# Your highest candlepower spotlight?



## BlueBeam22 (Jun 10, 2008)

I am changing this poll because I did not do a good job of explaining previously and the poll was unclear.

Please vote what your highest candlepower rated spotlight is. 

If your powerful spot/searchlight is not rated in candlepower, then go ahead and vote "30mcp or over".

I find it very interesting to have a vote on everyone's highest rated candlepower spotlight, and this poll does not apply only to portable or rechargeable ones.

This poll is not public, you are voting completely anonymously.

*Quick voting quide for some normally unrated spotlights:*

*Costco/Harbor Freight/Mega Illuminator = 30mcp*

*POB HID/3152 Illuminator = 22mcp*

*N30 = 15mcp (IIRC)*


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## monkeyboy (Jun 10, 2008)

I'm guessing you mean advertised CP?

You should bear in mind that the advertised CP of those halogen spotlights are completely exaggerated. CPF member Ra measured them to be much lower. I can't remember the exact values but it was something like a factor of 10 lower.


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## Flashanator (Jun 10, 2008)

Well 4 Advertised CP I choose the Highest you got Pal.

But for Real CP, if I had a Maxabeam id hoose 5-7


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## husky20 (Jun 10, 2008)

I think my pob is rated at 22mcp


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## BlueBeam22 (Jun 10, 2008)

I do mean advertised candlepower.

Patriot36 (or someone else) can correct me on this if I am wrong:

I figured out that candlepower ratings on cheap spotlights are exaggerated to approximately 30 times of the light's actual candlepower because some CPF members have measured under half a million candlepower from a 15mcp Thor, so it is rated 30 times more than it really is.

So using the Thor CP method a Maxabeam is equal to over a 200mcp Thor, LOL!


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## monkeyboy (Jun 10, 2008)

I'm not sure how they come up with these CP ratings. It's probably a theoretical maximum based on the filament area and reflector diameter. But you're right, the HIDs are probably less exaggerated than the cheap halogens.

I'm thinking a laser pointer would have an insanely high CP rating. Probably doesn't count as a spotlight though.


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## Ra (Jun 10, 2008)

Maxablaster does not have a advertised mean cp... What to do now??

Oh,, and do you mean Portable spotlights?

Ra.


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## BlueBeam22 (Jun 10, 2008)

Ra said:


> Maxablaster does not have a advertised mean cp... What to do now??
> 
> Oh,, and do you mean Portable spotlights?
> 
> Ra.


 
Hello Ra,

Maxablaster is 52mcp!

This is about ANY kind of spot/searchlight's candlepower.

I am editing my first post.


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## Flashanator (Jun 10, 2008)

Can somone tell me the Real CP of a Mega Illuminator with 55w 4.3K HID? :thinking:


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## FredM (Jun 10, 2008)

Flashanator 500mW said:


> Can somone tell me the Real CP of a Mega Illuminator with 55w 4.3K HID? :thinking:



What is the candlepower of a 6 Watt laser?


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## SilentK (Jun 10, 2008)

yay starting tomorow i can join the 22mcp club. :nana: POB!


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## BlueBeam22 (Jun 10, 2008)

SilentK said:


> yay starting tomorow i can join the 22mcp club. :nana: POB!


 
:goodjob:


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## Patriot (Jun 10, 2008)

:thinking: :huh:  

In an effort to maintain a healthy mental life, I'm officially banning myself from this thread and any further confusion. 









:banned:


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## karlthev (Jun 10, 2008)

What size candles are you using for the lumen measurements?

Karl


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## Illum (Jun 10, 2008)

karlthev said:


> What size candles are you using for the lumen measurements?
> 
> Karl


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## BlueBeam22 (Jun 10, 2008)

Patriot36 said:


> :thinking: :huh:
> 
> In an effort to maintain a healthy mental life, I'm officially banning myself from this thread and any further confusion.
> 
> ...


 
Good point!

Since you have that it looks like you can sell your PH50 and your MB now, lol.


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## karlthev (Jun 10, 2008)

"BlueBeam22 will be away from June 15th until June 29th."

-----BlueBeam

:thinking: Hmmm, they'll hafta close the forums! 



Karl


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## BlueBeam22 (Jun 10, 2008)

karlthev said:


> "BlueBeam22 will be away from June 15th until June 29th."
> 
> -----BlueBeam
> 
> ...


 
LOL. I plan on buying a spotlight on my trip, I couldn't be without a light but I don't think I could take a bulky flashlight on the plane.


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## LuxLuthor (Jun 11, 2008)

Patriot36 said:


> :thinking: :huh:
> 
> In an effort to maintain a healthy mental life, I'm officially banning myself from this thread and any further confusion.
> 
> ...



I didn't vote, but I have a 1.000005 billion cp spotlight.


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## BlueBeam22 (Jun 11, 2008)

LuxLuthor said:


> I didn't vote, but I have a 1.000005 billion cp spotlight.


 
:lolsign: Then I have a 3 billion candlepower Qbeam!

The rechargeable Qbeam I have is actually a very nice light, it does even better than my POB and Thor at illuminating a large area when it is on flood mode. I don't have any other lights (except for a lower powered Qbeam) that have a _true_ "flood mode".


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## FredM (Jun 11, 2008)

Just decide who has the highest then bring the meter to my lab and when my laser melts it, I can be declared the winner.


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## BlueBeam22 (Jun 11, 2008)

FredM said:


> Just decide who has the highest then bring the meter to my lab and when my laser melts it, I can be declared the winner.


 
Or else I can take the lens off my POB and the HID bulb will melt the meter more than your laser.

Look at the MR4000, I bet it is _truly _20mcp, wow! http://www.megaray.com/ But I think Ra's Maxablaster would probably stomp all over it, lol.


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## FredM (Jun 11, 2008)

BlueBeam22 said:


> Or else I can take the lens off my POB and the HID bulb will melt the meter more than your laser.
> 
> .



doubtful, I have a few POB's, I don't wear goggles or have barriers when using it.


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## BlueBeam22 (Jun 11, 2008)

FredM said:


> doubtful, I have a few POB's, I don't wear goggles or have barriers when using it.


 
Sounds like you win then!:laughing:

How powerful is your laser? DX has this laser http://www.dealextreme.com/details.dx/sku.11315 and it looks like it might be a great burning laser because of the minimal beam divergence of red lasers.

The Nighthunter I is my dream light, it is another short arc light that I think has a true 3-4 million candlepower. http://www.xenonics.com/


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## FredM (Jun 11, 2008)

BlueBeam22 said:


> How powerful is your laser? DX has this laser http://www.dealextreme.com/details.dx/sku.11315 ]



Mine is 6W and is the size of a table. That one is claimed to be 200mW but I really doubt it can actually produce that for that price.


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## BlueBeam22 (Jun 11, 2008)

FredM said:


> Mine is 6W and is the size of a table. That one is claimed to be 200mW but I really doubt it can actually produce that for that price.


 
6 watts, wow what a beast of a laser module! I might get that 200mw red one in the future because of the great price and it doesn't produce IR.

I do have a 5mw green laser and a 10mw green laser, the green beam looks amazing.

I have one spotlight (my 15mcp Thor) that looks kind of like a white laser beam to me when I shine it in the sky at night.


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## Flashanator (Jun 11, 2008)

Blue Beam ive heard that the Megaray & the MR4000 CP claims are not legit.

Makes sense as the reflector is tiny on the Megaray.

So no one can guess what CP a Mega Illuminator with 55w 4.3K HID would be? 

And you call your selves Flashaholics?:nana:

Ra, That_Guy, could you give a guess????? Me no have Lux Meter..... :mecry:Yet.

EDIT: Fred Id love 2 know the CP of your 6w laser. But I dont think CP works with Lasers. Its a whole diff thing? You would expect that laser to be far far more brighter then the 60" Carbon arc??


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## windstrings (Jun 11, 2008)

Mine is rated in lumens... not sure what the conversion to candlepower is.. so I don't know how to vote.

If [FONT=Arial, Helvetica, sans-serif]one candlepower equivalent equals 12.57 lumens, that means my "Barnburner thats rated at 8600 lumens at 75 watts and even higher at 80.. only equals 684 candlepower?.... I don't think so!.... 

I'm sure I'm missing something here, other than the gross exaggeration of "millions" of candlepower by the store bought lights?

It seems its pretty complicated based on the expert explanations on Xeray's site.

Until we get some "reasonable" accuracy as a way of measuring.. I'm not sure this poll tells much that is really helpful.

A picture says a thousand words, the beamshots are still the best.
[/FONT]


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## BlueBeam22 (Jun 11, 2008)

Flashanator 500mW said:


> Blue Beam ive heard that the Megaray & the MR4000 CP claims are not legit.
> 
> Makes sense as the reflector is tiny on the Megaray.
> 
> ...


 
The MR4000 must still out-throw a Maxabeam though knowing how powerful the MR175 is, but maybe it is more like a true 10mcp?

I would expect the 6 watt laser to have a brighter hotspot (it is a hotspot) than the 60'' and throw farther but put out a miniature fraction of the lumens as the 60'', but I might be very mistaken.


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## BlueBeam22 (Jun 11, 2008)

windstrings said:


> Mine is rated in lumens... not sure what the conversion to candlepower is.. so I don't know how to vote.
> 
> If [FONT=Arial, Helvetica, sans-serif]one candlepower equivalent equals 12.57 lumens, that means my "Barnburner thats rated at 8600 lumens at 75 watts and even higher at 80.. only equals 684 candlepower?.... I don't think so!.... [/FONT]
> 
> ...


 
It would be very interesting to know the true candlepower of a 75W BB. I have heard it (or was it a 50W Xeray) easily out-throws a 15mcp Thor, so I would guess it has around 1 million true candlepower.


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## windstrings (Jun 11, 2008)

I don't know.. I remember back when the candlepower thing got out of hand... kinda like wattage ratings on speakers.... then the next competitor had to put a bigger number or the unlearned public wouldn't think the new light was actually better.

There aren't any laws that forces vendors to prove their claim in any way... so its all about learning given reputations of individual companies as in buying power amps or speakers etc.

The measurement will change based on how big the surface is that collects it and the distance etc... it gets quite complicated with lens quality, shapes, deflections, corona, spill etc... the proof in the pudding is better assessed in beamshots, and only then if the engineer that shot them is very meticulous with his aim to be consistent, settings on the camera etc.

I really like the animated gifs because they help compare....

in real life, its hard to compare by turning one light on and then another as the human eye adjusts and compensates more for more bright.... a camera is almost better in some respects.

I do like the 80W BB as I do see a difference between it and the 75... I can't believe that last little wattage would do anything perceivable, but it appears it does.

I"ll never forget the last CPF get together I went to when I first got my 50W Xeray... it beat the other lights present so bad, I wasn't even proud as it embarrassed them so bad... now I have the BB!... quite impressive to say the least...... they are slowly getting some brighter stuff out there, but I haven't seen anything yet that I care to tote on a camping trip.


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## BlueBeam22 (Jun 11, 2008)

Even a slight increase in bulb wattage really does make a difference, for example the 130W in my 15mcp Thor seems to put out so much more light than the 100W in my 10mcp.

I think the 130W puts out 500 more lumens than the 100W and IIRC there would be the same difference between a 75W HID and an 80W HID, 500 more lumens.

The BB must be a great searchlight with its huge amount of spill and super long throwing range, I'm happy you were able to get one.:thumbsup:


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## Flashanator (Jun 12, 2008)

Not that its really important IMO, but Id take a stabb & say the Barn Burner would be 4-500,000CP?? As going by the Dec 2007 shootout pics, its out thrown by the mega illuminator (900,000+Cp) & the Sams POB & Amondotech illuminator. Seems the BB's beam isnt really for super throw, IMO.


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## BlueBeam22 (Jun 12, 2008)

Flashanator 500mW said:


> Not that its really important IMO, but Id take a stabb & say the Barn Burner would be 4-500,000CP?? As going by the Dec 2007 shootout pics, its out thrown by the mega illuminator (900,000+Cp) & the Sams POB & Amondotech illuminator. Seems the BB's beam isnt really for super throw, IMO.


 
Then it does sound like the BB is about 1/2 million CP.
How interesting that the POB out throws it.

I was looking at the beamshots and the 3152 Illuminator looks very impressive, I might consider getting one in the future.


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## lasercrazy (Jun 12, 2008)

Idk what BB they were using but mine easily out throws the POB and AI.


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## BVH (Jun 12, 2008)

Blue, if you go to the Shootout 4 thread, you can easily see that the POB throw comes no where near the throw of the BB. It's not even close. They are in a different class for both flood and throw.

I think what happens to our brain is that we see so many Lumens in a huge flood area in the foreground from the BB, that we tend to think that the light is not throwing very well by comparison. This happens to me with the LarryK14.


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## BlueBeam22 (Jun 12, 2008)

BVH said:


> Blue, if you go to the Shootout 4 thread, you can easily see that the POB throw comes no where near the throw of the BB. It's not even close. They are in a different class for both flood and throw.
> 
> I think what happens to our brain is that we see so many Lumens in a huge flood area in the foreground from the BB, that we tend to think that the light is not throwing very well by comparison. This happens to me with the LarryK14.


 
That makes sense, the floody beams of some lights makes them appear to not throw as far as lights with very tight beams, even though they do throw as far or farther.

I have noticed this with my lights, but this is the first time I have thought about how lights with floody beams appear not to throw as far.

So maybe the BB does output 1 million true candlepower?


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## LuxLuthor (Jun 13, 2008)

It's silly to talk about candlepower with spotlights. It would make more sense to discuss bullocks. The only winning play is not to vote.


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## BVH (Jun 13, 2008)

Thank you Professor Falcon!


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## windstrings (Jun 13, 2008)

Well I haven't played with the AI, but the BB definately throws... it turns night into day..... not only will you see a coon in a tree at 300 yards.. you may blind him and make him fall out!

A quite impressive feat for such a small reflector...... 

The BB is a light that you could hunt with at night with a distance that may require binoculars to get its full benefit!


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## Flashanator (Jun 13, 2008)

your right BVH, just looking @ the Shootout 4 now, BB can throw. :thumbsup:


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## FredM (Jun 13, 2008)

BVH said:


> Thank you Professor Falcon!



I instantly reognized "Professor Falcon" but it took me a while on changing "vote" to "play"


Man I love that movie.


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## SilentK (Jun 13, 2008)

Finally after reveiving my *late* POB less than 15 minutes ago, i plan on terrorizing my neighbors with 22mcp of terror!:devil: i am pretty impressed with it. a bit on the heavy side but it is awesome. cant wait to fire it up. cant wait even more when till it gets dark.


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## BlueBeam22 (Jun 13, 2008)

SilentK said:


> Finally after reveiving my *late* POB less than 15 minutes ago, i plan on terrorizing my neighbors with 22mcp of terror!:devil: i am pretty impressed with it. a bit on the heavy side but it is awesome. cant wait to fire it up. cant wait even more when till it gets dark.


 
I hope you enjoy your POB! Mine died yesterday and it won't turn on anymore, and when I try to charge it the green and red lights keep flashing back and forth.

Today I am getting a large black 5 million candlepower lantern style halogen spotlight that looks like a Maxabeam to replace my dead POB.


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## LuxLuthor (Jun 13, 2008)

BVH said:


> Thank you Professor Falcon!



Hey get your hands off my WOPR, and that's Professor Falken to you, Sir! If he would add Tic Tac Toe to the voting options, I would choose that.

PS) I closed the Joshua backdoor, so don't even think about it.


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## BlueBeam22 (Jun 13, 2008)

LuxLuthor said:


> If he would add Tic Tac Toe to the voting options, I would choose that.


 
:laughing:


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## BVH (Jun 13, 2008)

Pardon me, Professor FALKEN! Pretty good for a 55-year-olds memory, huh?


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## XeRay (Jun 13, 2008)

BlueBeam22 said:


> So maybe the BB does output 1 million true candlepower?


 
The 50 watt XeRay puts out between 1.2 and 1.3 million CP, we do not use CP numbers for marketing because for one thing they have been so abused by the cheap products that the numbers have become meaningless on most or all of them. It is all marketing hype. all of these 1-30 million CP lights are off by a factor of between 10-100X.


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## BlueBeam22 (Jun 13, 2008)

Thanks Dan,

The 50W Xeray really sounds like an incredible light, I believe the candlepower ratings on cheap spotlights are blown up to about 30x the light's actual output. I have heard that a giant (cheap) 30 million candlepower rated spotlight puts out just under 1 million candlepower, and a cheap 15 million candlepower spotlight puts out just under 1/2 a million candlepower, so for many reasons they are not nearly as good as the Xerays.

From the beamshots I have seen the 75W BB is more impressive to me than the Maxabeam or the Megaray.


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## BlueBeam22 (Jun 14, 2008)

I just got my "Motor Trend" 5 million candlepower spotlight from Pep Boys, I am amazed with it and I like it more than my POB that broke! It has an extremely bright floody beam and very powerful throw too. It has a 7'' reflector and uses a 100W 12 Volt H3 halogen bulb.

It is funny how it looks so much like a Maxabeam, lol.


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## BVH (Jun 14, 2008)

Gotta stick a 130 Watt bulb in there, Blue!


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## [email protected] (Jun 14, 2008)

Flashanator 500mW said:


> Can somone tell me the Real CP of a Mega Illuminator with 55w 4.3K HID? :thinking:



I couldn't find any reference to a 55w Mega Illuminator, have you modified the ballast/burner configuration? stock (35w HID) these things are supposed to be about 3200+ Lumen, thus having a bigger relfector than the POB HID I figure (using the exaggerated rating system) it would be somewhere around 25mcp :thumbsup:

Using the same 'exaggerated benchmarking' that would place my 55w homebrew HID spotlight between 25~30mcp... I went for a truly optimistic 30mcp :devil:


In realistic terms that would be an actual 2-4mcp


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## Flashanator (Jun 14, 2008)

Mines moded. just wacked a 55w kit in there with higher (ah) batt.

The standard 35w illuminator is around 900,000+CP on a good focus I read. So yer was just curious to know what a 55w 4.3K Kit would give it?

Im guessing 1.5-2.2mcp Tops maybe? twice the CP = only 50% more throw from what ive read on here. So it still throws puny imo. I guess i was just expecting more. 


EDIT: Cant see how the Xeray50 can have that much CP, since it looks out thrown by the mega illuminator in shooutout 4.  

:thumbsup:


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## That_Guy (Jun 14, 2008)

I've measured my Barnburner at 800 - 900 000 candlepower. It varies a lot with how well it is focused, and even from lamp to lamp. My original Barnburner lamp only measured 750 000 cp.



Flashanator 500mW said:


> Blue Beam ive heard that the Megaray & the MR4000 CP claims are not legit.
> 
> Makes sense as the reflector is tiny on the Megaray.



The old Megaray site had a table showing the illumination levels at various distances of the 125W and 175W units. According to the table the 125W Megaray is 2.2 mcp and the 175W Megaray is 3.8 mcp. This is a lot better than any HID or halogen spotlight, but only half of what the Maxabeam is capable of on boost mode. The old site is actually more informative than the new one; I don't know why they changed it.



LuxLuthor said:


> It's silly to talk about candlepower with spotlights. It would make more sense to discuss bullocks. The only winning play is not to vote.



What's wrong with candlepower? It is one of the most useful measurements we have for describing flashlights, second perhaps only to lumens. The abuse by most manufacturers is unfortunate but doesn't make candlepower useless or candlepower measurements any less valid. It just means that one has to be careful when using candlepower to compare different lights. It is the best method we have for measuring and comparing throw. It is certainly a hell of a lot better than the stupid lux @ 1m standard which most of CPF uses.



XeRay said:


> The 50 watt XeRay puts out between 1.2 and 1.3 million CP


How did you arrive at those numbers? They seem a little high too me. 600 – 700 000 cp is about the absolute max according to my calculations.



Flashanator 500mW said:


> So yer was just curious to know what a 55w 4.3K Kit would give it?
> 
> Im guessing 1.5-2.2mcp Tops maybe?



Yep, that's spot on. Theoretically it should be closer to 3, but it’s lower due to the poor quality reflector.


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## Flashanator (Jun 14, 2008)

thanks That_Guy


:thumbsup:


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## BlueBeam22 (Jun 14, 2008)

[email protected] said:


> I couldn't find any reference to a 55w Mega Illuminator, have you modified the ballast/burner configuration? stock (35w HID) these things are supposed to be about 3200+ Lumen, thus having a bigger relfector than the POB HID I figure (using the exaggerated rating system) it would be somewhere around 25mcp :thumbsup:
> 
> Using the same 'exaggerated benchmarking' that would place my 55w homebrew HID spotlight between 25~30mcp... I went for a truly optimistic 30mcp :devil:
> 
> ...


 
[email protected],

I remember the Harbor Freight HID was rated at 30mcp, and it used a 35W HID bulb and has nearly the same size reflector as your Motorpro. So with the 55W HID bulb your Motorpro is probably 40mcp (using the exaggerated rating system).

Also, The Mega Illuminator is an upgraded version of the 30mcp Harbor Freight/Costco HID, (it is the same light, just with a few improvements) so with a 55W HID bulb it should also be about 40mcp on the exaggerated rating system.


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## Flashanator (Jun 14, 2008)

BlueBeam when Mr Lux Luthor was saying CP talk is silly, I think he meant this "30-40MCP" (what id call Jibber talk) your talking about. It really is unnecessary:nana::tinfoil::nana:


:thumbsup:


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## BlueBeam22 (Jun 14, 2008)

Flashanator 500mW said:


> BlueBeam when Mr Lux Luthor was saying CP talk is silly, I think he meant this "30-40MCP" (what id call Jibber talk) your talking about. It really is unnecessary:nana::tinfoil::nana:
> 
> 
> :thumbsup:


 
Right.:thumbsup: But it would be interesting to know how much more true CP the 55W HID gives than the 35W HID in the Motorpro or the Mega Illuminator.


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## BlueBeam22 (Jun 14, 2008)

BVH said:


> Gotta stick a 130 Watt bulb in there, Blue!


 
Good idea, I will try to get one for it when its original bulb burns out, but what I would really like would be to get a blue tinted H3 for it. Do you know where I could get one of those?

I really like my new Motor Trend 5mcp spotlight, after using it outside last night I find it to be more impressive than my POB was. It uses 2x 6 volt SLA batteries to power the 12V H3. It is MUCH lighter weight than the POB was, it feels featherweight. It has a 7'' reflector so it really packs a punch.

Just like the Thors, it has a red light that blinks when it is fully charged.


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## [email protected] (Jun 16, 2008)

BlueBeam22 said:


> [email protected],
> 
> I remember the Harbor Freight HID was rated at 30mcp, and it used a 35W HID bulb and has nearly the same size reflector as your Motorpro. So with the 55W HID bulb your Motorpro is probably 40mcp (using the exaggerated rating system).
> 
> Also, The Mega Illuminator is an upgraded version of the 30mcp Harbor Freight/Costco HID, (it is the same light, just with a few improvements) so with a 55W HID bulb it should also be about 40mcp on the exaggerated rating system.


Yeah so using the reversal of exaggeration formula...

QR/Va * BS - truth = a true 2~3mcp rating :thumbsup:


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## LuxLuthor (Jun 17, 2008)

That_Guy said:


> What's wrong with candlepower? It is one of the most useful measurements we have for describing flashlights, second perhaps only to lumens. The abuse by most manufacturers is unfortunate but doesn't make candlepower useless or candlepower measurements any less valid. It just means that one has to be careful when using candlepower to compare different lights. It is the best method we have for measuring and comparing throw. It is certainly a hell of a lot better than the stupid lux @ 1m standard which most of CPF uses.



Given some of your previously useful & scholarly posts, I'm a bit surprised by your post above.

To answer your question, technically nothing is wrong with candlepower or lux or lumens or candela or foot-candle or foot-lambert, or bulb lumens, or torch lumens, Steradian, or Nit. The problem is that these terms are all poorly understood, changed over time, not used correctly, measurement standards not followed uniformly, or measurements not done properly for them to be all that useful. 

How many threads and resources do you wish me to post to make my point? How about we start with some CPF oldies:
https://www.candlepowerforums.com/threads/73275
https://www.candlepowerforums.com/threads/88
https://www.candlepowerforums.com/threads/145
https://www.candlepowerforums.com/threads/140486
https://www.candlepowerforums.com/threads/79608​Or we could glance at some less formal: 
http://www.theledlight.com/lumens.html
http://www.flashlightreviews.com/features/lux.htm​Or get into the FAQs at International Light Technologies

Or better yet, let's all go to the 64 page PDF of _*The Light Measurement Handbook*_ by Alex Ryder.

Whew, that got tedious....I know let's assume perhaps a simple strategy and look at the original definition of Candlepower and see if that is straightforward (from Wiki):
The term candlepower was originally defined in England by the Metropolitan Gas Act of 1860 as the light produced by a pure spermaceti candle weighing one sixth of a pound and burning at a rate of 120 grains per hour. Spermaceti is found in the head of sperm whales, and once was used to make high quality candles.​ Hmmmm....that really cleared things up...except I don't have any sperm whale heads handy. I know....let's go to the pure, modern redefined *International System of Units* (abbreviated *SI* from the French "_Le *S*ystème *I*nternational d'Unités") hitting up Wiki once more (Oh & ignore the pesky rounding up from 0.981 to 1.0 candela)

_Since 1948, the term candlepower was replaced by the international unit (SI) known as the candela. One *old candlepower* unit is about 0.981 candela. Less scientifically, modern _candlepower_ now equates directly (1:1) to the number of candelas — an implicit increase from its old value.​But a bit more concise and accurate is Candlepower defined as:
*[SIZE=-1]Luminous intensity in a specified direction, expressed in candelas.[/SIZE]*​OK, now we're talking!!! Oh but wait, what exactly do they mean by candela? Damn....let's hope for the best and see what that is:
The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.​Curses....foiled again! 

OK, slight sarcasm aside, and assuming some modern definition can be accepted and agreed upon, it is still nearly impossible to take into account (with any standardized accuracy) the variations in various light (luminous flux) source, reflector, focus, lens, distance from light source, position & placement of beam when measurement taken, quality/accuracy/calibration of light tester (including sensor design, size, material, spectral design, conversion circuitry, etc).

As far as I am concerned, the only truly useful way to evaluate complete lights are side by side personal viewing, and to a lesser degree a series of quality beamshot photographs done by the same team, with the same camera, witnessed and verified by a number of respected flashaholics. 

I actually do not even consider an Integrating Sphere to be all that useful when evaluating a complete flashlight, HID, spotlight, etc., since what people most care about (the hotspot, artifacts, corona, spill, color, throw) are not addressed in an Integrating Sphere.

Since you mentioned with a twinge of negative spin:


> It is certainly a hell of a lot better than the stupid lux @ 1m standard which most of CPF uses.



I will say that I stand by my "stupid" destructive point source incan bulb testing by a relatively inexpensive Meterman LM631 Lux measured at 1 Meter linked in my sig, but with full awareness that it is at best, a comparitive review that was not witnessed, and does not reflect the cases of a huge dropoff of Lux measured as the overdriven bulb aged.


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## That_Guy (Jun 17, 2008)

Lux,
I agree that many terms are “poorly understood, changed over time, not used correctly, measurement standards not followed uniformly, or measurements not done properly.” I also admit that the scientific definitions of candlepower and candela are very confusing and difficult to understand. Even I don't properly understand the scientific definition of candlepower. “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.” How the hell is anyone supposed to know what this actually means? It may be useful to a scientist, but to someone who just wants to understand the 10 million candlepower figure stamped on the side of the box of a light he just bought it is utterly meaningless.

Despite this however I do still believe that the candlepower is a very useful unit. I started writing about why I believe this, but I ended up just saying the same things I did in this thread which you’ve already read. I can’t really add much more without repeating myself. In that thread I also explain my comment about lux @ 1m being stupid. I wasn’t criticizing your destructive incan bulb tests, they are about the one situation where using lux @ 1m is acceptable because you are measuring the bulb naked without a reflector.



> it is still nearly impossible to take into account (with any standardized accuracy) the variations in various light (luminous flux) source, reflector, focus, lens, distance from light source, position & placement of beam when measurement taken, quality/accuracy/calibration of light tester (including sensor design, size, material, spectral design, conversion circuitry, etc).



Most of this doesn’t matter, at least if candlepower is measured properly. The “variations in various light (luminous flux) source, reflector, focus, lens” don’t matter because the candlepower measurement takes all these into account, which is pretty much the whole point of measuring candlepower in the first place! The “distance from light source” doesn’t matter because it is included in the candlepower calculation. The “position & placement of beam when measurement taken” doesn’t matter because candlepower only refers to the hottest part of the beam (hence peak beam candlepower). “quality/accuracy/calibration of light tester (including sensor design, size, material, spectral design, conversion circuitry, etc)” certainly is an issue, but it doesn’t really matter that much. Even an inaccurate light meter is still a lot better than the human eye for quantifying the differences between lights.



> As far as I am concerned, the only truly useful way to evaluate complete lights are side by side personal viewing, and to a lesser degree a series of quality beamshot photographs done by the same team, with the same camera, witnessed and verified by a number of respected flashaholics.



That is certainly true if you want to know “the big picture”. However if you are only interested in a specific thing about a light, such as its throw or total light output, then scientific measurements such as candlepower or lumens are best.


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## SilentK (Jun 17, 2008)

I dont think we should be arguing about how it is measured and all that. We need to get back on bluebeam's topic. lets just call it "what candlepower is you spotlight overated?"  I think we all know that none of our spotlights are realy 10 million candle power. {WWII spotlight owners cant say the same :devil: } but we are talking about what the box says it is, or what it would say. just my two cents.


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## LuxLuthor (Jun 17, 2008)

SilentK, just ignore us, and your point is valid.



That_Guy said:


> Lux,
> I agree that many terms are “poorly understood, changed over time, not used correctly, measurement standards not followed uniformly, or measurements not done properly.” I also admit that the scientific definitions of candlepower and candela are very confusing and difficult to understand. Even I don't properly understand the scientific definition of candlepower. “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.” *How the hell is anyone supposed to know what this actually means?* It may be useful to a scientist, but to someone who just wants to understand the 10 million candlepower figure stamped on the side of the box of a light he just bought it is utterly meaningless.



Exactly my point....and to illustrate that your method is not taking the defined terms into account properly to promote it as you are. What I am actually saying is that you are not measuring candlepower with your method of measuring Lux at farther distances. There are too many variables between how you are extrapolating and measuring (especially with reflector spotlights) and the actual definition of a candela.

Is what you are doing *"more useful" (contrasted with "accurate") *in certain applications? Perhaps, but you cannot call them candlepower or candela unless you comply with how those scientific terms are defined. You should call your measurements: "That_Guyumens" :laughing: and then if we all want to use our own version of measurements, they could be called "This_Guyumens" or "LuxLuthorumens." 

Going back to the Ryer Manual, this statement on p. 17, under "Collimation" section jumped out at me:



> Lenses and reflectors can drastically distort inverse square law approximations, so should be avoided where precision distance calculations are required.


IMHO, the biggest source of mischief is the lack of validity when comparing your light meter readings _(represented as actual candlepower--which they are not--using the inverse square law)_ with a particular light, light meter, technique, and room--vs. everyone else using their own version of measurement, beam/reflector angle, focus, light hardware variations, power source fluctuations, ambient conditions, reflected light (i.e. from your body standing next to hotspot; surface & color of walls & ceiling; any table or furniture that may be obstructing). Surely you can see that there can be no "standard candela" among all of us flashaholics allowing agreement upon that precise scientific term.



That_Guy said:


> Most of this doesn’t matter, at least *if candlepower is measured properly.*



There's the rub....and ergo, if it is not measured properly, consistently, and with all the controls among all those using candlepower...it is not significantly more useful than some of the other measurement terms/methods.



That_Guy said:


> The “variations in various light (luminous flux) source, reflector, focus, lens” don’t matter because the candlepower measurement takes all these into account, which is pretty much the whole point of measuring candlepower in the first place! The “distance from light source” doesn’t matter because it is included in the candlepower calculation. The “position & placement of beam when measurement taken” doesn’t matter because candlepower only refers to the hottest part of the beam (hence peak beam candlepower).



I'm sorry but I just cannot agree that all of these assumptions in your list don't matter. Read p 22 chapter 8.2 to 8.22 here, and again 8.3 to 8.8 of The International Lighttech IL-1400 meter manual, and see comments below.



That_Guy said:


> “quality/accuracy/calibration of light tester (including sensor design, size, material, spectral design, conversion circuitry, etc)” certainly is an issue, but it doesn’t really matter that much. Even an inaccurate light meter is still a lot better than the human eye for quantifying the differences between lights.


Well my Meterman says it uses the "CIE Photopic" spectrum (vs. Scotopic, etc.) described on Ryer p.11. I'm not exactly sure how that relates to your meter, and how the known detection inaccuracies using it with LED's applies to HID bulbs which can have UV, etc. The various unique light sources have specific, properly designed equipment referenced in the IL-1400 manual....so I have reason to believe it does matter.



That_Guy said:


> That is certainly true if you want to know “the big picture”. However if you are only interested in a specific thing about a light, such as its throw or total light output, then scientific measurements such as candlepower or lumens are best.



Referring to the Ryer Handbook....note how they used the "5 times" rule on page 25 to address what Curious_Character appeared to be trying to resolve at the start of his post you linked, in terms of finding the true "point source" which is mandatory for using the inverse square law. Thereafter, reading chapters 6 & 7 explains what the Steradian is (Fig 7.1), and why it is important. Figure 7.4 does a nice job (with section text) of explaining and comparing other confusing terms.

Then reading on page 36, they start a discussion of some new terms that applies to spotlights, and go into some practical examples.



> The biggest source of confusion regarding intensity measurements involves the difference between Mean Spherical Candela and Beam Candela, both of which use the candela unit (lumens per steradian).


I actually took some of the ideas from chapter 8 when doing my destructive incan testing, and found it worth reading.

I finish with a repeat quote from p. 17 of Ryer: 



> Lenses and reflectors can drastically distort inverse square law approximations, so should be avoided where precision distance calculations are required.


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