New Sanwu 150 mW Challenger2-Photos of LED Color-White Balance settings

[Pelagius]

I am in no way challenging Sanwu. It was marked 492 on the wrapping. Paul was thinking it looked more like 488 and I know he has compared many of these diodes.
But perception and photography are both fickle! I'd call this aquamarine.
So I set my Canon 5D MKIV on RAW, took the laser lens off and shined it on white paper-in indirect sunlight- took a picture of the paper by itself-then the led shined on the paper. I used Photoshop to White Balance- gave color temperature reading as between 6400 and 6300 K.
So here are shots of the paper- and the LED on the paper. The paper could be used for WB for anyone interested to make sure they are seeing what I am seeing.

If a mod wants to move this to my review thread-that's fine. My purpose is related to figuring out if it's really a 492 nm. I'm almost certain the only way is to buy a spectrophotometer measured 488 to compare-or a Laser Spectrophotometer.
Edit: on my screen the image is very close to what I see. Your monitor may vary-which is why I included the paper shot for White Balance/Color temperature adjustment
I'd also like a manufacturer to make a 200 mW+ version @ 493-495 nm- 1 Watt is acceptable

 

[BowtieGuy]

I'll bet one of the guys here that have a spectrometer would check that wavelength for you, then you'd know for sure. :yh:

 

[paul1598419]

Sure. I'd be happy to measure it for you. That is really the only way you will ever know for sure. If you are interested, send me a PM and I will give you my address. :yh:

 

[BowtieGuy]

Hey Paul, I figured you'd be the first to step in and volunteer to verify the wavelength of his 492nm? Sanwu. :yh:

 

[paul1598419]

Yeah, I'm always here to help anyone whenever I can. I need to send you a PM about something you might be able to do for me, Jeff. I will take care of that now. :yh:

 

[steve001]

I am in no way challenging Sanwu. It was marked 492 on the wrapping. Paul was thinking it looked more like 488 and I know he has compared many of these diodes.
But perception and photography are both fickle! I'd call this aquamarine.
So I set my Canon 5D MKIV on RAW, took the laser lens off and shined it on white paper-in indirect sunlight- took a picture of the paper by itself-then the led shined on the paper. I used Photoshop to White Balance- gave color temperature reading as between 6400 and 6300 K.
So here are shots of the paper- and the LED on the paper. The paper could be used for WB for anyone interested to make sure they are seeing what I am seeing.

If a mod wants to move this to my review thread-that's fine. My purpose is related to figuring out if it's really a 492 nm. I'm almost certain the only way is to buy a spectrophotometer measured 488 to compare-or a Laser Spectrophotometer.
Edit: on my screen the image is very close to what I see. Your monitor may vary-which is why I included the paper shot for White Balance/Color temperature adjustment
I'd also like a manufacturer to make a 200 mW+ version @ 493-495 nm- 1 Watt is acceptable

There's an accurate way for determining wavelength by using a diffraction grating and a laser of known wavelength. YouTube to see how.

 

[Pelagius]

Thanks Paul!

Sure. I'd be happy to measure it for you. That is really the only way you will ever know for sure. If you are interested, send me a PM and I will give you my address. :yh:

HEHE BowtieGuy

Hey Paul, I figured you'd be the first to step in and volunteer to verify the wavelength of his 492nm? Sanwu. :yh:

Yeah, I'm always here to help anyone whenever I can. I need to send you a PM about something you might be able to do for me, Jeff. I will take care of that now. :yh:

Steve! Thanks for reminding me. Something about a diffraction grating and measuring the distance between dots on the wall. I'll look into that!

There's an accurate way for determining wavelength by using a diffraction grating and a laser of known wavelength. YouTube to see how.

I'm pretty sure I'll keep it-either way.

 

[paul1598419]

If you already have a diffraction grating you can do this much easier than using a CD as a grating. But, your setup will be critical. So, measure the wavelengths of some HeNe and DPSS lasers to ensure the quality of your setup.

 

[Pelagius]

Hi Paul
I was looking on EBAY for diffraction gratings- they sell many- rated at 1000 lines/mm and above. Ideally, I am hoping for a handful of dots to measure-unless I am misunderstanding what the 1000 lines/mm rating means.
I did try reflecting off the back of a CD. Nice dots. Just have to get clams so I can hold it steady while I measure. I have a few DPSS (532 nm)- no HeNe lasers. An excuse to get a yellow? Yikes! 589 DPSS 50 mW $400! Maybe I'll wait for a price drop. I'd feel better with 2 reference measurements. I guess I'll do 5 independent 532 nm ,measurements to check my personal % SEM!

I see these from Dragon Lasers
https://www.dragonlasers.com/Laser-Beam-Splitters.html

If you already have a diffraction grating you can do this much easier than using a CD as a grating. But, your setup will be critical. So, measure the wavelengths of some HeNe and DPSS lasers to ensure the quality of your setup.

 

[steve001]

Hi Paul
I was looking on EBAY for diffraction gratings- they sell many- rated at 1000 lines/mm and above. Ideally, I am hoping for a handful of dots to measure-unless I am misunderstanding what the 1000 lines/mm rating means.
I did try reflecting off the back of a CD. Nice dots. Just have to get clams so I can hold it steady while I measure. I have a few DPSS (532 nm)- no HeNe lasers. An excuse to get a yellow? Yikes! 589 DPSS 50 mW $400! Maybe I'll wait for a price drop. I'd feel better with 2 reference measurements. I guess I'll do 5 independent 532 nm ,measurements to check my personal % SEM!

I see these from Dragon Lasers
https://www.dragonlasers.com/Laser-Beam-Splitters.html

The more lines per millimeter the greater precision will be gained. Another way i believe for greater still precision is to use a Youngs double slit. See here. https://youtu.be/uhNylYhg-YY

 

[paul1598419]

I believe the 1000 l/mm are for greater accuracy than precision. Precision is the ability to get the same result many times over using the same laser and setup. I bought a large sheet of 1000 l/mm that is 20 cm^2. I have had no use for it since getting my first spectrometer. I have cut sheets out of it and mailed them to members here that want to use a grating to measure wavelengths.