G2 lens help needed.

[Nute]

Hi, I searched the forums, and did not entirely find the answers to my question. So, here we go. I just recently purchased a G2 lens from Aixiz for my 445nm A140 build, and I can't seem to get it to focus at all. What I mean by that is my standard focusing ring is not able to be screwed onto the lens housing, since when I try focusing the beam my focus ring bottoms out on my heatsink while only being threaded on 2 threads. Second when I try focusing the beam without a focusing ring, the lens in almost all the way inside the module. I am attempting to set the beam to infinity using a garage located 200 yards away, however the best I can get the spot is about 12 inches. When I point it into the EMPTY night sky and try to set it to infinity, it always looks to be expanding with distance even at its best focus. I have it installed with the slots out, and the lens closest to the diode window rather than upside down. I haven't seen one with a lens barrel this short or had as much trouble focusing, as it seems to be very temperamental with very minor adjustments. Please help me if you can. I really like my 3 element, but would like to experience the G2 bliss you all do. Thanks in advance guys.

-Nute

Also, The beam looks to be thinner, than my 3 element no matter how it is focused. I thought the G2 would to the complete opposite.

 

[Shakenawake]

is the lens held firmly in place by the inside barrel part of the holder? is the module to far in the heatsink? g2s produce thinner beams with worse divergence, the two properties are more or less inversly proportional, the good thing is, thinner means brighter beam near apeture

pics might help

 

[Nute]

Lens is snug in the barrel, and the module is flush with the front of the heatsink. unfortunately, I am unable to take pictures at this time.

 

[10fenny]

You got your diode all the way in the module? You got the lens going the right way? You did say your three element works ok right? I guess we will need pictures with the way you are installing it as well.

 

[Pi R Squared]

It sounds like you may have one of their new ones that are 8mm long instead of 10mm, I know they were going to make this change, there was a thread about it here somewhere. I checked the AixiZ site though and it still says they are 10mm. If you compare it to your 3 element lens is it shorter?

Alan

 

[RYDorDIE278]

I Had a similar problem when i had my m140 Jayrob c6 kit with a 3 element lens and focus adapter which was 100%, but when i changed to a G2 the jayrob focus adapter was hiting the heatsink before being focused to infinity, so i had to run a standard lens ring and burn my fingers from time to time to use a G2 ,
In your case it does sound a touch worse and "Pi R Squared" may be right in saying the lens could be 2mm shorter barrel than the standard size we now use for our various single elements.

 

[Nute]

Yes, it is shorter than my three element. It is screwed in correctly with the slots to the top and the lens closest to the diode window. The diode was pressed into the module until recessed. the laser is perfect with the 3 element glass. My question is, why won't it focus to infinity? When I focus it to its smallest spot at a distance, the beam is still slightly spread open rather than uniform like the three element. If I focus it beyond its smallest point it then spreads larger again like most lenses do. All in all, I am unable to get a uniform beam and acceptable spot size. Do you think it could be the new lens barrel?

Thanks,
-Nute

 

[DTR]

Wait did they go to an 8mm barrel instead of a 10mm barrel? If so that probably won't work with the copper module unless you take off the focus ring to get it to focus. There is less than 1mm with a 10mm lens barrel with a focus ring on it at full focus before it bottoms out.

 

[jayrob]

Shouldn't really call it a G2 if it is a different optic...

I have already had one person ask me to machine just the lens barrel for a G lens, but if this is a different optic vs G1/G2, then it will not fit the same...

Wonder what they are? Guessing maybe G9 from projectors??

Since G1/G2 lenses are still available, they need to call theirs something different to avoid confusion...

Yes I have them still, and 650-G-1 as well...

 

[Nute]

Ok, I invited a friend to help me adjust the spot size at a distance, and we both confirmed that it absolutely will not produce a uniform beam or a spot smaller than 2.5 inches at 10 feet and 12 inches at 200 yards. I also confirmed that the beam continues to flair no matter how it is adjusted at its best setting, while attempting to set to infinity. I am going to say this is a problem with the lens itself and consider it a loss. It is no longer worth risking my diode window swapping lenses continuously in my southern arid environment with particulates flying everywhere. I have to say, I am extremely disappointed and will no longer be on the hunt for "G" style lenses. I will continue my builds, how to's, and reviews, but only with 3 element lenses hereafter.

 

[RYDorDIE278]

Have a search around Here at LPF for pictures and comparisons of Single element lens VS 3 element FOR EACH DIODE. you may find that what you are not happy with on your A140.... Is the Bar shape that some consider Normal
Although the length of the barrel definitly sounds shorter with this lens you have ,

When I said above "FOR EACH DIODE" i mean for example if you had a 650nm Single mode/405 Single Mode or maybe a PLP520-B1 Multimode build you may be happy with your beam using a Single element lens instead of 3 element

 

[Pman]

I used to run most of my units with genuine G-2 lenses (and from all I've read a G-1 is the only real substitute for it although for some reason I have never owned one) but have switched most of them out for 3 elements for anything with the "wings". Just can't stand seeing them anymore. I keep the G lenses though and sometimes actually use one in lower output builds.
I have some lenses that are 3- elements that are only 1/2 threaded so you can't use them in a lot of builds. Think they came from AixiZ and O-like. Anyone else run into these? I remember that before I purchased them the pics never showed them to be only 1/2 threaded.
You lens issue sounds strange. I realize this seems simple but did you try turning the lens around? Are you saying that you can focus to a fine point at other points such as a few inches away and it will then get bigger turning the lens either direction or you can't do that either?
I wouldn't give up on the G, just pay more for a G-1 or 2 and swap it out when you want.
Its cheaper to purchase a G if you buy a complete module from DTR and then add in a seperately 3-element to get rid of the bars/wings.

 

[Shakenawake]

the single element lenses I got from aixiz a a while back behaved exactly as g lenses I have gotten from DTR, both in terms of power and divergence/spot size though it's possible they have changed since. maybe check like pman said to make sure the flatter part of the lens is facing the diode and rounder side facing out, if you have not already. ultimately it's personal preferance, though I use single elements almost exclusively now, on single and multi modes. ( I like max power most of the time) I especially like them on 405s, as the divergence is great anyway and the thinner beam brightens the already hard to see wavelength, plus you get max power.

 

[DTR]

Did you try taking the focus ring off the barrel and see if that is what was stopping it from getting to focus fully?

 

[Nute]

Did you try taking the focus ring off the barrel and see if that is what was stopping it from getting to focus fully?

Yes Sir, Once it focuses best, it still has a pied beam, and adjusted anywhere beyond that best pied focus, it only gets worse.

 

[Nute]

I realize this seems simple but did you try turning the lens around?

Yes Sir, I did indeed try turning the entire barrel around out of curiosity, but to no avail. I have the lens's flat side closest to the diode window. I believe it to be a defective lens.