threshold (mW) visibility vs burning

[lasermanXYZ]

where is the mw threshold for green,when exceeded it only extends ur burning capabilities but visually(beam@night) stays the same. is there such a point? talking only pens and handhelds

 

[pschlosser]

I would imagine once it gets so bright, you go blind, that the threshold has been reached. (just kidding)

This is hard to pinpoint because as light gets brighter, your eyes (pupils) adjust accordingly.

There is a formula for this found in: IESNA Lighting Handbook, 9th Edition, New York, 2000.

Perceived Light (%) = 100 x SQRT(Measured Light (%)/100)

But I've read on this forum where people treat photonic brightness doubling in terms of electrical voltage and the 6dB rule, implying you must double the (measured) brightness of light twice before you see a perceived doubling in brightness.

Frankly, there are too many subjective variables to really nail this down.

 

[lasermanXYZ]

just to extend the "Laser pointer for astronomy: what to buy" thread. i want to keep it simple. and the problem is u cant really compare lasers by watching videos. cameras intend to "lie" the actual brightness. for me iam not into burning stuff but i want the highest brightness. so do i go for the simple 200mw pen or the handheld 400mw and up?

 

[Tmack]

I would say 250 mw but that's only opinion. I've noticed that any brighter one would only perceive two lasers at different powers as both " super freakin bright" instead of picking one being so much brighter than the other. I have had 100-200-300-400 mw 532. And once you pass 200 they are all really bright. I would hold up my 300 and 400 and ask people which they thought was brighter. I seldom got a straight answer. Most of the time they shielded their eyes and said " holy crap I don't know , their both killing me" lol
THIS IS ONLY MY EXPERIENCE . And others may have formulas for this but I'm going off my own tests. I would check my lpm and hold them up to the wall. At those powers (200-250 and above) one wold certainly need an lpm to determine which is brighter unless the power difference was veeeerryy substantial . Like more than double the power.

 

[pschlosser]

I can add that a 200mW seems to point as far as 500mW. Ive tested them side by side at night, star pointing. Yes, I can tell which is the 500mW, but to me they are really close and seem to project the beam the same distance.

 

[ultimatekaiser]

If they're next to each other it doesn't matter, they both reach farther than you can see and interpret. Even 5mW of 532 is visible to the eyes and appears to go on just as far. There are a lot of variables here. Ambient lighting will affect how you can see the laser, as well as the angle you're looking at the beam. atmospheric conditions also come into play, among other things. under the same conditions its generally accepted that it takes roughly 4x the power to get twice the relative brightness to the naked eye. Burning effects also vary with what you're trying to burn, how far away, divergence and filtering of the laser, interference...etc.

 

[pschlosser]

Bear in mind, for higher output powers, AAA batteries cannot provide enough current.

It's no accident many of our pointers use Lithium batteries, because they can dish out the current when needed.

 

[Tmack]

Laserbtb. 300mw for around $200 and quite small. And nice safety features.

 

[ultimatekaiser]

Battery current is true, but heat dissipation is critical. DPSS is very sensitive to temperature changes. A pen host cannot provide adequate heat dissipation. 200 mW of green ideally needs around a watt of pump energy. That's a lot of waste heat to deal with.

 

[Tmack]

How come 2 200mw 532 and not one big one? I've had the spartan 1w and the hulk Ultra 300mw. Both great.

 

[Tmack]

Like I said I have owned both hosts. The hulk host is more functional. Better heatsink with a lens shudder. The spartan is very sleek and pocket friendly, but has a smaller heatsink and a screw on lens protector instead of a twist closed function. For the green I would suggest the hulk. And I ordered batteries from battery junction in America so I can't speak k for dragons batteries. I can however say that the spartan 1w blue is a great laser. As well was the hulk Ultra. The only down sides about the spartan 1w is that it's not focus able and has an acrylic lens, so respect the duty cycle of three min. The hulk has a nice thin beam and very heavy quality design

 

[lasermanXYZ]

...i decided to give laserbtb a chance. btw thanks for the tip
they just have the better offers and i like those safety features on their lasers

but i will go for a blue first... but please answer me these 2 questions:

1) should i order with it the style1 googles for 30$, are they safe enough? or is there a better&cheaper dealer?

2) since i want to minimize damage risk and iam only out for brightness should i go for the 0,5w or 1w?

 

[pschlosser]

1) should i order with it the style1 googles for 30$, are they safe enough? or is there a better&cheaper dealer?

2) since i want to minimize damage risk and iam only out for brightness should i go for the 0,5w or 1w?

#1 If you like the style of goggles you see there, and don't have enough pairs, then order some. It isn't a bad price. The UVEX brand of goggle mentioned in my signature is among the best of those costing $10. Really, really nice quality ones can be over $100. The bottom line, they all protect your eyes satisfactorily.

#2 Both 500mW and 1000mW are bright enough you'll need to wear eye protection. They both can damage your eyes. But no matter what size you get, you'll want something bigger. buy the one you can afford.