Problem? with Rayfoss 200mw 660nm Red

So today I got my the two lasers I ordered. The green 100mw I received is fantastic very little to no divergence.

Before I go on to the rest of my post I want to make sure I understand divergence correctly. Divergence is how much the diameter of the dot grows or expands over a certain distance correct? I still haven't really figured out the math distance ratio part. (It doesn't help I'm not too hot with math...)

Anyway back to the problem, the red laser here is the one I'm referring to. I have been messing around with it and from what I can tell after a few feet the dot starts growing very quickly. After about 30-50 ft the dot is no longer a dot, it's quite large. I cannot measure the actual size, but it's large. I took off the head and... well photos are attached. (sorry for the quality)

I adjusted the lens and it either helped closer up or slightly at a distance. I checked from the website and says the divergence on the red and it's <1.2 at the beam aperture and my green that works just fine is <1.5 at the beam aperture.

So what am I missing?

Note: The problem existed before I adjusted the lens, if anything I helped it!

Edit: The diode looks like this, with one exception it doesn't have that base.

rayfoss said:

100% Waterproof degisn. The beam dot size is adjustable by turning the head.

Click to expand...

it's a focusable one, you can change the dot size

3zuli said:

it's a focusable one, you can change the dot size

Click to expand...

yes but it only makes it larger, not tighter

You need to manually screw the lens into (or out of) the head a bit more for better divergence. I have a few of these rayfoss focusable waterproof lasers (bluray), and they didn't arrive perfectly focused for collimation. The lenses needed to be slightly adjusted at first (plus teflon tape added).

Ash said:

You need to manually screw the lens into (or out of) the head a bit more for better divergence. I have a few of these rayfoss focusable waterproof lasers (bluray), and they didn't arrive perfectly focused for collimation. The lenses needed to be slightly adjusted at first (plus teflon tape added).

Click to expand...

I have been messing with it on and off for a few hours and I think I have dialed in pretty good. I just have to wait for this evening to come so I test some distance shots!

I should have updated my situation.

When you adjust the focus of your laser, it works like this:

Starting from minimum divergence--

Adjusting the lens close to the diode makes the divergence higher, so you get a larger spot at a distance with no focal point.

Adjusting the lens further from the diode still makes the divergence higher, but creates a focal point at which the beam is at it's minimum diameter.
The beam will converge first at the focal point and then diverge again.

You just need to find the point in the middle, where the beam diverges least.

There is no such thing as zero divergence. A laser's beam will always diverge.