# Why are most beam shots taken at 3 foot?

#### diggdug13

##### Flashlight Enthusiast
Why are most beam shots taken at three foot instead of a realistic distance? with the lights that we all carry around any beam shot at 3 feet will show really bright hot spot and in reality an unrealistic beam because most of the lights are used at a walking distance not at three feet where the beam would mostlikely be unusable.

I'd love beamshots to be done at like 10 feet away.

Doug

#### Delvance

##### Enlightened
Well, i do mine close because last time i did beamshots, it was still sunny so i did it in an enclosed room...so the close distance was i guess, limitatons of the environment. Wouldn't a close shot also allow people to see and compare sidespill better though ? I agree beamshots should be done in practical distances though, i was going to do some last time i reviewed the MB3W but as i said, it was light then.

#### tron3

##### Banned
Even at 3 feet the hot spot gives an idea of throw, but not always. In the least both should be done. If you find some of the older threads, some people have beam shots across rooms, and yards, etc.

Suddenly, those identical hot spots are no longer identical.

#### TrueBlue

##### Flashlight Enthusiast
Dig, it was funny to read your thread. A couple of days ago I was thinking the same thing.

Why do we estimate from one meter distance? Did it become a standard for measuring light because someone did it years ago?

How about another type of test? I don’t know the merit of this idea. At night we would put a light on a table then walk away from the light with a lux meter. When the meter reading dropped to 100 lux that would be the distance a beam would throw. Measure the distance from the lux meter to the light and it would give a realistic distance a reflector or optic would throw. Using the distance of a person’s steps would give a fairly accurate measurement of distance. In my case my average step is 20-inches (0.5 meters)…yes, I measured.

To say one light is 1000 lux and the other light 1800 lux really doesn’t translate to real life use. It would make more sense to say one light throws 3.3 meters and another throws 4.5 meters or one light throws 10-feet, 10-inches and the other light throws 14-feet, 9-inches. Measuring in meters would be easier to convert numbers.

Absolute darkness would not be necessary. Subtracting the ambient light reading from the lux meters total reading would still be valid…I think.

We might test a couple of lights trying this method. It could be a new standard for testing lights. Someone had better prepare to do a lot of walking if they are going to test a laser beam throw.

Would it be a new standard for a test? Would it be valid? Would it be the TRUE (BLUE) light test method? Lol.

This is just a thought to kick out to the crowd.

#### Kryosphinx

##### Enlightened
It would be like telling someone that that light throws 746 lux. Who knows what 746 lux looks like? Telling someone it throws 42.6 feet is so much more descriptive.

#### Morelite

##### Flashlight Enthusiast
TrueBlue, that is a great idea

#### powernoodle

##### Flashlight Enthusiast
I like a beam shot taken in a hallway, because it can give you a real world sense of throw and spill.

JIL 1.3W.

As compared to a close-up shot of the same light at 6 feet, which pretty much looks like every other shot at 6 feet:

peace

C

#### CM

##### Flashlight Enthusiast
"Why are most beam shots taken at 3 foot?"

Some of us have crappy cameras that have difficulty capturing shots at realistic distances. Also for some some strange reason, I don't like posting pictures of the inside of my house. Something about voyeurism and such :thinking:

:

#### Delvance

##### Enlightened
Good idea TrueBlue, but something not easily carried out methinks. First of all, the tester would need to find a relatively flat and long piece of ground, we'd have to worry about people walking pass "nice light! *Yonk*" And the further the light throws, the more we'll have to walk, thereby making the discharged time to measure time not constant across the board. Also with the lux meter, you're going to have to hold it pretty steady and at a straight on angle to the light, which may be hard without something to mount it and light etc.

I guess there's no real easy way to convey the throw of a light...

For example (real),
i've got two ROPs. A 2D modamag holder with 6 cbp's, metal reflector, UCL and a solderwicked spring. Hot cells i can get 40,000+Lux easy.

A 3D bored host, with 4x18650s, a low loss reflector, solderwicked spring, UCL. This light can only measure about 28,000 Lux or so. (The low loss reflector along with the cam mechanism doesn't allow perfect focus, but rather, a big circle of light followed by sidespill)

In real world usage, my 3D throws further than my 2D...yet my 2D measures higher. I think what's happening is the 2D has a powerful "line" of intense light then the rest of the hotspot weakens off. This "line/beam" of light at 200 metres away, can't really be detected with human eyes easily (or with my eyes at least). Bear in mind, the light has landed on brown coloured bricks, so it's very hard to detect, or whatever else your shining on (probably won't be white coloured).

Now my 3D shining at the same target, lights the whole target (actually a unit in my case) up, due to the lightspread of the hotspot being much better and also the hotspot being much larger.

So my 3D ROP in actual use, throws further than my 2D ROP, which has a 12,000+ lux advantage =/

#### Delvance

##### Enlightened
CM said:
"Why are most beam shots taken at 3 foot?"

Some of us have crappy cameras that have difficulty capturing shots at realistic distances. Also for some some strange reason, I don't like posting pictures of the inside of my house. Something about voyeurism and such :thinking:

:

*Eagerly awaits for home beamshots from CM* :devil:

Case in point =P

#### chevrofreak

##### Flashlight Enthusiast
I do beamshots on a wall at about 3 feet to show the beam shape and spread compared to another light.

O

##### Enlightened
chevrofreak said:
I do beamshots on a wall at about 3 feet to show the beam shape and spread compared to another light.

But why 3 feet? Why not 2 feet, or 5 feet? All of them will show the beam shape and spread compared to other lights, so who decided that 3 feet was the best?

#### chevrofreak

##### Flashlight Enthusiast
Thats how far I have to be to fill the whole picture when I'm holding a light at arms length and the camera at my face

O

##### Enlightened
chevrofreak said:
Thats how far I have to be to fill the whole picture when I'm holding a light at arms length and the camera at my face

Makes enough sense to me.

#### cheapo

##### Flashlight Enthusiast
I PREFER OUTDOOR BEAMSHOTS.

-David

#### Somy Nex

##### Enlightened
For me, I take some close-range shots, usually around 1-3 ft. to show the entire beam. If you go back too much farther, the camera might not be able to capture the full beam for reference.

That said, I also have a running series of "corridor" shots, which I just have to hawk at this moment, because last night I spent over an hour taking a whole series of shots for a number of lights. You can view them at http://www.pbase.com/somynex/corridor, and there are pictures of almost all the lights in my signature line (except those greyed out in light grey which are the ones I do not have yet), with the addition of the SF E2D and Gladius. They are an attempt to take pics comparable across the board of all the lights in a more "practical/real world" setting. Here's a sample of the U2 (SF123s, High) at top, and the Gladius (high) at bottom. You can click on the pics to go to the full size version and the gallery.

It's about 30 yards to the photocopier at the end of the corridor, and they are taken at standardized camera settings of ISO64, f4.0, Daylight white balance, and at 4s, 2s, and 1s respectively.

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