More info on the S1 lens?

Thanks! found the auction. Looks like the China version of the G2. Hard to say with out any specs.

Just got mine today from TheJoker.. From what I can see, its definitely a difference. I've never used or seen the S1. Usually stick with the good ol' g2 3ele or g1<--- if I'm lucky. I'll try again to make it over to my fathers house to put them on the LPM. I keep saying that but never wind up going over! Oh, and Alaskan I ordered a 10X beam expander. Ill send you a pm with the listing and specs tomorrow.. Let me no what you think???

Aha, the amount the beam from the diode spreads before it hits the lens DOES reduce the divergence, if it has a FL of twice the distance of a G2, even though only a few mm, then the beam would be wider and thus reduce divergence, duh.... I'm using the same principle in one of my hosts by allowing the beam to spread for several inches before collimation with a large 2 inch diameter PCX lens.

Edit: Noob, I forgot which one we were talking about, pm me with the info

logsquared said:

Where are these s-1 lenses from?

FYI

the 3 element lenses are 8mm Fl the G2 are 4mm FL. Therefore the divergence of the 3 element is 1/2 that of the G2. This reduction in divergence is from the the longer Fl not from the beam getting clipped. The reduction in power is from the beam getting clipped and the extra air-glass interfaces the beam passe through.

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Basically we call any china lens an S1. Makes them easier to keep track of. We ran a GB a while ago for lenses and got them for like 3$ a piece. They came from O-like iirc. Also, aixiz sells these lenses as well for 8$. They all perform almost 100$ identical to the G lenses in every way, but are a fraction of the cost.

allright! so my lenses got here after a few months, and now i can measure the divergence in my red and violet laser.

oclaro 700mW 638nm 5.6mm diode.

600-800nm AR coated 3 element lens:
at aperture; 5-6mm
at 35 feet; 55mm.

S1 lens:
at aperture; 5-6mm
at 35 feet; 125mm...

as well as the terrible divergence, the laser also has more beam splash with the S1 lens, however it does not act like a flashlight with the beam splash since it is more concentrated around the spot. on to the next diode.

16X BDR-209 405nm, single mode.

400-500nm AR coated 3 element lens:

at aperature: 6mm
at 35 feet: 3-5mm (strange target shape, innermost dot is 2-3mm across and seems brightest)

S1 lens:

at aperture: 3-6mm, strange target shape.
at 35 feet: 6mm, and another gives 10mm. the other lens seems to be defective.

so, the S1 lens has almost 0 divergence with a single mode diode, however there is a bit of beam splash 20mm all around the dot at 35 feet. id say for any single mode, these are totally worth it.

I ordered some S1 from Israeli 5 weeks ago and they just shipped last week, I think they had a holiday over there or something.

Alaskan said:

With my S1 lenses used with a 450nm M140 laser diode I get some splash I don't get with the G2 lens, but because of their low price from a GB last year @ under $5 each, I have a bunch of them for general purpose lenses.

From what I've read regarding the three element lenses, the beam characteristics are much better and the divergence (reportedly, I have not confirmed this myself) is so much tighter I put one on a 1+ watt output 520nm laser diode and like it. If a three element lens can indeed reduce the divergence over a G2 lens, it would produce more power at a distance than the G2 lens, even though it has less loss. Has anyone verified a three element lens can produce a tighter divergence? Perhaps this isn't true as divergence is only reduced by having a larger diameter beam, right?

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The G2 has a 2.39mm rear focal length, the 3 element has a 5.3 mm rear focal length.
Now the 3 element does clip the edges of the highly divergent axis but that's the weak part anyway and at 15 feet your bar size will be half with a 3 element vs. a G2 and burning ability is greatly enhanced with the longer focal length.


These were taken at 14 feet and focused as well as could be ahead of taking the pics.
Both lasers are NDB7875's the slightly wider spot is the G7 the narrower is the 3 element, they are close at 14 feet but the G7 is slightly wider.
These were taken at 14 feet and focused as well as could be ahead of taking the pics.
Both lasers are NDB7875's the slightly wider spot is the G7 the narrower is the 3 element, they are close at 14 feet but the G7 is slightly wider.

In the top pic the 3 element is on the left and below in the middle pic the 3 element is on the right.


This is the same triangle cut piece as above only without the amber safety glasses in front of the camera and the lasers are off of course.


Now as for the G2, it's most useful up close and for knife edging before other optics, but at any real distance over 3 feet the G2 falls short in burning and spot size.
These pics are both NDB7875's well focused at 14 feet.
The smaller bar is the G7 and the wider bar is the G2.

This is a test at 14 feet.




The G7 starts to burn the plywood from 14 feet in just under 2 seconds, the G2 takes 3.5 - 4 seconds to start burning focused from 14 feet.
The 3 element starts to burn right at 2 seconds, just a fraction of a second behind the G7, hardly even noticible, actually the 3 element is still the winner for everything except making numbers on a power meter at 1 foot and knife edging before other optics.

Both lasers are NDB7875's

The splash in this clip may seem like the lasers are not at their tightest focus, but they are, the blond plywood reflects a lot around the bar and shows the artifacts.



The problem with the G7 is it focuses near the end of the 12mm housing's threads. 6-8mm rear focal length I have been told.
But it is not that much different than the 3 element as far as divergence.

The 3 element burns better at 14 feet than the G2 by a very noticeable amount because it produces about 4 times the energy density.

These multi mode diodes diverge like mad and one axis way faster than the other, at 100 feet with either lens it's a bright flashlight, IT CAN STILL DAMAGE EYES!!! But you are not going to do any burning at 100 feet with a 3 element or a G2.

Infinity focus the 3 element wins by a WIDE, pun intended, margin.

p.s. If anyone else want's to test G2 vs. anything I would love to see your results.
I am not attacking the G2, I am only presenting the fact man, just the facts man.

Alaskan said:

With my S1 lenses used with a 450nm M140 laser diode I get some splash I don't get with the G2 lens, but because of their low price from a GB last year @ under $5 each, I have a bunch of them for general purpose lenses.

From what I've read regarding the three element lenses, the beam characteristics are much better and the divergence (reportedly, I have not confirmed this myself) is so much tighter I put one on a 1+ watt output 520nm laser diode and like it. If a three element lens can indeed reduce the divergence over a G2 lens, it would produce more power at a distance than the G2 lens, even though it has less loss. Has anyone verified a three element lens can produce a tighter divergence? Perhaps this isn't true as divergence is only reduced by having a larger diameter beam, right?

Click to expand...

I also put a 3 element lens on my 1 watt 520, and like you, liked it. Little less power but the beam was much tighter.

micheal rosen said:

allright! so my lenses got here after a few months, and now i can measure the divergence in my red and violet laser.

oclaro 700mW 638nm 5.6mm diode.

600-800nm AR coated 3 element lens:
at aperture; 5-6mm
at 35 feet; 55mm.

S1 lens:
at aperture; 5-6mm
at 35 feet; 125mm...

as well as the terrible divergence, the laser also has more beam splash with the S1 lens, however it does not act like a flashlight with the beam splash since it is more concentrated around the spot. on to the next diode.

16X BDR-209 405nm, single mode.

400-500nm AR coated 3 element lens:

at aperature: 6mm
at 35 feet: 3-5mm (strange target shape, innermost dot is 2-3mm across and seems brightest)

S1 lens:

at aperture: 3-6mm, strange target shape.
at 35 feet: 6mm, and another gives 10mm. the other lens seems to be defective.

so, the S1 lens has almost 0 divergence with a single mode diode, however there is a bit of beam splash 20mm all around the dot at 35 feet. id say for any single mode, these are totally worth it.

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What is the result you want to accomplish using this S-1 lens?

steve001 said:

What is the result you want to accomplish using this S-1 lens?

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simply power increase. it has been tested so it does increase the power, what we didn't know was the effects of divergence.

micheal rosen said:

simply power increase. it has been tested so it does increase the power, what we didn't know was the effects of divergence.

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What is the focal length of this lens?

steve001 said:

What is the focal length of this lens?

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not exactly sure, i think its similar to the G2, but i really don't know. you should probably ask eitan (thejoker) he has a bunch of these he might be able to give you some info

micheal rosen said:

not exactly sure, i think its similar to the G2, but i really don't know. you should probably ask eitan (thejoker) he has a bunch of these he might be able to give you some info

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If it is within a couple of millimeters of the G2 lens then the divergence will be crappy. This is a single lens?

steve001 said:

If it is within a couple of millimeters of the G2 lens then the divergence will be crappy.

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yeah, i got the divergence data for a single mode and high power red multimode. it sure doesn't help divergence XD

The G7 has the long focal length. Compare G7 to 3 Element.
The S1 should be compared to the G2 as they are both single elements with a short focal length.
The G2 has a 2.39mm rear focal length.
I don't know what the S1 is but it should be close.

micheal rosen said:

yeah, i got the divergence data for a single mode and high power red multimode. it sure doesn't help divergence XD

Click to expand...

I see in post 15 it's 8mm. Just remember, to improve divergence the collimating lens has to have a long focal length and it should have a diameter that does not truncate the sides of the beam if that's what you want.

Some might not realize why a longer focal length reduces the divergence, the reason is the further the beam travels from the diode, the wider it gets and thus the fatter the beam and resulting reduced divergence, once collimated.