Hey, Not sure if this is the correct sub-forum to post this question. I'm still kinda new here, so sorry if I got it wrong I have a laser module with a fixed focal point of 16 mm and I'm trying to collimate that light into a beam. The point of focused light is at most a quarter millimeter across and I'm trying to get a thin beam of light that has minimal spread. I'm trying to stay below a beam diameter of 5 mm. My approach so far has been to assume the focal point of the laser as a "point source" and to use a convex lens with a focal length of 8 mm at a distance of 24 mm from the laser module. This worked for me in theory, but somehow it just doesn't work all that great in practice. The beam spreads significantly, so the spot on a wall that's just 5 meters away is already 20x20 cm large. That's about as small as I can get it. The conclusion I've come to is that I simply don't know enough about the subject and took a wrong approach. Does anyone know where I went wrong here?