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



Would you recommend this lens?

Voldy356

Member
Joined
Aug 21, 2019
Messages
47
Points
8
Is this a good lens to buy for the mitsubishi 638nm 500mw laser diode?
 



Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,138
Points
113
If you don't mind spending a few dollars more I recommend a G8 lens with a EFL of 8 mm instead which you can buy from DTR LPF: https://sites.google.com/site/dtrslasershop/home/glass-lenses

This diode?


If the lens you posted about has a focal length of 10.5 mm (specified as that) when used with the above diode, and the diode you get has a 35 degree fast axis output, some of the beam will not make it through the diameter of the lens. If the diode you receive happens to have the maximum 45 degree wide fast axis output (specs indicate it can), over 30 percent of the beam diameter won't make it through the lens and will be blocked from getting out.
 
Last edited:

Lifetime17

Well-known member
LPF Site Supporter
Joined
Dec 15, 2014
Messages
5,828
Points
113
Hi Yes DTR is the place to go for collimating lenses as Alaskan said. The G8 is a great choice, The Mitsu 500 diode isa work horse of the 638nm diodes. That diode can be pushed to 1W+ With good heat sinking , its my favorite 638 diode .
Rich:)A5E84A1E-36EB-428E-9B18-25830CA62C32_1_105_c.jpegF8C8E442-939D-49AB-B81D-E7B4A5311F5D_1_105_c.jpeg194BE83A-3527-4C2E-9A92-0358FDAE731C_1_105_c.jpeg
 
Last edited:

Voldy356

Member
Joined
Aug 21, 2019
Messages
47
Points
8
If you don't mind spending a few dollars more I recommend a G8 lens with a EFL of 8 mm instead which you can buy from DTR LPF: https://sites.google.com/site/dtrslasershop/home/glass-lenses

This diode?


If the lens you posted about has a focal length of 10.5 mm (specified as that) when used with the above diode, and the diode you get has a 35 degree fast axis output, some of the beam will not make it through the diameter of the lens. If the diode you receive happens to have the maximum 45 degree wide fast axis output (specs indicate it can), over 30 percent of the beam diameter won't make it through the lens and will be blocked from getting out.
I am using the Mitsubishi ML501P73-02 diode, and I want the best beam specs.
 

Lifetime17

Well-known member
LPF Site Supporter
Joined
Dec 15, 2014
Messages
5,828
Points
113
HI,
To make a long story short just oder the G8 lens from DTR, and if you dont mind power loss go with a 3 Element lens .
DTR has the best and correct lenses .. Do it ...
Rich:)
 

Lifetime17

Well-known member
LPF Site Supporter
Joined
Dec 15, 2014
Messages
5,828
Points
113
Hi,
This tread makes me want to build another Mitsu 500 using a G8 lens .
Rich:)
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,138
Points
113
I have a 900+ mw pointer which uses that laser diode, but for my likes it really needs a 10x beam expander to reduce the divergence. High power red laser diodes are always high divergence devices when using a ~6 mm or smaller collimation lens, at long distances the spot becomes a wide rectangle, terrible! Put a 10 x beam expander on them and they are then fine, although a fat beam when doing that, I don't mind the fat beam at all.

Although the G8 lens is still ~6 mm diameter, the longer focal length reduces the divergence further than if using a G2, or even a 3 element lens like he asked about.
 

Voldy356

Member
Joined
Aug 21, 2019
Messages
47
Points
8
HI,
To make a long story short just oder the G8 lens from DTR, and if you dont mind power loss go with a 3 Element lens .
DTR has the best and correct lenses .. Do it ...
Rich:)
I don't mind a power loss at all, thanks.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,138
Points
113
With the 3 element lens you found, the divergence will be lower due to the longer focal length, but so will the output power. To each their own :) Only thing is, that lens is twice the price some sellers are offering the same thing for.

Techhood also owns newgazer on ebay and the price for something similar is $4.50, more than half less, but why buy a half-threaded? I prefer a fully threaded lens module.

Half thread:

Full thread:
 
Last edited:

BowtieGuy

Well-known member
LPF Site Supporter
Joined
Oct 14, 2012
Messages
6,064
Points
113
Good advice from Chris and Rich, and I agree with Chris, why buy a half threaded lens and reduce your adjustment range when a fully threaded version is available.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,138
Points
113
Look at how many threads this one has, and the FL is just as good long the one you found:


I think his product for the half-thread is probably moving too slow, thus the post, but why not just lower its price, it is priced twice as high as it should be, unless there is something about it to warrant double? Half-shells cost more?
 
Last edited:




Top