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LFL - long focal length G2 Lens?

SixTee9

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I'm getting ready to buy a module with G2 lens and I saw the option for G2 and a LFL - G2, can someone tell me the difference? I have done my search but I found info on a short focal length lens.

Thanks, Ron
 



Cyparagon

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Long focal length means a larger, but less divergent beam. Not all of the beam is likely to fit through it if the diode is multi-mode (depending on how much longer the focal length is), so you may also get a power loss.
 

Bionic-Badger

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Or more specifically: the "G2" is just the name for a coated 6.3mm lens with a short focal length that allows it to capture a lot of light. The LFL lens is a coated 6.3mm lens with a longer focal length (hence the LFL). With a longer focal length, but same diameter, it chops off the sides of beams with large divergences such as the 638nm, which affects their shape and can make the output look better, but with more loss.
 

SixTee9

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Thanks, that clears things up and thanks DTR for pm'ing me the answer also :beer:
 

DTR

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Yep it is actually a very interesting lens that I have been playing with for a few weeks. It has a few mm longer focal length than the standard G-2 so not like the very long focal length lenses that Lazeerer has. It also has a very slight rounding on the side that is facing the diode which is flat on the standard G-2. It passes about 5% less than the G-2 and gives a little better divergence. It is the lens I used with the 3W Menace that I reviewed so it is a very capable lens.

Anyway I sent one to Lazeerer and he has done testing on it. I will see if he can post some info on his findings here.:beer:
 
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steve001

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I'm getting ready to buy a module with G2 lens and I saw the option for G2 and a LFL - G2, can someone tell me the difference? I have done my search but I found info on a short focal length lens.

Thanks, Ron
G 2 lens info http://www.laser66.com/html/405-G-2.pdf
The EFL for both the G1 and G2 lenses is for practical purposes the same. If you want something that really can be considered a long focal length lens go to Edmumd Optics.
Optical Lenses - Optical Lens - Achromatic Lenses | Edmund Optics
They carry lenses with very high transmission through put and very low surface reflections. They have a very helpful technical staff. They have live chat.

It also has a very slight rounding on the side that is facing the diode which is flat on the standard G-2.
As I recall Edmund Optics calls that type of lens "Best Form". That type of lens is used for focusing a laser beam; not for collimating a laser beam
 

Bionic-Badger

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Edmunds optics is nice, but the lenses are expensive and not easily mounted by the "standard" Aixiz lens barrel.
 

steve001

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Edmunds optics is nice, but the lenses are expensive and not easily mounted by the "standard" Aixiz lens barrel.
I don't know if that's an accurate statement because the type of lens a G2 is, is a common plano-convex [pcx]. It has a diameter of 6.33mm. Edmunds sells a 6mm lenses of much greater focal lengths than the G2. If you are referring to these lens housings than an Edmunds 9mm or 12mm [pcx] lens can be fitted. Plus they come in a variety of AR coatings.
Copper 9mm diode mount for AixiZ 12x30 case, AixiZ

http://www.aixiz.com/store/index.php/cPath/46

Expensive is a subjective term. If one wants to minimize light losses then paying more might be worthwhile.
 
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lazeerer

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Hey Guys,

Made this video a few days ago but just now having a chance to post it.

Here is a Comparison of the LFL to a G2 lens as far as power goes.

I test 3 common diodes we use today. 405nm,445nm & 638nm.

IF you want to find the loss difference at higher powers just multiply the output and then Multiply the loss.

EX> Lens A is at 1000mW with a 10mW Loss compare to Lens B.

If you want to know what the loss is say at 3W then you would Divide 1000mW into 3000mW and your answer would be 3. Then Multiple 3 X the Loss (10mW) and you would get 30mW Loss at 3W. <<<< JUST AN EXAMPLE.


Here is the video:


I will update with picture shortly.
 
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Lazeerer that is really helpful and nice of you to take the time to make that video! :)

I think it would be really interesting as well to see photos or video for comparison of each of the beams of 445nm, 405nm and 638nm using the various lenses LFL, G2, and 3 Element to get a sense of the differing divergence and or beam size changes as well as how the multimode diode's beams look with the effect of "cutting off the wings" with the LFL that was mentioned.

Tried to +1 for the video but I guess I still have to spread more first... :(
 
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ApexProxy

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I have used DTR's LFL as well as Lazeerer's super LFL. DTR's LFL is a subtle difference that is nice for M140 builds where you want power but desire a slightly better divergence. Lazeerer's LFL is a drastic change however, in comparing the two I found that Lazeerer's LFL in one of DTR's barrels(backwards) yields outputs of nearly identical to that of a 3-element lens while DTR's LFL is a couple percent lower output than a G2 so its about 18% more output than Lazeerer's LFL. The divergence on Lazeerer's LFL however is significantly better than that of a 3-element so it replaces a 3-element lens but doesn't come close to replacing a G2 like DTR's does.
 







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