Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

635nm vs 650nm

Joined
Jan 11, 2009
Messages
204
Points
0
I have a 200mw red 650nm red laser and want to purchace a 1 watt red 635nm laser diode can anyone on here tell me about what percentage brighter the 635nm will be over the 650nm even if the power output were the same. Thanks.
 





Low-Q

0
Joined
Dec 14, 2008
Messages
107
Points
0
I have a 200mw red 650nm red laser and want to purchace a 1 watt red 635nm laser diode can anyone on here tell me about what percentage brighter the 635nm will be over the 650nm even if the power output were the same. Thanks.
532nm seems to be 5 times brighter than 650nm. So that is 500%. Then the equation: (650 - 532) / 5 = 23,6.

650 - 23,6/2 = 638,2. 638,2 nm is 50% brighter than 650nm - or 1,5 times as bright.

638nm is pretty close to 635nm - should be almost the same.

This should not be a template for brightness index as the sensibility for colors isn't linear. It peaks at 532nm, but you'll have a rough clue.
 
Joined
Jun 28, 2007
Messages
3,443
Points
63
I used a 4 mW 635 nm and a 7 mW 658 nm pointer in a room full of fog, not much difference in the beam brightness at all, c/b the ratio will hold at greater output power. -Glenn
 
Joined
Mar 8, 2009
Messages
710
Points
0
The calculation is very rough, and also a 50% difference in brightness would only be detectable by direct comparison. This small difference might be masked by other differences, like beam diameter or intensity profile. 50% sounds like a lot, but considering the enormous sensitivity range of the human eye, it's minuscule.
 
Joined
Sep 12, 2007
Messages
9,399
Points
113
635 is five times brighter than 665nm, not 650. It is only twice as bright as 650.
 
Joined
Jun 14, 2009
Messages
880
Points
0
I think darkarmyofone is getting a 1 watt red for me in a kryton beast. Maybe that's where he's getting his, or that heurscience guy
 

Benm

0
Joined
Aug 16, 2007
Messages
7,896
Points
113
Cyparagorns figure sounds about right. The difference in visible intensity between 635 and the dvd-writer 655ish is in the order of 3 times. From 635 tot 532 should be another threefold increase for the same power level.
 
Joined
Sep 12, 2007
Messages
9,399
Points
113
According to my source, it is three times brighter than 660 (also a common red diode wavelength) and 2.3 times as bright as 655. 532 is 4.7 times as bright as 635. This is not for color mixing, just apparent brightness under photopic conditions.
 

Doc

0
Joined
Aug 14, 2008
Messages
35
Points
0
1W of 660nm = approx 42lm
1W of 635nm = approx 148lm

apparent brightness, so 3.5 times brighter.
 

HIMNL9

0
Joined
May 26, 2009
Messages
5,318
Points
0
^ this is the keyword ..... "apparent" .....

As example, i see my 220mW 808nm focused as a little red bar "apparently" 2 mW, with a dark red halo (also if it start to smoke non-white things in half second :p) ..... "apparently", none of my friends see the halo, and 2 of them, almost can't see the dim red bar ..... i always see green dots with a halo 10 times bigger than the point, if i don't point them on a black opaque surface, one of them see just the dot also on a cement wall, and start to see a halo only if i point a 50 mW on a white paper ..... with 405 nm at 100 mW, i see scattering halos also if i point it perfectly focused on opaque black plates (i see a halo made like a star with a lot of spikes, randomly moving, not just the usual shaded halo, probably my eyes accomodation get tricked from the UV part), where almost all my friends see just the dot with a fading halo ..... and one of the ones that is unable to see the red from the IR, can't fix the dot, also on a black object, for more than 5 or 6 seconds, then start to cross the eyes and tear, and have to stop to look .....

Also if is true that, basically, the peak sensitivity of the human eye is on the green region, perhaps that not all the peoples have the same identical sensibility curve about level and spectral range, also in absence of color blindness (daltonics) ..... so, how can we say this is better than that, or brighter, if anyone can see it differently ? .....

Just a thought .....
 
Joined
Nov 7, 2008
Messages
5,725
Points
0
Also if is true that, basically, the peak sensitivity of the human eye is on the green region, perhaps that not all the peoples have the same identical sensibility curve about level and spectral range, also in absence of color blindness (daltonics) ..... so, how can we say this is better than that, or brighter, if anyone can see it differently ? .....

Just a thought .....

People's sensitivity does vary from one individual to another, so the published curves represent an average sensitivity across the entire population. It serves as a guide to give us an idea of general human sensitivity. The variation is not very significant between individuals, so it's a fairly accurate representation.
 




Top