Best way to focus laser? and how eye safe is 300mw laser?

So how does one go about focusing a high powered laser? by high powered i mean anything you cant look at the dot of without eye protection.

I just purchased a 300mw red laser, this one to be precise Survival Laser R 660nm Parts Bundle w/Accessories & Rechargeable Battery

I also purchased a G2 lens.

I have it fully assembled and charged and it puts out 331mw according to my LPM. This was hard to measure since i cant see the dot with the eye protection so i aimed the tripod at the LPM with a 5mw laser and then swapped it for the big one and it seemed to work fine and keep its aim on the LPM.

However since i cant see the dot while wearing my eye protection, even if pointing at white paper from few inches away all i can see is very dim fuzzy ball of red light, not enough to be able to focus it well.

Should i just take a bunch of pictures with a quarter turn of the lens each pic and then i can tell what the best focus is and adjust it to that?

Im just going to assume taking my glasses off and looking at the dot without them and focusing it would be a bad idea right?

Also how safe is this laser? Right now im treating it like a lethal weapon.

For example without eye protection can I:

Look at the beam(if it has one, lol never look at it without eye protection yet)

Look at the dot from a distance on non reflective surface, if so what distance?

Also does anyone know if the G2 lens is getting more focused or less focused as you thread it into the head further?

--hmmm

maybe cheaper glasses will help you to see the actual dot-
when focusing.... it can be a two person job- one to watch the size of the dot (w/eye ware on) and another to change the focus to get the smallest dot- BUT if you have it focused and then change the distance the focus will likely change --

The glare/flare etc will make the dot look much larger that it actually is-- with glasses the glare should be gone leaving you the actual dot-- another thing- CAREFULLY put the dot on a black target - much of the glare will be gone- BUT keep in mind that black surfaces will heat up many times faster than a white target-so spray paint a brick w/flat black and have no worries.

hope this helps-------hak

hakzaw1 said:

--hmmm

maybe cheaper glasses will help you to see the actual dot-
when focusing.... it can be a two person job- one to watch the size of the dot (w/eye ware on) and another to change the focus to get the smallest dot- BUT if you have it focused and then change the distance the focus will likely change --

The glare/flare etc will make the dot look much larger that it actually is-- with glasses the glare should be gone leaving you the actual dot-- another thing- CAREFULLY put the dot on a black target - much of the glare will be gone- BUT keep in mind that black surfaces will heat up many times faster than a white target-so spray paint a brick w/flat black and have no worries.

hope this helps-------hak

Click to expand...

Yeah im using the Eagle Pairs that shipped with my laser, they do appear to be really good

I noticed the dot is frekkin huge in the pics i took thats why i made this post to ask for help. I took a pic and looked at it and in the pic the dot is easily 500 times larger than the dot on my 5mw laser. I was wondering if my lens was defective lol.

Yeah, you should be able to see the dot with your safety goggles on. I have those same pair (red blocking eagle pair) and can see my 650nm 235mW lasers dot fine. The only other way I can think of is like hak said, a matte black surface. It would pretty much have to metal, as anything else would like burn/melt, and that could be dangerous.

What lpm do you have? If it's TEC, like the radient x4, you may be able to use the heatsink away from the sensor. That's about as durable as anything, and flat black.

I sometimes just circle the dot on paper with a fine tip sharpies -wearing my eagles- then measure it(after I have it focused as small as possible- now i have digital calipers and they work great for dot/beam measuring-
same for beam size at apeture- just close it down until the laser just barely clears both 'jaws' of the caliper- that should be the size there- some are not round(like 445) so you need to meausure the shortest and the longest both-
but best focus at any distance is very hard to do alone..

So i got my laser focused, im not sure if i was smart in my method or not but here is what i did.

I got a box, triple walled thick cardboard, box was 1'x1'x4' deep, so a tall rectangle standing 4' high with a 1'x1' opening. I then pointed my laser down into the middle of this box so that the dot was in the bottom of the box and not visable to me unless i jumped 2-3 feet into the air, so i considered that safe(i wasnt wearing eye protection so needed dot to be not visable to me). I held the laser 12" from top of box pointed into it so clearly visable was the first 12" of laser beam(which i have been told is safe to view with no glasses).

I then adjusted lens so that laser beam at 12" right as it was entering box was as thin as possible, this was easy to do with the contrast of beam entering box i was very easaly able to dial in the lens. I was trying to focus to thin as possible at 12" distance. This took a while as lens was loose and kept going off adjustment and when i started was very far screwed in and beam was VERY wide(3cm or so) at 12" when i started. I did not realize that to get to a tight spot the lens had to be unscrewed almost to point of falling out end of laser. I dont know if this is just poor design of G2 lens or axiz modual theads/distance to diode or what im too much of a newb to know if its normal to need it almost falling out to get it focused.

I have some lens springs on order they should help the lens keep focus, i found teflon tape to not be enough even with 3-4 wraps.

Also after i focused it i put my goggle on and was able to, at 12" distance, burn paper(after i put black marker on it) and light matches(again with black marker on them) and melt black plastic. So i believe my focusing was succesful.