G-9 lenses and in barrel.

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10-09-2015, 00:45
masterpj

G-9 lenses and in barrel.

I've always stuck with the 3-element lenses (preferably coated ones) because they are cheap and easy to obtain through ebay.
So far I have only found G2 lenses (uncoated ones mounted in barrel from one seller minus aixis or dtr).

I read that the G9 lenses are only sliiightly better or if as good as a G2/G1 lens but the G9 lens can be cheaper because they are attached to some factory mount to diodes in a certain bar or something.
DTR sells them.. 5 for just 25 dollars but they need to be put in a barrel which I assume isn't that easy because you'd have to cut the lens to even be able to put it in a barrel.

Is it really worth using a G9/G2 lens and are the gains of using one really that significant? I saw measurements on LPF where sometimes having the G9 or G2 lens can yield an almost 1watt power increase over the 3-element. Would it also negatively affect the corrected beam shape or are there any other trade offs?
10-09-2015, 01:20
Grix

G2/G9 is about 15-35% more admissive than the 3-element depending on the diode. But yes, it does affect the beam negatively. The 3-element lens blocks the periphery of the beam, which greatly reduces the amount of noise and "splash" around the dot and thus improves the beam quality. The one-element lenses let through all the light, including the unwanted splash.
10-09-2015, 04:48
masterpj

Quote:

Originally Posted by Grix

G2/G9 is about 15-35% more admissive than the 3-element depending on the diode. But yes, it does affect the beam negatively. The 3-element lens blocks the periphery of the beam, which greatly reduces the amount of noise and "splash" around the dot and thus improves the beam quality. The one-element lenses let through all the light, including the unwanted splash.

Thanks for telling me this! This really helps because on the LPF threads minus the output they always seem to leave this out. Won't be switching from 3-element then :)