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04-25-2013, 12:07 AM   #16
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And further regarding green lasers: "...green lasers are also more dangerous. Green is more easily absorbed by the retina than red, so it requires less exposure to cause damage. "

04-25-2013, 04:03 AM   #17
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QuoteOriginally posted by caver3d Quote
No, you don't want to use (point) a green laser pointer on human subjects either.

BTW, I also have the Sony V1, and have always been amazed that they put the laser function in the camera (makes it a collector's camera, along with the night vision feature and ability to shoot IR). The camera came out 9-10 years ago which was not that long ago. The concern about laser pointers was well in force at that time too. So, it is not just a safety concern today.
I meant that the camera might be more sensitive to the green laser light, not that it would be safer for a persons eyes. I already bought one (made the mistake of buying from a new seller or one that hadn't sold in a while anyway and the payment is unclaimed so there might be a delay). It is green and comes with 5 caps that project different patterns. I can always defocus the beam a bit with a lens if I feel I need to. I don't want the ability to be able to shoot at someones face but it would be good if it were non harmful in the event that the laser grid accidentally crosses someones face. It seems some can be focused to burn things (not sure about the one I got). The advantage might be that beyond the point it is focused, the beam spreads (but then again I can make it do that with lenses I have anyway). I'll just have to wait till I get it to see how it works. With the lenses I have I can easily make the beam (on the red lasers I already have anyway) spread to a few inch circle even at close range. I'll have to see how such a lens works in combination with the pattern lenses that comes with the laser. I will of course use much caution about hurting any ones eyes and would not intentionally aim it at someones face regardless.

If you want to see the kind of laser I got, search "5 in 1 green laser" on ebay. there are several similar ones.
04-25-2013, 05:08 AM   #18
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QuoteOriginally posted by ripit Quote
So what about laser color?
QuoteOriginally posted by JinDesu Quote
If it's CDAF, I would wildly guess that because a bayer sensor has twice as many green sensors as blue and red, the sensor would react better to a green laser.
QuoteOriginally posted by caver3d Quote
And further regarding green lasers: "...green lasers are also more dangerous. Green is more easily absorbed by the retina than red, so it requires less exposure to cause damage. "
Don't use green. Please. Human eyes are more sensitive to green than other colours, correct, but also green lasers are, by design, more powerful than red (you basically can't make a very low-power green laser, and generally manufacturers don'T filter them to reduce the output).

In short, use a class 1 laser, no more. Or better yet, take an online laser security course before playing with lasers. A laser is not a toy and I have seen enough laser accident reports during my university days (and met firsthand with a girl who lost the use of one eye in one such accident). No need to add to that list.
04-25-2013, 05:17 AM   #19
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QuoteOriginally posted by bdery Quote
Don't use green. Please. Human eyes are more sensitive to green than other colours, correct, but also green lasers are, by design, more powerful than red (you basically can't make a very low-power green laser, and generally manufacturers don'T filter them to reduce the output).

In short, use a class 1 laser, no more. Or better yet, take an online laser security course before playing with lasers. A laser is not a toy and I have seen enough laser accident reports during my university days (and met firsthand with a girl who lost the use of one eye in one such accident). No need to add to that list.
There are reasons no one offers a laser assisted AF system any more......

04-25-2013, 08:34 AM   #20
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QuoteOriginally posted by Docrwm Quote
There are reasons no one offers a laser assisted AF system any more......
The laser beams offered by Sony were not dangerous. No more than a bright light. Toying with lasers when you don't know what you're doing CAN be dangerous, however.
04-25-2013, 09:00 AM   #21
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QuoteOriginally posted by bdery Quote
The laser beams offered by Sony were not dangerous. No more than a bright light. Toying with lasers when you don't know what you're doing CAN be dangerous, however.
Yes, but they stopped using them, at least in part, because of the perception by others that they were dangerous and because the encouraged others without the technical expertise to experiment with lasers and AF. I own a Sony DV video camera and had that very negative reaction from several people to being painted with criss-cross laser beams when it was trying to focus.
04-25-2013, 09:29 AM   #22
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Using the red lasers with the lens tips that are coming with the green laser might be an option. I'll have to try it out.
04-25-2013, 09:31 AM   #23
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QuoteOriginally posted by bdery Quote
Don't use green. Please. Human eyes are more sensitive to green than other colours, correct, but also green lasers are, by design, more powerful than red (you basically can't make a very low-power green laser, and generally manufacturers don'T filter them to reduce the output).

In short, use a class 1 laser, no more. Or better yet, take an online laser security course before playing with lasers. A laser is not a toy and I have seen enough laser accident reports during my university days (and met firsthand with a girl who lost the use of one eye in one such accident). No need to add to that list.
online laser security course

Could you elaborate on that? Is this a paid training certification or just something free I could find somewhere?

04-25-2013, 09:50 AM   #24
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We are talking about changing a passive device, recognized by the entire world as such and converting it to an active, harmful device.


Cameras, as passive devices, are made to be pointed at people. A billion people in the world could pick up an SLR and point it at someone without the slightest thought. I've had many people come to my house and pick up one of my cameras and start firing away. They do that without out asking or thinking.

A unsuspecting person could walk into a room, pick up the altered camera, and fire away. That camera is an active device that could severely hurt people.

Anyone who walks into a room and sees a gun, knows that it is an active harmful device. They know pointing it at someone could severely hurt them.

p.s.
I know there are people who consider cameras as active, soul catching devices. This is immaterial to my point. We are talking about facts, not beliefs.

p.p.s.
I've had someone come into my house, pick up my loaded film F1New SLR, with the motor drive attached and take 36 pictures of my kitchen wall before I could say no. Many times my cameras are out of their cabinet as I prepare use them or put them away after use.
04-25-2013, 10:13 AM   #25
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QuoteOriginally posted by lmd91343 Quote
We are talking about changing a passive device, recognized by the entire world as such and converting it to an active, harmful device.


Cameras, as passive devices, are made to be pointed at people. A billion people in the world could pick up an SLR and point it at someone without the slightest thought. I've had many people come to my house and pick up one of my cameras and start firing away. They do that without out asking or thinking.

A unsuspecting person could walk into a room, pick up the altered camera, and fire away. That camera is an active device that could severely hurt people.

Anyone who walks into a room and sees a gun, knows that it is an active harmful device. They know pointing it at someone could severely hurt them.

p.s.
I know there are people who consider cameras as active, soul catching devices. This is immaterial to my point. We are talking about facts, not beliefs.

p.p.s.
I've had someone come into my house, pick up my loaded film F1New SLR, with the motor drive attached and take 36 pictures of my kitchen wall before I could say no. Many times my cameras are out of their cabinet as I prepare use them or put them away after use.
Wait a minute! Nobody every said anything about stealing souls! Cameras do that? They need to put a warning!!!!!!!!!!!!!!










Just kidding.


I wouldn't go hacking up my nice new camera. I'm thinking something hot shoe mountable and removable. I have no problems doing some research into the area of laser safety nor do I have a problem trying to make something with a low safety risk. The tip that projects the laser into a pattern is reducing the intensity of the light and I can do it further if necessary with lenses. It would also be a removable device. Using the tips off the green laser on a red laser with or without lenses is an option. Right now I'm trying to figure out how to measure the lasers intensity (without buying a specialized meter). I'm kind of wondering if it can be done with a digital camera or the light meter on a film camera in a similar manner to how you would calculate ev. If the intensity has been reduced to the point where it is not suspect of being harmful to the human eye, its probably not going to be harmful to a camera sensor either so I could even aim the laser into the camera lens if necessary. I guess I also need to look into what intensity of light is considered safe for the yes too.
04-25-2013, 10:21 AM   #26
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QuoteOriginally posted by ripit Quote
Using the red lasers with the lens tips that are coming with the green laser might be an option. I'll have to try it out.
Yes, or buy a 1$ red laser that comes with tips built-in or at least designed for it.

QuoteOriginally posted by ripit Quote
online laser security course

Could you elaborate on that? Is this a paid training certification or just something free I could find somewhere?
Basic Laser Safety - Introduction - www.LaserFX.com

Laser safety - Wikipedia, the free encyclopedia

This is what I found in two seconds.

Of course the best is to have an actual training in laser safety provided by a knowledgeable ressource (the training we had in graduate school took half a day. And that was for people using lasers everyday, familiar with them). But this is a start.

I'll say it again : lasers are not toys, and should be treated with the same level of awareness as a knife or baseball bat.
04-25-2013, 10:39 AM   #27
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QuoteOriginally posted by bdery Quote
Yes, or buy a 1$ red laser that comes with tips built-in or at least designed for it.



Basic Laser Safety - Introduction - www.LaserFX.com

Laser safety - Wikipedia, the free encyclopedia

This is what I found in two seconds.

Of course the best is to have an actual training in laser safety provided by a knowledgeable ressource (the training we had in graduate school took half a day. And that was for people using lasers everyday, familiar with them). But this is a start.

I'll say it again : lasers are not toys, and should be treated with the same level of awareness as a knife or baseball bat.
I'm not sure I could find one locally buy a red one like the green one I got seems to be about $6 or less on ebay. About the best I have found are some mit online video classes on lasers (hours long so pretty indepth) but scanning through I don't seem much on safety, just theory (I'll probably watch some anyway).

I already understood the hazards presented in the first link you gave, I just haven't found solid info on determining if a particular laser is risky (I gather the intensity can be reduced to safe levels if they use them in light shows and its approved to sweep people with them, now its just a matter of figuring out how to measure the intensity after the beam has been modified by whatever lenses). I'll keep looking though.
04-26-2013, 04:47 AM   #28
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QuoteOriginally posted by ripit Quote
I just haven't found solid info on determining if a particular laser is risky
As I've written before, any Class I laser is safe, class II or more are dangerous.

QuoteOriginally posted by ripit Quote
I gather the intensity can be reduced to safe levels if they use them in light shows and its approved to sweep people with them
Don't assume that. In Canada at least there are no rules about this and I've been to events where very powerful lasers were used. The people putting on light shows in bars don't know squat about laser safety. Lucky for them there often is smoke also, that helps protect the viewers.

QuoteOriginally posted by ripit Quote
now its just a matter of figuring out how to measure the intensity after the beam has been modified by whatever lenses
It's more complex than that, depends on the distance, the exposure duration, etc. As I wrote before, get a red one of class I, no more.
04-26-2013, 05:34 AM   #29
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Look at how efficiently a lazer at a rock show destroys a DSLR sensor in this thread:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/157971-caution-you...ned-laser.html

I can imagine that the human eye is softer and more delicate then a DSLR sensor.
04-26-2013, 07:49 AM   #30
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QuoteOriginally posted by bdery Quote
As I've written before, any Class I laser is safe, class II or more are dangerous.



Don't assume that. In Canada at least there are no rules about this and I've been to events where very powerful lasers were used. The people putting on light shows in bars don't know squat about laser safety. Lucky for them there often is smoke also, that helps protect the viewers.



It's more complex than that, depends on the distance, the exposure duration, etc. As I wrote before, get a red one of class I, no more.
Where would you even find a class 1 laser? Looking around the lowest I see are 1mw or <1mw which would make them class 2, but even those are generically labeled class 3a as they are also <5mw. It would seem the maximum that can be readily sold in in the US and at least some other countries is class 3 so I wonder if that is why they genrically label them as class 3a? I don't see anything that claims to be class 1 devices except for contained lasers such as a cd player (they are class 1 because they are contained, not because they are low power if I understand right).
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