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



DTR G8 lens

CDBEAM777

Well-known member
Joined
Feb 25, 2010
Messages
1,645
Points
113
I have not measured....gotta do so....BUT....the NDG7475 starts out with somewhat reduced divergence from the cleavage plane.....so....when the G8 is added....based on my trials...the beam is fairly tight....AND...NO BOX GHOST/ARTIFACT.
Sorry....not scientific...but....I am a typically not happy with anything but a tight beam....and IMNSHO....the NDG7475 + G8 is a wining combo. Will do a quick divergence test shortly.

CDB
 



Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,967
Points
113
Thanks Bob, appreciate your taking the time to do that. I'm going to guess 1.5 mRad :p maybe a bit higher.
 

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,711
Points
113
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

Oh someone is late checking back in on this thread.🤪
Pretty sure I know exactly which ones you mean. Last chance I gave the original company which was being used for the thread that collectively designed. They were not a good company. I just was looking at that thread a few days ago. Will find the link. Something was wrong with the tap on that batch and the pitch got slightly skewed caused the M9 brass barrels of the 405-G-2 I had at the time. Fixed them but wss a real pain. Those were I think made in 2014 or abouts.


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.

Yea guess I did not explain well that was what I was going for. Panny lens element itself is 8.4mm diameter and say the lip be made so over 8mm opening . An option could be to just include the adapter so using the Legacy M9. Still got some time to figure this on 20mm and 25mm if I want to add this as an option

I also have access to new panny blocks which have been phased out in the newer units so got a chance to snag quite a few of these lenses.


Eh, G really means nothing, just a label. I once readhere 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, 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.

Ha looks like when I got those DTR-G-8's I meshed up as see this for the correct sizing for the lens barrel. Need to get those updated today.

\
 
Last edited:

absolute

Member
Joined
Jan 5, 2016
Messages
53
Points
18
The G8 lenses I got from DTR have a 7mm aperture on the input side of the barrel, I measured it with calipers.
So if you have a 6.6mm wide beam at the contact point of the lens there would be no clipping.


Edit: oops, DTR himself just provided measurements, I must've remembered wrong then 😅
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,967
Points
113
Many lens manufacturers don't allow more than about 80-90% of the lens diameter for a clear aperture specification. I have no idea if that general rule holds true for these tiny collimators or if it really matters for our pointers as these are just toys for us :)
 
Last edited:

steve001

Well-known member
Joined
Jun 3, 2007
Messages
2,485
Points
113
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.
Yeah I know the "G" means nothing. I was merely curious why this type lens appears to be the only option (stated by most). You're right that you'll need parts machined.
 
Last edited:

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,967
Points
113
From what I can see, we are limited to the size of the barrels used with Axiz and DTR diode mounts, but that also hinges on the size of the lenses we can get, if there were larger aspheric lenses readily available at low cost, I would hope a larger diameter barrel would be offered for lower divergence, but right now the only diodes which I would use one for are the NUBM44 and perhaps the NDG7475, if you don't like the divergence you get using a 6.3 mm diameter lens. I don't, won't own one without either corrective optics, or a spherical beam expander. Of course, you could just have a custom pointer made with what ever diameter lens you want to use and not use a lens barrel, I've done that.
 

Coonie

Active member
Joined
Jan 12, 2018
Messages
313
Points
43
Two questions I have about these lenses as I bought two earlier this month. 1. Can these lenses be used with cylindrical corrective optics? and 2. Is it possible to mount the actual lens in the center of the retainer so that it won't stick out as much?
 

RedCowboy

Well-known member
Joined
Jul 10, 2015
Messages
10,028
Points
113
Two questions I have about these lenses as I bought two earlier this month. 1. Can these lenses be used with cylindrical corrective optics? and 2. Is it possible to mount the actual lens in the center of the retainer so that it won't stick out as much?

If you made a screw in seat that could work or possibly just a hollow spacer.
 

Coonie

Active member
Joined
Jan 12, 2018
Messages
313
Points
43
If you made a screw in seat that could work or possibly just a hollow spacer.

Ah sorry man lpf didn't give me a notification for some reason. Yeah a hollow spacer would do it but not sure how to make one. There's got to be hollow metal rods or plastic tubing out there that would work. Thanks man I'll shop around.
 

RedCowboy

Well-known member
Joined
Jul 10, 2015
Messages
10,028
Points
113
Ah sorry man lpf didn't give me a notification for some reason. Yeah a hollow spacer would do it but not sure how to make one. There's got to be hollow metal rods or plastic tubing out there that would work. Thanks man I'll shop around.


 

skijohn

Member
Joined
Sep 8, 2018
Messages
32
Points
8
I could be wrong but the G-8, when used with a NUBM44-V2 diode and its degree output angle from the large axis of that diode, seems to be clipping due to the larger distance away from the diode than a G-2?
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,967
Points
113
RedCowBoy is the man to ask on this question, but I believe he did report there is some clipping like that.
 

RedCowboy

Well-known member
Joined
Jul 10, 2015
Messages
10,028
Points
113
I could be wrong but the G-8, when used with a NUBM44-V2 diode and its degree output angle from the large axis of that diode, seems to be clipping due to the larger distance away from the diode than a G-2?

Yes the divergence of the 44 is quite aggressive and it get's clipped at the edges by most lenses even the 3 element, that's just the nature of the beast, still the G8 passes more power than the 3 element likley due to internal clipping, if you want to catch all of the nubm44's output use the G2, but there is a trade off in far field beam width, if working up close such as on your desktop the G2 is great but far field your beam will be much wider unless you employ additional optics, so choose based on your need/taste.
 
Last edited:

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,967
Points
113
Appears the first photo shows the beam focused down to a spot, the second one either at infinity or wider than that. I would not like an artifact when adjusted to infinity, but if just focused down to a spot, not so bad. I have not worked with this diode enough or with that lens using it to be able to comment more.
 




Top