Few questions on beam visibility(day time, night time) and eye safety?

[gen6]

Hi guys!!! I read the guides but I still have few questions...

I want to buy a green laser, as I read the posts, I chose rayfoss or o-like.

What I aim for is maximum beam visibility under all conditions and at the same time no need for safety glasses. My bravest guess would be that I need 30mw but I don't know if I'm right.

Now here are my questions that may change my requirements and my choice. Questions are for Eye Safety and Beam Visibility, all of the questions refer to all the different lasers , starting from 5mw, 30mw, 50mw, 100mw, 200mw.

Eye Safety: (for all types 5mw, 30mw, 50mw, 100 mw etc)

1.What is the eventual harm when pointed straight in the eye for 1-2 seconds and does distance matter, if pointed in the eye from 1 meter or from 150 meters, 1 km?

2.What is the eventual harm when looking the dot itself from various distances(10cm, 2 meters, 50 meters) , let's say the laser is pointed at a white wall.

3.Is there any possible harm when looking the beam itself in no matter what conditions?

4. Is the damaging effect reduced significantly if the laser is reflected from a mirror and then hits the eye?

Beam Visibility (for all types 5mw, 30mw, 50mw, 100 mw etc)

1. How much is the visibility of the beam during sunny day time in a clear day?

2. How much is the visibility of the beam during night time? (for all types )

3. How much is the visibility of the beam in a well lit room?

4. How far the beam goes in day time, night time ? (let's say in night time 5mw laser, how far will it go compared to 30mw and 100mw? , In day time how far will 100mw go, if it's visible at all?

Does the point get bigger with distance, for example 1 meter small point, 500 meters one big fat point or it stays the same? (for all lasers)

Thing is that I don't want to wear safety glasses when I'm outside...for example at night time and I just shoot the laser in front of my feet while walking, if 100mw can do damage just by looking the point itself, that's very inconvenient. Also if I buy 100mw laser I don't want accidentally damaging someone's eyes by accidentally pointing at him from about let's say 800 meters, is that possible? I just want to know what are the potential risks of the more powerful lasers while being used outside of home because I'm mostly going to use the laser outside, not inside my house. I guess nobody wears protective glasses outside, right?:evil:

Guys, thank you in advance for your answers and I'll thank you after that as well!

 

[david1235102]

first of all, Welcome to LPF!
most, if not all of your questions have been answered on here before. just use the search bar and read read read.
also, no laser will have a visible beam in daylight. any laser over 5mW has the potential to cause eye damage.
NEVER LOOK INTO THE LASER OR SHINE IT IN YOUR OR SOMEONE ELSE'S EYES
if it hits a mirror and is reflected into your eye, it will still do damage. you should get safety glasses to use if you are indoors.
all lasers get larger the further they go; this is called divergence. the smaller the divergence, the better.
i tried to answer some of your questions but i know i didn't answer all of them (sorry if i was sort of random in my thought process). i can vouch for o-like and rayfoss as good companies too. the main thing it sounds like is that you need to do a lot of research on here because you'll find what you're looking for + much much more useful information.
here are some threads you will find useful:
http://laserpointerforums.com/f45/guide-buying-your-first-green-laser-30608.html
http://laserpointerforums.com/f45/some-faqs-about-green-dpss-lasers-30682.html

also look through threads made by newer members such as yourself: they have the same questions and there may be answers in those threads too

so yeah... hope some of this helps

 

[chipdouglas]

Eye Safety: (for all types 5mw, 30mw, 50mw, 100 mw etc)

1.What is the eventual harm when pointed straight in the eye for 1-2 seconds and does distance matter, if pointed in the eye from 1 meter or from 150 meters, 1 km?

blindness. it's not worth testing to find out safe levels

2.What is the eventual harm when looking the dot itself from various distances(10cm, 2 meters, 50 meters) , let's say the laser is pointed at a white wall.

blindness. it's not worth testing to find out safe levels

3.Is there any possible harm when looking the beam itself in no matter what conditions?

no problems here, but always be safety conscious. accidents DO happen.

4. Is the damaging effect reduced significantly if the laser is reflected from a mirror and then hits the eye?

no. mirrors are highly reflecte like 90+%

Beam Visibility (for all types 5mw, 30mw, 50mw, 100 mw etc)

1. How much is the visibility of the beam during sunny day time in a clear day?

not going to happen

2. How much is the visibility of the beam during night time? (for all types )

the closer you get to green 532nm, the better the visibility. so the further away you get the more power you need.

3. How much is the visibility of the beam in a well lit room?

not good at all

4. How far the beam goes in day time, night time ? (let's say in night time 5mw laser, how far will it go compared to 30mw and 100mw? , In day time how far will 100mw go, if it's visible at all?

don't understand the question

Does the point get bigger with distance, for example 1 meter small point, 500 meters one big fat point or it stays the same? (for all lasers)

yes the dot gets bigger even though it looks like it is staying the same size. This is called divergence.

michael.

 

[gen6]

Thank you for the answers guys!

Alright, may be I'll reduce my questions to just four...

if I buy 30mw laser, would it harm somebody's eyes if one is hit from let's say 100 meters for 1-2 seconds straight in the eye?

Again for 30mw laser, would it damage my eyes somehow if I look at the dot while pointing at a white wall, no matter what distance?

At night time, is there noticeable difference between the beam of 5mw, 20mw, 30 mw laser ?

How much will the batteries last for this 30mw one http://rayfoss.com/productn.asp?ArticleID=3 compared to this one http://rayfoss.com/productn.asp?ArticleID=9 ? Is it worth to buy the latter just because of the different batteries, because I don't need water resistance ?

And just a final question, sorry for that....
Rayfoss http://rayfoss.com/productn.asp?ArticleID=9 or Romisen L-B030 http://www.priceangels.com/30mW_Romisen_L-B030_Green_Laser_with_GITD_Tail__CR123A__p2692.html , same size, same battery, waterproof....which one to buy ? (and I also need to buy a battery charger, right? )

 

[chipdouglas]

Thank you for the answers guys!

Alright, may be I'll reduce my questions to just four...

if I buy 30mw laser, would it harm somebody's eyes if one is hit from let's say 100 meters for 1-2 seconds straight in the eye?

Again for 30mw laser, would it damage my eyes somehow if I look at the dot while pointing at a white wall, no matter what distance?

At night time, is there noticeable difference between the beam of 5mw, 20mw, 30 mw laser ?

How much will the batteries last for this 30mw one http://rayfoss.com/productn.asp?ArticleID=3 compared to this one http://rayfoss.com/productn.asp?ArticleID=9 ? Is it worth to buy the latter just because of the different batteries, because I don't need water resistance ?

And just a final question, sorry for that....
Rayfoss http://rayfoss.com/productn.asp?ArticleID=9 or Romisen L-B030 30mW Romisen L-B030 Green Laser with GITD Tail (CR123A) $29.44 Free Shipping , same size, same battery, waterproof....which one to buy ? (and I also need to buy a battery charger, right? )

the answer you should only care about is that a laser WILL cause eye damage no matter what...

2... we would have to know the current draw of your laser to estimate a battery life.

 

[david1235102]

I would personally go for the 30mW one.
as for pointing it at a white wall, it depends on the brightness in the room and how far away it is. It will cause you to see spots though (if it is dark) and just don't do it.
for brightness: generally it is twice the brightness for 4 times the power. so a true 20mW of green will be twice as bright as a true 5mW of green.
as for safety, listen to chipdouglas.
never point a laser at someone, any vehicle, or airplane. if you want to find out if it does damage at that distance, do it yourself. just don't come crying back here or to anyone when you are blinded. If you are actually irresponsible enough to try it, then you shouldn't have the laser.
last thing; go for a laser that runs on li-ion rechargeable batteries. they'll save you money over time and they will have better run times than primaries.