#### Minamoto Kobayashi

##### Well-known member

- Joined
- Aug 25, 2010

- Messages
- 532

- Points
- 63

Hello.

I have some of those 200 mW green modules:

and in one of them I was forced to replace the lens.

Before to replace it, I put the laser at exactly 8.45 meters from a white wall (the max distance available in my apartment). With Laserglow 532 nm goggles on I have measured with caliper a dot of 16mm.

Then I have replaced the lens, and while trying to refocus the module again, I have seen that I can reach a smallest dot at the same distance.

So now I'm in doubt how to procede to obtain again the best divergence available: I must reach the same spot size of the last measurement, or I must found the smallest dot available at a 8.45 meters from the aperture?

With this program:

http://www.buildlog.net/cnc_laser/laser_calcs.htm

I have calculated 1.775 mRad with the original lens config, but I don't know what is the exact distance from aperture to the wall to obtain the best result available.

Any help very appreciated, thanks!

I have some of those 200 mW green modules:

and in one of them I was forced to replace the lens.

Before to replace it, I put the laser at exactly 8.45 meters from a white wall (the max distance available in my apartment). With Laserglow 532 nm goggles on I have measured with caliper a dot of 16mm.

Then I have replaced the lens, and while trying to refocus the module again, I have seen that I can reach a smallest dot at the same distance.

So now I'm in doubt how to procede to obtain again the best divergence available: I must reach the same spot size of the last measurement, or I must found the smallest dot available at a 8.45 meters from the aperture?

With this program:

http://www.buildlog.net/cnc_laser/laser_calcs.htm

I have calculated 1.775 mRad with the original lens config, but I don't know what is the exact distance from aperture to the wall to obtain the best result available.

Any help very appreciated, thanks!

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