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DTR G8 lens

RedCowboy

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I had Rich/Lifetime17 make some threaded adaptors for me and I have found them to be useful for many purposes, granted a longer copper module would work well for the G7 and G8 lenses but these also do well if you want to lock down an infinity focus.

65136


---edit---
Also these 24x30mm aluminum housings have a long threaded portion for the M9*0.5 lens barrels if you want to set the focus but likely won't accommodate a thumb wheel on the standard length lens barrel although I have not tested a G8 at it's FL in one yet.

 
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Spoomples

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Odd question: Are these always darkly colored, or do they sometimes have the standard brass look?
 

LASER66

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G2

Here is the lens china ripped off and became G2.

You can see the FL = 4.02mm. Also, WD = BFL

You should go back and edit your posts so people in the future don't get the wrong info.



I too have noticed the 3E are not all the same. The half threads always seem better regardless of where i bought them.
WOW, thanks for the using the term Ripped Off. Yeal, copied and/ or made up the drawings.
 

LASER66

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All the talk about G-2... Is it the fake G-2 or Genuine 405-G-2 ? Likely some of the comparisons of older builds may be the fake / more recent G-2's- uncoated. How does it compare to the Genuine 405-G-2? Does anyone have one they know are real and can test/ compare? DTR? Real 405-G-2's have a slightly modified, multi- layer A coating shifted down for better performance at 405nm. It was developed for original 405nm Nichia diodes. We used that lens to match up nicely with the $2000 Sanyo diodes at 5mW, yes about $1800 wholesale. That was just prior to LPF tests of the 405's offered in the PS3's and later sleds with 3 wavelengths- oh, those were the days!
 

Hemlock_Mike

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Jordon -- I got a G8 lens some time back. The lens would not fit your Cu housing for my blue Phaser gun.
Today, I put it in a 2W blue pointer and WOW does it make a difference.
I will buy another if it fits the Cu heat sink in my Phaser. Can this G8 glass be transferred to a different housing?
The glass works great but would not fit my Cu heatsink.
Thanks -- Mike
 

paul1598419

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Huh. All mine fit Jordan's modules, but they do sit far out of the module because of the longer FL and the longer lens housing.
 

Alaskan

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When you say they don't fit in his modules, do you mean there aren't enough threads left over for your preference? If so, I can agree with that, but they do fit in mine.
 

DTR

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Jordon -- I got a G8 lens some time back. The lens would not fit your Cu housing for my blue Phaser gun.
Today, I put it in a 2W blue pointer and WOW does it make a difference.
I will buy another if it fits the Cu heat sink in my Phaser. Can this G8 glass be transferred to a different housing?
The glass works great but would not fit my Cu heatsink.
Thanks -- Mike
Whats up Mike.🍺
That is strange. When did you get that module and what size diode is in there?
Glad you like it with the 2W blue. Great pass efficiency while giving a lower divergence than the other singe element G variants is great. Plus the best feature they sport is getting rid of the box reflection artificial in the output on the high power mulitmode diodes . Not sure why it does not remove it completely on some of the singe mode diodes that have that artifact in the output though.

Huh. All mine fit Jordan's modules, but they do sit far out of the module because of the longer FL and the longer lens housing.
When you say they don't fit in his modules, do you mean there aren't enough threads left over for your preference? If so, I can agree with that, but they do fit in mine.
Two possibilities come to mind. Maybe one of the early modules revisions. The first batches had the diode sitting a bit higher in the threaded pocket. Also there were some 3.8mm ones made real short.

The other possibility is that the diode was over-pressed with too much force.

Either way any options for changing how the lens element sits in the barrel would increase clipping causing more power loss. The next batch of modules will resolve with a slightly deeper pocket. The 20mm and 25mm will also have a deeper pocket plus looking for some feedback on an idea I am considering of changing to a M11X0.5mm threading for the lens and making the M11X0.5mm lens barrels with a inner M9 threading giving legacy support for the M9X0.5mm lenses.:unsure:
 

paul1598419

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Hi, Jordan. Unless the lens diameter is increased along with the housing diameter I can't see this as an improvement. There are just too many lens housings that are 9 mm in diameter. It would necessitate buying all new housings to fit the new modules, IMO.
 

Hemlock_Mike

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Jordon --
That lens module simply would not go into the heat sink. It acted like it was cross threading. Other lens
assemblies fit right in and the G8 lens fit my other heat sinks.
I noticed that the lens is farther from the diode in my 2 watt but it has plenty of threads and it works.
Thanks guys -- Mike
 

Lifetime17

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Hi,
Mike if it seems to be feeling like cross threading the only way to prove that is presss out the diode and get a M9x0.5 bottoming tap. Then try the lens these taps are common and easy to obtain. Try a different lens barrel to prove what thread is using the issue, Lens barrel or module thread.

Rich:)
 

Alaskan

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I'm considering the use of the G8 lens with the NDG7475 520 nm green laser diode and have been searching this thread for the divergence of this diode with this lens. Maybe I didn't look close enough, but I didn't find the information in direct mRad numbers, I can derive it though, but something more important has come to light and that is the min-max divergence of the NDG7475 can possibly produce clipping at 8 mm FL.

My calculations are showing for the typical 46 degree output angle from the large axis of the NDG7475 diode at 8 mm focal length the beam should be about 6.6 mm wide, so at that amount of clipping I wouldn't be terribly concerned, but at the maximum possible raw divergence output from this diode of 55 degrees, the clipping could be as much as about 25%. From this I guess the question is; how likely am I to get a NDG7475 with a 55 degree wide output?

These numbers derived using this link: http://www.1728.org/angsize.htm



Maybe the G8 lens is a bit larger diameter than the G2, and thus we don't suffer clipping? It could be slightly larger if the holder is slightly thinner, but looking at the photo of the input side, the aperture appears slightly smaller than that of a G2 lens to me, regardless of the lens diameter.



Above G8



Above G2

Maybe they are identical on the input side, but even then, I would expect some of the NDG7475 laser diodes which have a larger than typical divergences up to 55 degrees would have substantial clipping. Are my numbers or assumptions incorrect? Maybe this won't happen with the min-max divergence range of the NDG7475?
 
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steve001

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I'm considering the use of the G8 lens with the NDG7475 520 nm green laser diode and have been searching this thread for the divergence of this diode with this lens. Maybe I didn't look close enough, but I didn't find the information in direct mRad numbers, I can derive it though, but something more important has come to light and that is the min-max divergence of the NDG7475 can possibly produce clipping at 8 mm FL.

My calculations are showing for the typical 46 degree output angle from the large axis of the NDG7475 diode at 8 mm focal length the beam should be about 6.6 mm wide, so at that amount of clipping I wouldn't be terribly concerned, but at the maximum possible raw divergence output from this diode of 55 degrees, the clipping could be as much as about 25%. From this I guess the question is; how likely am I to get a NDG7475 with a 55 degree wide output?

These numbers derived using this link: http://www.1728.org/angsize.htm



Maybe the G8 lens is a bit larger diameter than the G2, and thus we don't suffer clipping? It could be slightly larger if the holder is slightly thinner, but looking at the photo of the input side, the aperture appears slightly smaller than that of a G2 lens to me, regardless of the lens diameter.



Above G8



Above G2

Maybe they are identical on the input side, but even then, I would expect some of the NDG7475 laser diodes which have a larger than typical divergences up to 55 degrees would have substantial clipping. Are my numbers or assumptions incorrect? Maybe this won't happen with the min-max divergence range of the NDG7475?
Are G brand optics the only option?
 

Alaskan

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Eh, G really means nothing, just a label. I once read where it started, but someone will need to refresh my memory now. I have some 15 mm diameter PCX lenses I would like to get an adapter machined with a cone to thread into a DTR laser diode mount which might be good for single mode laser diodes, but so far, only being discussed with a machinist. A PCX lens is good, but an aspherical is better, I just want a lens with a longer FL (edit: for even lower divergence), but as you can see from the G8, for the NDG7475 it appears 8 mm is about as long as we can go with the lens barrel diameter we are using.
 
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