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Laser pointers (1 Viewer)

Andy Adcock

Worst person on Birdforum
Cyprus
Having almost zero experience with laser pointers, I'd like to ask the following in advance of buying one for my next trip.

1. On the single occasion I've been with a guide who used one, I actually found it pretty tricky to spot the green beam in the trees though it was in daylight. Whether this is down to my own crappy eyesight, quality of the pointer or power output I'm not sure but what is most effective colour beam in terms of visibility in daylight?

2. Cheap ones are advertised with a power output of 1mW...what is mW?

3. More expensive ones are about 4mW, does this make a great deal of difference to the visibility of the light or is it range?

4. At the cheaper end of the price spectrum, is there a particular brand I should look for or are they all 'samey' for the price.

I won't be paying the £76 that NHBS are asking that's for sure!



Cheers, Andy
 
Having almost zero experience with laser pointers, I'd like to ask the following in advance of buying one for my next trip.

1. On the single occasion I've been with a guide who used one, I actually found it pretty tricky to spot the green beam in the trees though it was in daylight. Whether this is down to my own crappy eyesight, quality of the pointer or power output I'm not sure but what is most effective colour beam in terms of visibility in daylight?

2. Cheap ones are advertised with a power output of 1mW...what is mW?

3. More expensive ones are about 4mW, does this make a great deal of difference to the visibility of the light or is it range?

4. At the cheaper end of the price spectrum, is there a particular brand I should look for or are they all 'samey' for the price.

I won't be paying the £76 that NHBS are asking that's for sure!



Cheers, Andy

#1. Green is the best color. Although as you noticed even a green Laser light is not very effective in direct or harsh light unless the power output is near 50mW.
#2. mW is milliwatt. So the higher the number the higher the power output (and the faster you will go through batteries) and your better chances of seeing in direct daylight. For this a power of at least 50mW would be recommended although some governments outlaw Laser of this power.
#3. I recommened that you get the highest mW you can, at least 5mW.
#4. Cheaper laser tends to be made in China. I would recommend a laser made in Japan. Main reason would be safety as a Lazer emits a type of radiation that is harmful to your eyes (and the birds) the Japanese laser have a filtered lens to remove most of this while the Chinese built laser tend to lack filtered glass. Try Amazon etc.
 
Many thanks dcw,

I can find nothing above 1mw on Ebay UK, very little on Amazon US and it's all from China.

Andy
 
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Many European governments have started to outlaw lasers for private use due to the potential harm. If you are birding just on your own, a laser would have no benefit that I am aware of. If you are leading a group, try to get a permit to have a high output one for commercial use.

Niels
 
Thanks Niels,
it seems that actually finding one might be a prob, I don't want to pay a lot either, hadn't realised the price of the good ones.

Will be on a trip with 5 people so would be useful.


Andy
 
Laser 303

Andy:

Having been with two guides in Panama who used lasers, I have purchased two similar pointers from AliExpress (China). They are about $usd 15 each, including two Li-on batteries and chargers. They work fine in all but the brightest sunlight, and are particularly useful at dawn and dusk.
Ignore the mW ratings given in adds. They are all wildly exaggerated.

Go to Aliexpress and search for "Laser 303". They take a while to ship from China.

Note that I had difficulty buying local (Canada) as shipping Li-on batteries appears to be a problem.

Tony
 
Green is the best, you can google why.
I use a not inexpensive powerful one selectively during daylight for eg shorebirds at distance, and long distances in general (only in daylight though) .... However my powerful laser has scared birds away in low light (woodland etc...), so in low light conditions I use a low power laser. You can get $5 or $10 dollar low power ones from china that do the job (I would get a few - that way when they break it's no big loss). The cheap ones should last a year or more if you are careful with them.
 
I wonder if anyone has an updated recommendation? My current set of green lasers have all died and I am searching for a powerful green daylight pointer of better build quality. I note that http://www.laserpointerpro.com has very bad independent reviews claiming scamming and poor quality products. Any suggestions gratefully received.
 
All I can say Chris is that after losing my first one in Venezuela and ordering a second from the same place, I've had no issues with quality or service at the above site.



A
 
Thanks Andy. The site clearly has a lot of nonsense in terms of power and original price. May have to risk it though since I can see few alternatives in the UK, where everything I have found so far is significantly underpowered.
 
Thanks Andy. The site clearly has a lot of nonsense in terms of power and original price. May have to risk it though since I can see few alternatives in the UK, where everything I have found so far is significantly underpowered.

More than happy with епру model I bought Chris, the focal point is visible in all but the strongest sunlight.


A
 
I have heard the rule of thumb that a bird can be affected by a laser beam pointing closer than one meter. On a recent Uganda birding trip, the guide would often circle the bird with his laser pointer and, sometimes, the bird flew off as if reacting to the laser. How close could a laser beam be to a bird before it detects the beam and is potentially alarmed.

I carried out a simple experiment to measure how close a laser beam can be before a bird detects it. I showed my laser pointer to my ophthalmologist. My laser pointer is labelled Laser 301 with green laser colour, 532 nm wavelength, 1 mW power, and 18650 rechargeable battery. He advised me to shine the laser at a wall and – with my back to the laser and never looking into the laser – measure the diameter of both the central beam and the dispersed light from the laser. He suggested that a human eye (and probably a bird’s eye) would detect the dispersed light. Shining a laser beam at a bird so that it noticed the dispersed beam might alert a bird. And circling a bird with a laser beam might be seen as flickering light and alarm it.

Here is the experiment and the results. I shined the laser pointer at a white wall, 4.3 meters distance. I measured the diameter of the central laser beam and the diameter of the area of dispersed light. In the case of my Laser 301 pointer, it is easy to distinguish the central area. The dispersed area has a somewhat fuzzy border, so my measurement of the diameter extends to the dispersed light area that is uniformly bright.

Two measurements are made: the distance from the laser (labelled T) to the wall (labelled V), and the distance from the center of the laser beam to the edge of the central area or the edge of the dispersed light (labelled U).

In this case, there are two measurements for UV, one of the central beam and the other for the dispersed area. The ratio UV/TV equals tangent θ, where θ is the angle between the hypotenuse and the adjacent line. This experiment finds that TV is 4.3 meters, UV for the central beam is 0.012 meters, and UV for the area of dispersed light is 1.17 meters.

Based on my measurements of the central beam and dispersed area of light, I calculate the following table. Measurements are also shown in feet, calculated as 1 meter=3.28084 feet.

UV Distance, in ms Diameter of Central Beam, in cms Diameter of Dispersed Area, in cms
5 (16 feet) 1.4 (1/2 inches) 13.6 (5 inches)
10 (33 feet) 2.8 (1 inch) 27.2 (11 inches)
20 (66 feet) 5.6 (2 inches) 54.4 (1.8 feet)
30 (98 feet) 8.4(3 inches) 81.6 (2.7 feet)
40 (131 feet) 11.2 (4 inches) 108.8 (3.6 feet)
50 (164 feet) 14.0 (6 inches) 136.0 (4.5 feet)

This experiment suggests, for example, that shining a Laser 301 beam at a bird 30 meters distance might alert a bird if the laser beam is within 81.6 centimeters or 2.7 feet. Unlike the rule of thumb that a bird may be distracted by a laser beam within one meter, this experiment takes into account the distance from the laser pointer to a bird as well as the potential effects of the area of dispersion of the laser. For longer distances, the laser beam may alert a bird that is within 1.4 meters (or almost 5 feet).
 
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When I use a laser, I will go to within a metre usually then give verbals clues from there, birds can clearly see lasers and will be spooked if they're used wrongly.
 
Hi,

He suggested that a human eye (and probably a bird’s eye) would detect the dispersed light. Shining a laser beam at a bird so that it noticed the dispersed beam might alert a bird. And circling a bird with a laser beam might be seen as flickering light and alarm it.

I've never used a laser pointer for pointing out birds, but I would think that the bird would be able to see the reflected light too.

Not sure what the idea is, but I'd think that if you're pointing out the bird, you'd probably shine the laser pointer onto some object that is close to the bird. If that happens to be between you and the bird, it will reflect light back to you, but no light to the bird. If the object happens to be behind the bird, it will see the laserpointer the same way you do, only from up close.

To optically point out the location of birds without scaring them off, I would recommend using a reflex sight, but that requires a tripod and everyone getting behind the tripod in turn.

Regards,

Henning
 
Not sure what the idea is, but I'd think that if you're pointing out the bird, you'd probably shine the laser pointer onto some object that is close to the bird.

Typcially you point to under (or above) the bird and say "see the dot, one m above!". Drawing a wide circle around the bird is another way, but may easier spook the bird. A laser in dense forest, especially tropical forest, is a much quicker to get people on the bird than "in that tree with the green leaves".
 
Hi Dalat,

A laser in dense forest, especially tropical forest, is a much quicker to get people on the bird than "in that tree with the green leaves".

Thanks for the confirmation! If we're talking about leaves, shining a laser at transparent objects might also make them visible to the bird even if they are between you and the bird.

(Since lasers can cause eye damage, I'm not sure I like the idea of shining them at birds. No such problem with reflex sights, obviously.)

Regards,

Henning
 
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