Would it be safe to look at 1.6W dot?

At daytime, 10m is ok for a short time.
During the night, I'd go with at least 25m.

paul1598419 said:

Some people are more sensitive to bright light than others. My daughter is one of those people, but I have no problem looking at the spot from my Sky Ray 1.7 watt or my 3 watt MS-SSW-II. And that is off a white wall at about 12 feet. It is no longer collimated or in anyway in Phase at all being reflected off of a rough surface, so the damage is more probably imagined. A blond or light colored retina is more sensitive to the brightness of the light. I never have had any damage, and I visit an ophthalmologist every year. She is very thorough and my retina shows no signs of damage.

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It really depends on your sensitive. I have no problem too looking at my 3.2W Zaser at 1-3 feet away. But my friends do so I buyed them glasses.

That is a quite short distance... No damage yet?

If you mean me, no not yet. Also tried burning something about 10-30cm in front of me, no damage to. Yay I have special eyes

I have a noob question. I just bought a 230wm green. Would I need saftey glasses for just fooling around? Ofcourse assuming not point in eye. But like just pointing at wall or trying to light a match?

I would recommend you safety glasses. 1. It's for yours and others safety and 2. You never k ow when you accidently hit some reflective objects. Also a 230mW Laser isn't for fooling around.

Cool thanks for the reply! You think black sunglaases would be ok and just be careful about where point the laser?

No not black sunglasses. Cheap safety glasses will do the job (12$ on ebay). No problem:beer:

Please don't buy those cheap glasses for a class 4 laser!
Buy Eagle pair glasses (40$) or buy lasershields (200$)
Please don't gamble your eyesight with those cheap glasses.
If you can't afford at least Eagle pair glasses then you shouldn't be able to afford a class 4 laser!

I have put a poll up to see what LPF Laser Safety Glasses wearing habits are. Just pop in there and pick the choice that fits you the best. Be honest as it is completely anonymous.

All the talk about laser safety makes me wonder whether people are as strict with themselves as they urge others to be.

HERE IS THE POLL THREAD

Didn't want a start a new thread, and tried searching to no avail, so I'll just ask it in this thread as it seems relevant and not too old.

I am curious how bad it is to view the dot on a diffuse surface and what distance would yield no eye damage (talking about 1+ watt 445nm here).

One test I was theorizing about was using a LPM to measure the mW that gets reflected off the surface back to the sensor. Because I would imagine the LPM would be able to give somebody a very accurate reading of how many mW are actually reaching the eyes at X distance.

For example, say you stand back 10 feet and shine a 3 watt 445nm laser at a diffuse non-reflective white wall. You hold the LPM at where your eyes would be and start measuring. The LPM measures 1mW.

So would this mean that by looking at the dot on the wall it would be the same as looking directly into a 1mW laser? Or is the damage less since the light coming into your eyes is off a diffuse surface, and thus not focused as if coming straight out of a laser?

I did some rough tests with my ~50mW lasers using a Coherent lasercheck set at the right wavelength, and the results were kind of surprising. For example a 50mW 445nm shining on a wall and the LPM held literally right next to the wall with a direct shot of the dot, registered on average 500uW to peaking a bit over 1 mW (depending on how I held it... this was a VERY rough test). However I cannot imagine putting my eye that close to the dot on a wall and not getting some kind of eye damage, as even 50mW is quite bright on a diffuse wall viewed from several feet and can still easily blind/damage with direct eye exposure or specular reflection.

So how valid is using a LPM to measure the mW being reflected back at the eyes from a diffuse surface?


EDIT: Oops, thought the thread was only about 10 days old... not two months old.

leukoplast, that is an interesting idea, I wonder though if it means anything. I wonder what results you would get from a power meter with the sensor exposed to direct sunlight, it might give a low reading yet you can't look directly at the sun, remember some of these lasers we're talking about will make a dot that is brighter than the sun so its too bright to look at it. I have looked at the dots from all of my lasers and I can immediately tell that they are mostly too bright to look directly at the dot. I think probably the power density at the dot may be more important than the total power.

Alan

I actually did measure the sun way back in the day when I got my lasercheck, and from what I remember it registered a few milliwatts... I think. It's dark now so I can't check but maybe I will during the day just for the heck of it.

But the thing is the lasercheck needs to be set for a specific wavelength, I can't set it to cover say, 400-800nm, it's either 400nm, 401nm, 402nm, 403nm etc etc. So the test is pretty inaccurate to what the sun is actually putting out since it doesn't measure full range.

Interesting subject though, thinking one way it seems like it would be really hard to hurt your eyes looking at the dot of a 1W+ 445nm at say 30 feet away, as it would likely measure only a few dozen microwatts in strength at that distance (if that)... yet one cannot deny the insane brightness of a well-focused laser dot (especially at super high-powers like these 445's), heck even a focused 4mW red looks quite bright if you stare at the dot on a wall several feet away.

I really hope these 445's, 462's, 520's, etc end up in a 5mW or less option one day. Cause the colors are just so awesome, yet being such high power makes them a bit hard to enjoy (well burning with goggles is still plenty of fun :evil, but any small hiccup without goggles and it's goodbye vision (party or wholly). Heck, even my ~65mW 445nm pen is plenty dangerous and can still destroy eyes in a split second. Absolutely beautiful color, but really can't "play" with it like one could with a <5mW pointer.

I've said it before and I'll say it again, I look at the dot from my 445nm 3 watt laser at a distance of 4 feet at an off white wall and it causes me no harm at all. I just finished a build for vortish that is a 445nm at 1500mW and I have been looking at it from about 4 feet and no problem at all. The dot is reflected off a non-polished surface and though the higher powers may get you to see the remnants of the light from the dot, it is by no means detrimental to your vision. No more than the flash from getting yourself photographed with the flash on. It just isn't focused any longer and therefore is perfectly okay to view.

I just focused my 2800mw laser at a flat beige painted wall 5' away. It's wasn't that bright. Now when I go out at night and hit the grass with it, a few feet way, and it seems like a welding arc!

A large part of that may be because your pupils in your eyes are dilated because it is dark outside and the flash of the light hitting them may be a bit much considering that your eyes have adjusted to the dark environment. I don't know about grass, but it may be more reflective than the wall for the 445nm wavelength.