My new g8 lens

[thedoc8]

I bought off dtr laser a 20mm copper module and a g8 lens for it. The 20mm copper one came with a lens that screwed into the copper. I had to turn the threaded part almost all the way in to get it to focus about 3 to 5 feet. Also had to remove the focus ring to do that. Seemed the threaded part was not long enough, but I figured it was just a chepo lens. I then ordered from dtr the g8 lens, the threaded part was twice the length of the other one and had threads inside also.

My question is, setting this rig on my desk and adjusting for a nice pinpoint at 12 inches, the threaded part is way out of the copper head even with the focus ring on. Is this normal, does the lens down in the threaded part supposed to be adjusted inside or left alone where it was when I got it. I did not know if it threads in and out of the threaded part or is glued in. This was just because the first lens was not like this at all. Also can you glue the focus ring on, cause when you turn cw it does ok, but turning ccw it just comes off. Thanks for any enlightenment, hope some of this makes sence. I tried to find answers, but these are strange question.

 

[Coonie]

Yeah it's normal for the g8. I think because it's a long focal length lens but I'm probably getting that wrong. Someone correct me if I am wrong on that.
They definitely could use a custom spacer to center the lens in the housing.

 

[thedoc8]

Yeah it's normal for the g8. I think because it's a long focal length lens but I'm probably getting that wrong. Someone correct me if I am wrong on that.
They definitely could use a custom spacer to center the lens in the housing.

Thanks, I just don't know the tiny details yet.

 

[Snecho]

Suggest moving this thread to "Optics"

 

[GSS]

If i'm understanding correct I believe the lens that came with DTR's module is plastic. He usually puts a plastic lens in for dust protection or any protection from something getting in and hitting the diode.
The plastic lens is just that, plastic with a short plastic threaded barrel. Now if you ordered the 20mm module you have to be using a more powerful diode and i'm surprised the lens hasn't melted yet.
I don't have or ever used a G8 so I can't say about focal length and how far the barrel might stick out.
Are you sure you have in the right way and not back words?
I also think you are asking about the lens barrel threaded inside's and adjusting it? The inner barrel is threaded because it uses a threaded ring to hold the lens in tight. It shouldn't need to be adjusted or played with at all unless for some strange reason it loosened. That is what I know about the G2's and 2 element lenses but assuming its the same setup with the G8.
Now going back to the plastic lens, that is glued and fixed but I wouldn't use it because it will melt.

Edit: You need to put the focus ring on the lens barrel snug "finger tight" preferably before you screw it into the module, this will keep it from spinning and help focus the laser CW and CCW.

 

[RedCowboy]

I bought off dtr laser a 20mm copper module and a g8 lens for it. The 20mm copper one came with a lens that screwed into the copper. I had to turn the threaded part almost all the way in to get it to focus about 3 to 5 feet. Also had to remove the focus ring to do that. Seemed the threaded part was not long enough, but I figured it was just a chepo lens. I then ordered from dtr the g8 lens, the threaded part was twice the length of the other one and had threads inside also.

My question is, setting this rig on my desk and adjusting for a nice pinpoint at 12 inches, the threaded part is way out of the copper head even with the focus ring on. Is this normal, does the lens down in the threaded part supposed to be adjusted inside or left alone where it was when I got it. I did not know if it threads in and out of the threaded part or is glued in. This was just because the first lens was not like this at all. Also can you glue the focus ring on, cause when you turn cw it does ok, but turning ccw it just comes off. Thanks for any enlightenment, hope some of this makes sence. I tried to find answers, but these are strange question.

G2 and G8 are both AR coated for visible wavelengths ( 400-700nm ) IINM and are highly efficient single elements, both are more efficient than the 3E which is usually coated for R, G or B only, much less efficient and prone to clipping.

For focusing to a point at 12 inches you should be using a G2

A longer FL lens will focus further out.

The focus ring ( thumb ring ) simply screws on snug, no need for any glue.

 

[thedoc8]

If i'm understanding correct I believe the lens that came with DTR's module is plastic. He usually puts a plastic lens in for dust protection or any protection from something getting in and hitting the diode.
The plastic lens is just that, plastic with a short plastic threaded barrel. Now if you ordered the 20mm module you have to be using a more powerful diode and i'm surprised the lens hasn't melted yet.
I don't have or ever used a G8 so I can't say about focal length and how far the barrel might stick out.
Are you sure you have in the right way and not back words?
I also think you are asking about the lens barrel threaded inside's and adjusting it? The inner barrel is threaded because it uses a threaded ring to hold the lens in tight. It shouldn't need to be adjusted or played with at all unless for some strange reason it loosened. That is what I know about the G2's and 2 element lenses but assuming its the same setup with the G8.
Now going back to the plastic lens, that is glued and fixed but I wouldn't use it because it will melt.

Edit: You need to put the focus ring on the lens barrel snug "finger tight" preferably before you screw it into the module, this will keep it from spinning and help focus the laser CW and CCW.

Thanks very much for the education, don't think it was backwards cause of the little notches for turning. Everything is good just needed to know it was right. Thanks again.

 

[thedoc8]

G2 and G8 are both AR coated for visible wavelengths ( 400-700nm ) IINM and are highly efficient single elements, both are more efficient than the 3E which is usually coated for R, G or B only, much less efficient and prone to clipping.

For focusing to a point at 12 inches you should be using a G2

A longer FL lens will focus further out.

The focus ring ( thumb ring ) simply screws on snug, no need for any glue.

Thank you, the 12 inches was just a test. Most of my beaming is in trees and the sky. Thank you for the mind expansion. I will try the g8 outside tonight.