Is this normal?

olympus mons · Dec 11, 2014

Hi laser peeps,
Today my new 405nm 400mW Power Rock arrived from O-like. Its a great looking host but I was surprised how dim the beam and dot is on this laser. i lit some Nag Champa incense to try and get a decent pic. Its barely visible. I don't have an LPM but was wondering if this sounds right.

I am still waiting on the 250mW 650nm Power Rock which was sent separately for some reason. When it arrives I will write a review for them both.
Thanks

NightExplorer96 · Dec 11, 2014

405nm is almost at the edge of our vision, so you are going to need a lot of power for it to look bright & see a beam

-Alex

TheGreaterWatt · Dec 11, 2014

Well in general that wavelength is less bright than, say a green at a comparable power.

That being said, for me, my 405nm is pretty visible. I can see the beam, however it is dim.

If you have concerns I would recommend sending it out to get metered by a reputable member, I know there is a thread around here somewhere with a list.

olympus mons · Dec 11, 2014

Tha Greenlander said:
405nm is almost at the edge of our vision, so you are going to need a lot of power for it to look bright & see a beam

-Alex

Thanks Alex. That's what I was figuring. I must have got a real powerful 405 off of eBay a couple weeks back because it was brighter than this power rock. Sadly I broke it while taking some pics of uv reactive dye in water. It fell off the table. :-( glad it was only $18.
Cheers

TheGreaterWatt said:
Well in general that wavelength is less bright than, say a green at a comparable power.

That being said, for me, my 405nm is pretty visible. I can see the beam, however it is dim.

If you have concerns I would recommend sending it out to get metered by a reputable member, I know there is a thread around here somewhere with a list.

That's a good idea. I am going to visit Flaminpyro after the holidays to have him help me do my first big build. A 1.4W 520 kryton so I will bring all my lasers and meter them if he doesn't mind me using his LPM.

NightExplorer96 · Dec 11, 2014

nwfreefly said:
Thanks Alex. That's what I was figuring. I must have got a real powerful 405 off of eBay a couple weeks back because it was brighter than this power rock. Sadly I broke it while taking some pics of uv reactive dye in water. It fell off the table. :-( glad it was only $18.
Cheers

No prob

I got one of those eBay 405nm pens & I can see the beam easily outside. Those things are crazy over-spec!

-Alex

Pi R Squared · Dec 11, 2014

My 590mW 405nm is barely visible in dim lighting although the dot is bright. At 400mW it should burn easy. Put it in that tripod on the table and point it at the wall about 10feet away, be sure it's focused and it should leave burn marks within less than 10 seconds. If not then it may be under powered, you need to have it tested with an LPM to be sure, but yes they are barely visible, and since it is at the limit of the visible spectrum it will be less visible to some and more to others.

Alan

TheGreaterWatt · Dec 11, 2014

Hmm, 400nW should be brighter than anything you get off eBay. I just noticed you live not to far from me, I could meet you somewhere? I have a power meter?

VisibleGreen · Dec 11, 2014

Just a little bit of fog and you'll see the beam

olympus mons · Dec 11, 2014

Pi R Squared said:
My 590mW 405nm is barely visible in dim lighting although the dot is bright. At 400mW it should burn easy. Put it in that tripod on the table and point it at the wall about 10feet away, be sure it's focused and it should leave burn marks within less than 10 seconds. If not then it may be under powered, you need to have it tested with an LPM to be sure, but yes they are barely visible, and since it is at the limit of the visible spectrum it will be less visible to some and more to others.
Alan

If thats the case then it must be way under spec because i held it inches from my palm for 4 seconds and it just tingled slightly! I used a black cd case and it did leave melt marks but only after 20 plus seconds. I knew 405's we not the brightest beam but this seemed much too dim to me. I am pretty new to lasers so wanted to double check.

TheGreaterWatt said:
Hmm, 400nW should be brighter than anything you get off eBay. I just noticed you live not to far from me, I could meet you somewhere? I have a power meter?

I would really appreciate that mate thank you. For one i want to be able to write an accurate review so people can decide if they wish to give O-Like their money and I also want mine back if this thing is very under spec. I'll pm you with my contact info tomorrow.
Thanks again. This is a great community.

TheGreaterWatt · Dec 11, 2014

nwfreefly said:
I would really appreciate that mate thank you. For one i want to be able to write an accurate review so people can decide if they wish to give O-Like their money and I also want mine back if this thing is very under spec. I'll pm you with my contact info tomorrow.
Thanks again. This is a great community.

Yeah no problem, I'd like to help if I can. Be a real shame if this turns out to be under-spec.

RYDorDIE278 · Dec 11, 2014

just noticed the O-like site says 340mW when you read lower in the page, thats suspicious when it says 400mW at the top,
Did you use a Fully charged quality Battery when you were experimenting? check battery with a DMM to rule that out if you can

Teej · Dec 11, 2014

Depending on your eyes, you may simply not be able to see 405 nm well regardless of power....

..and, to further confuse people, if its even more like 410 nm, it will LOOK a lot brighter because its now a wavelength that's visible to you.

So, a higher than spec wavelength will LOOK BRIGHTER and make you think its "more powerful" even if the wattage is down, etc.

So any combination of those factors can be at play.

Getting it metered is about the only way to know, for wavelengths that the eye just has too much trouble with.

mortuus · Dec 11, 2014

even a 500mW will look weak both the dot and beam but thats normal, it will look tho brighter when you take pics of it, cameras always seem to overexposure for some reason but in total darkness it should be somewhat visible.

GR3EN · Dec 12, 2014

My 1w 405nm doesn't appear that visible to me personally. As stated in complete dark yes the beam is visible and when a picture is taken it looks really solid. So I wouldn't be too concerned with the beam not being all that visible to you.

olympus mons · Dec 12, 2014

I hear what your all saying about visible beam not being so bright but would I be able to hold this inch from my hand for seconds without feeling anything if it was truly 340-400mW?

Shakenawake · Dec 12, 2014

depends how focused the spot is. is it the focal point that fails to burn you? if so, then i'd say yes, it's not the power it claims. I already suspect this if an ebay pen was brighter. 400mW of 405 should burn you for sure, esp the focal point. however, different skin will absorb light differently. If you are white, a 1W red laser will not readily burn you, but if you have darker skin... I guess red lasers are racist

you should probably just get it metered. there is a list as thegreaterwatt said. I'm not on it, but I do have a LPM and could do it as well.

Is this normal?

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