Green laser on a foggy morning

Ron Czapala

I bought a green laser pointer recently (class IIIa laser <5mW) and although it is not super powerful it looked quite impressive in the fog this morning.

My camera has a handheld night scene mode where a single image is created by combining consecutive shots reducing camera shake and image noise.

I had the laser pointer in my left hand and the camera in my right.



On a different morning ...

erco

Nice pics. I get the same effect, the laser just stops abruptly after a distance instead of fading out gradually. Always surprises me.

Ron Czapala

erco wrote: »

Nice pics. I get the same effect, the laser just stops abruptly after a distance instead of fading out gradually. Always surprises me.

Without the fog this pointer has pretty good range - I can see it about 2 blocks away.
Pointing it at a speed limit sign is neat - the whole sign looks like green fire.

The coating reflects and refracts all over the place.
madehow.com/Volume-2/Road-Sign.html

The first traffic sign using reflective sheeting was installed on the outskirts of Minneapolis in 1939. The surface of the sheeting was covered with tiny glass beads that produced the desired retroreflectivity. However, dirt tended to accumulate on the grainy surface and during wet weather, the water would coat the surface and diminish the reflective effects of the beads.

These problems were solved within a couple of years. An enclosed lens system was developed, essentially by covering the beaded sheeting with a transparent film that maintained the surface's retroreflective qualities. This type of sheeting, referred to at the time as "flat-top sheeting," is now known as engineering grade sheeting. It is the most economical grade and can be used on signs in areas with light traffic and slow speeds.

The next major development came in the late 1960s when encapsulated lens sheeting was invented, basically by adding a resin base and an additional reflector coat behind the glass beads. This high intensity material is three to four times as bright as engineering grade, and it retains its reflectivity longer; it is now the most commonly used type of reflective sheeting.

Another significant innovation came in 1989 with the substitution of microscopic prismatic reflectors for the traditional glass beads. There are about 7,000 microprisms per square inch (about 10 per sq mm) of this type of sheeting, producing about three times the brightness of the encapsulated lens variety. This is the most durable and most costly type of high performance sheeting currently available.

MikeDYur

Ron Czapala wrote: »

My camera has a handheld night scene mode where a single image is created by combining consecutive shots reducing camera shake and image noise.

I had the laser pointer in my left hand and the camera in my right.

That camera does a nice job of low light imaging.

I have two green lasers on my varmint rifle,
though one is a designator, beam width is adjustable.
Green lasers are easier to see in the daylight, and unmistakable after dark.

I remember wanting one of the early gas tube lasers, offered in the back of some publications.
Like the one man sub, I never got it.