired directly into CMOS cameras and Video Recorders for MUCH MUCH longer than a split second with no damage. We contacted Sony, Canon, Nikon, and JVC prior to this filming to find out if sensors would be damaged based upon the power out put that is put out by these Lasers, each manufacturer put us in touch with there engineering staffwho in turn worked with us to find out the exact MW per Square CM on each sensor and determine if it would damage the equipment. NOT ONE camera suffered damage. and we exsposed them to much longer then split second bursts.

Most Laser light shows do use Class 3 LASERS however the MPE is normally never exceded because the systems NOHD is very close, Meaning if the NOHD is 3 Feet and your are 3.1 Feet or farther you are fine.

And lastely please dont use Wikidpedia to quote things from its a crappy source, anyone can go in and change the information to read what ever they want.

FAST_Marine wrote in post #11636481
First off I doubt very seriously that this damage came from a Laser. I work with Lasers every day in my work and have a very high degree in training of them, as well I teach Laser Safety.

then where does the damage come from? care to elaborate?

also your post would be much more valuable if you wouldn't use abbreviations that nobody understands. NOHD? MPE?

a reflection carrying the same energy as the beam? 100% reflective surfaces? i take it you work with NASA then...

how does a coherent, parallel beam lose power over distance? and we're not talking infinity here, you said 3ft vs 3.1ft?

you said you fired a laser for much longer than in the videos at your sensors. this information is pretty much useless without knowing at least the output power of the laser. i can take an el-cheapo laserpointer that maybe outputs 0.5mw, and shine that at my sensor until the batteries run out and nothing will happen, but that doesn't tell us anything about the several 100 mw that are used at laser shows...

so please don't take this as an offense, but without putting some comparable values in your statements it doesn't really explain anything.

To me he was trolling, wikipedia a crappy source? lol...

peter173 wrote in post #11638007
To me he was trolling, wikipedia a crappy source? lol...

No Peter I wasnt Trolling, and yes Wikidpedia is a crappy source. Anyone can go in there a change a definition in Wikidpedia.

Kendon, The abreviations for those things you stated are spelled out in the post, as well some of those abbreviations are mentioned in earlier posts and are talked about in more detail. the first time an abbreviation is used it is spelled out right next to it. But since you called out those two abbreviations specifically ill be happy to define them.

NOHD is NOminal Occular Hazard Distance, this is the distance from the aperture of the system to your eye in which you are safe and no eye damage will be incured. Grunt terms eye safe distance.

MPE is Maximum permisable Exsposure Limit, this is the Maximum allowable energy within a set distance that an eye can be exsposed to Laser radiation before damage will incure.

Yes a specular reflection will carry the same energy of the main beam due to the fact that the is merly redirected. Since this is a Hazard more comin in HIgh Powered systems, the amount of fall off from the redirection is so minimal it wouldnt make a differance. Here is an example.

If the NOHD if a system is 50 feet and you fire that LASER at lets say a Mirror and you are ten feet away. If that beam hits that mirror on the right plane and the right angle to reflect back toward your eye and hits you then there is a very high probability you will incure eye damage. The reason is NOHD is a cumulative measurment . The 10 Feet there and 10 Feet back dont equal to greater than 50feet and therefor you r still within the NOHD. Now if you shot the LASER from a distance of 26 Feet and it hit the Mirror then 99.9999999% of the time you will be fine, but there is always the fluke accident.

Every LASER in the US that is higher than a Class 1 must have a label on it. This LABEL must have the Power Output of the system and the NOHD on it.

Yes it is a coherant beam, but what you are not accounting for is beam divergance ( spread of the beam). Every LASER is built for a differant thing. A LASER pointer is designed to point things out , so the beam is very tight and has a very low divergance. But a LASER for a LASER light show or a LA-9P ( Military Hail and Warning LASER ) is specifically designed to spread over distance so it has a much larger divergance, in this case about an 18 inch spread every 100 Meters. So the NOHD is based upon the size of a Laser and how much energy it can place on the eye over distance as well as the type of Laser Wavelength, the Beam Path and the LASER beam profile ( Top Hat, Gausian etc...). So in my example the Maximum Permissable Exsposure Limit (MPE) set that Nominal Occular Hazard Distance (NOHD) at 3Feet because of that beams power output and divergance exceded that MPE at 3 Feet, beyond 3 Feet the amount of energy now being placed on the eye is less than the MPE and there for "SAFE"

Come on Kendon, do the pictures I posted look like a .5mw Laser to you, but hey ill be happy to share it with you. One of those Lasers is a 250MW system on pulse mood, on continuous it drops to about 175MW of power ( all Lasers do this but its to much to type to go into ) and the other is a 1W System.

Yes I wrote this at 11 pm last night and was trying to be as vague as possible for certain reasons, as well as to keep it as simple as possible so as to not have people think I work for NASA ( which I dont ).

I have no clue, but based off of the conversations with Canon, Nikon, JVC, and Sony's technical personel a 532NM LASER System up to and slightly above 1W will not damage the sensor on any of the Cameras we were using, and we used everything from the 7D, 5DMKII, Nikon D300, Nikon D3, Sony Digital HD Records, JVC Digital HD Recorders and a slew of other recording systems, in all to gather more than 150 Hours of digital images.

More than 50% of this digital movie gathered has LASER's pointed directly into the lens of the system being used to record ( both Still and Video ) with no adverse effects. And at distances from far away to as close as 3 feet. In the case of the 7D, i use this camera just about every day and it has no deffects what so ever.

thank you for the explanation. some stuff is clearer for me now.

what i am still wondering is, with a 1W laser at 532nm you can pop ballons, burn stuff and even cut dark plastic (youtube->cd cases for example). you can do that with even lower power. how can this NOT damage the sensor? properly focused and given some time it could cut through the body and fry the sensor. if i am totally wrong here please let me know...

also i see the point you are making with the beam spreading, but let's be honest here, a show laser doesn't spread that much as you described. the distance of most of the videos is pretty close, and the lens will narrow the beam down to a very tiny spot on the sensor. if you can/want to share that information, at what beam diameter and exposure time is the sensor safe according to manufacturers?

last but not least there might be more to it than just the heat generated by the laser, but from here it would be only speculation as my knowledge doesn't really extend to the inner workings of cmos sensors. might be that the pixel(-colum/-row) gets only fried when the laser hits it in a destinctive state during readout or something.

Ill see if our Video department still has the Data from the Camera Manufacturers or if they said a threshhold to stay under.

If you look at those videos you will notice, that the Baloons have to be Black and the Plastic is a Dark color, this allows for heat generation, as well from the ones ive seen on there they are doing these things at extremely close ranges, most of them just feet away. This is definatly within the NOHD or NSHD ( Nominal Skin Hazard Distance ). Sorry forgot that one in my last post same as NOHD but for the Skin. Yes some of these will burn the hell out of you.

IN the Realm of Lasers actually LASER light show Lasers spread alot, it really doesnt take alot of beam spread to kill the irradance level of these things. In most case you see a dramtic shift in the power of these things with less than a hlaf degree change in beam divergance. Ill give you an example, a 990MW system, in the 860NM region that is a Class 4 Laser named an IZLID has and NOHD of 850 Meters. It has a Beam Divergance of less than Half a degree. and has a target pointing range of 40K. Thats a very tight beam but its NOHD isnt really that far, it has a Zoom funtion on it that allows it to flood, if that flood was turned all the way and left in the open position its NOHD would be less than a quarter of its dialed down NOHD ( its not that way though because NOHD is based off worst case, in this case the dialed down pointer).

I have looked at alot of these pictures from these light shows and the beams seem to show a huge divergance and alot of beam fall off. I did notice on some of the sites I saw that these systems tend to be powerfull, one in case was a 4W YAG system. YAG is a type of crystal used to produce a specific wave length, in the case of a green laser they some times use a YAG crystal which has a wavelength of 1064 and place a frequency doubling crystal over it to get 532NM. But I dont knowany of the important numbers to run the equations to see what the actual power of these things are at what distance.

Now I can tell you ( most people dont know this ) that the FDA is responsible for LASERS. Any LASER made or produced is actual registered with the FDA for specific wavers and exemptions, so if it is built and designed for a LASER light show it would need a certification or exemption letter from the FDA before it could be used for that purpose, the same goes for companies that make them for the military and such. As well there are standards for building Lasers and the safety measures that are required by law before you can get them approved for use (ie.. remote interlocks, horns and sirens).

Honestly I dont know. Military LASERS are some of the most powerfull in the world and dont have to meet alot of the specifications that commercial systems do. I can only tell you what i saw based off my first hand knowledge of more than 50 film shoots for traning and testing. The only issue we ever had with a camera is we smoked a PHANTOM ( its an exspensive high speed camera ) with a 3W designater that has a beam divergance of less than .25 Degrees and has an NOHD of over 1K. This was due to the camera was to close and we shoot an 860nm beam directly into it and fried the sensor. Before everyone says seeeee, comparing a 3W military target designator to a Laser Light Show Laser is Like comparing Lucile Balls to Marilyn Monroe in the looks department.