# I love the 1185 in the FM3X head! *Added outdoor beamshots!*



## mudman cj (Sep 16, 2009)

I just snagged the last FM3X Megalennium head and I am really impressed with the throw using the 1185 lamp. It has taken me a while to settle on this combination as my favorite throwy light, so let me start with some background on my flashlight purchases.

I found CPF a few years ago while researching the 'new' LED lights (Luxeon I, III, and V) that had just come out and was hooked right away. I started off with a couple of LED lights and then a Mag mod, and picked up a couple more incandescent lights before tending towards LED lights for the majority of my purchases. When warmer tint LEDs came out, they had me thinking that incandescent's days were numbered. But after many purchases and much research I have come back to incandescents. You just can't get the same light out of an LED. And if you want throw, LEDs just can't match the beam from a good incan. By no stretch of the imagination am I an LED basher. LEDs have their purposes and I carry 2-3 LED lights on me at all times. But I recognize the advantages and disadvantages of each.

Most of my LED lights are general purpose, neutral tint and single cell lights. They tend to put out a peak reading of a few thousand Lux at 1 meter. I have a couple of LED lights that can exceed a peak reading of 10,000 Lux at 1 meter at turn on, and I know of one that exceeds a peak reading of 45,000 Lux at 1 meter (a custom ArcMania light using a 6 die Ostar LED and a series of 3 lenses). I don't know the light intensity of the DEFT, but I think it would exceed all of these. But, they are still not full spectrum lights and this can have detrimental effects in some circumstances. Due to the lower surface brightness of LEDs compared to an incandescent filament, few LED lights exceed peak readings of 10,000 Lux at 1 meter, especially the higher lumens output 4 die emitters like the P7 or MC-E.

Most of the incandescents lights I have put out a peak reading of around 30,000 Lux at 1 meter using somewhat standard reflectors like the standard size Mag reflector or the Surefire KT4. I measured a peak value in the 30,000 Lux at 1 meter range with both the 1111 and 1185 in the KT4. *Edit: With more fully charged batteries I measured a peak lux value of about 54,000 for the 1185 in my KT4 head.* With a 1111 in my 2" deep Mag reflector I measured a peak reading of just over 45,000 Lux at 1 meter. Not bad! But then I saw the 1185 in the 3" diameter FM3X and I knew it was something special. A lux measurement on freshly charged AW 2600mAh 18650 cells peaked at over 120,000 Lux at 1 meter.  And the beam is much more than just a hotspot. There is a large corona that is bright in its own right and the wide spill you would expect from a 3" diameter head like this. I have the VLOP reflector in my FM3X and my Megalennium has a McClicky switch that is the icing on the cake. This FM3X head makes the Megalennium a beautiful and usefull light to behold. So here's to Fivemega for making one of the most awesome flashlights ever fabricated. :bow: Thank you Varooj!

Gratuitous eye candy:
















This is a beamshot with the light 5 meters from the wall. The hotspot is around 6-8" or 15-20 centimeters across (I am estimating here).





And this is the same beamshot, but at -1 eV to show the size of the hotspot.

I would include some outdoor beamshots, but lack an appropriate location here at my house to show what it can do. I will take it out someday soon to a nice range and take some pics to share.

OK, the wait is over. Here are the outdoor beamshots I promised!

First of all, here is a control shot of the range without the use of any flashlights:





Next up is the 1111 in my KT4 powered by 2 AW Li-ion C cells:





Third is the 1185 in my KT4 powered by 3 AW 2600mAh 18650 cells:





Last but certainly not least is the 1185 in my FM3X again powered by the 3 AW 2600mAh 18650 cells:






In these shots, the distance to the yellow sign in front of the tree is about 150 meters and the distance to the tree behind the sign is about 170 meters.


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## RichS (Sep 16, 2009)

*Re: I love the 1185 in the FM3X head!*



mudman cj said:


> A lux measurement on freshly charged AW 2600mAh 18650 cells peaked at over 120,000 Lux at 1 meter.


120,000 Lux??!!  I don't even know that I can comprehend that, especially from a light that's not a 50W+ HID! Wow...I've got to see that thing in action - beamshots please!!


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## Icebreak (Sep 16, 2009)

*Re: I love the 1185 in the FM3X head!*

Beautiful. Just Beautiful.

Extrapolating from my mind's image memory and your beamshots, I can tell what it is doing. In other words, I know the 1185 well and that Megalennium is really dialing the rays in nicely. You've got all the components of a beam optimized with a stunning (what I call) superspot within the hotspot.

Awesome.

[EDIT] Rich I didn't see your post until after I posted. [/EDIT]


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## mudman cj (Sep 16, 2009)

*Re: I love the 1185 in the FM3X head!*

While it does not match the throw of an HID, it ain't too shabby either. You have to love the spectrum of incandescent, the instant jump to full output, and bulbs that are cheap and readily available. For comparison to an HID for which I could find Lux measurements, the Titanium L35 (35W HID) with a 4" reflector IIRC and weighing in at just under 3 pounds put out an estimated >230,000 Lux as measured by selfbuilt (thank you selfbuilt!). But it took over 30 seconds to warm up to that output level.


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## ElectronGuru (Sep 17, 2009)

*Re: I love the 1185 in the FM3X head!*

Beautiful setup. I sold my black FM3V-2 and still miss it!


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## LuxLuthor (Sep 18, 2009)

*Re: I love the 1185 in the FM3X head!*

Your beamshots make it clear! It is a great combo. :thumbsup:


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## BSBG (Sep 18, 2009)

*Re: I love the 1185 in the FM3X head!*

I enjoy my Megalennium / 3X combo as well - lots of spill, but a tight, long throwing hot spot as well.


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## I came to the light... (Sep 18, 2009)

*Re: I love the 1185 in the FM3X head!*

It looks like this is a great combination. I have been an all LED person until recently, when I discovered 1185, and shortly after FiveMega - those two are a winning combination every time :twothumbs

off topic: I have a Megalennium that I'm trying to get to work with AW 2600mAh 18650s, but they don't make contact . The 3 bumps push the negative contacts too far away from the nearly flat contacts on the flashlight. Did you just put solder blobs on one or the other, or is there a better way to get this beauty working?


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## Raybo (Sep 19, 2009)

*Re: I love the 1185 in the FM3X head!*

I'm a 1274 kinda guy, but your beam shots just might make me second guess myself.


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## nfetterly (Sep 19, 2009)

*Re: I love the 1185 in the FM3X head!*

I had the same issue with lack of contact - but light started working for me by itself - initially I thought the problem was elsewhere. 

I have a thread on it (link below) & there some others reported in the thread (DM51 combined another thread on it into the one I started). You can read what they did.

https://www.candlepowerforums.com/threads/229423


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## DM51 (Sep 19, 2009)

*Re: I love the 1185 in the FM3X head!*

It's a tremendous combination. The crucial thing is to get the bulb shimming right - the filament's precise position in the reflector (especially a SMO reflector) is very important to get the best focus and throw.


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## I came to the light... (Sep 19, 2009)

*Re: I love the 1185 in the FM3X head!*



nfetterly said:


> I had the same issue with lack of contact - but light started working for me by itself - initially I thought the problem was elsewhere.
> 
> I have a thread on it (link below) & there some others reported in the thread (DM51 combined another thread on it into the one I started). You can read what they did.
> 
> https://www.candlepowerforums.com/threads/229423



Thanks for the link. It looks like I need to contact FM, since I can't solder the contacts inside the flashlight.


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## QtrHorse (Sep 19, 2009)

*Re: I love the 1185 in the FM3X head!*



I came to the light... said:


> Thanks for the link. It looks like I need to contact FM, since I can't solder the contacts inside the flashlight.


 
I am in the same boat. I cant get the host to work with any cells. I don't mind soldering the top brass caps but what about the bottom? Then my host is modified and if I choose to sell it at a later date, it will not have much of a return.


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## mudman cj (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*

I chose a method that requires no modifications to the original hardware. I bought some 5mm diameter x 0.5mm thick *Edit:make that 1mm thick instead* rare earth magnets and soldered a tiny blob to the center of one side. They fit down between the three bumps on AW 2600 18650 cells. If you face the solder bump up, then it will make contact with the Megalennium contacts. I ruined a couple of magnets before I was able to solder to them quickly enough to avoid demagnetizing them, so if you decide to try this plan on buying some extras.

Here is a pic of one of the magnets nestled between the three bumps on the negative side of the AW 2600 18650:




Note how small and how short the solder bump in the middle is. This is all it takes to make contact. With one of these for each battery, the heights of each will match up and everything goes together fine.


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## I came to the light... (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*



mudman cj said:


> I chose a method that requires no modifications to the original hardware. I bought some 5mm diameter x 0.5mm thick rare earth magnets and soldered a tiny blob to the center of one side. They fit down between the three bumps on AW 2600 18650 cells. If you face the solder bump up, then it will make contact with the Megalennium contacts. I ruined a couple of magnets before I was able to solder to them quickly enough to avoid demagnetizing them, so if you try this plan of buying some extras.
> 
> Here is a pic of one of the magnets nestled between the three bumps on the negative side of the AW 2600 18650:
> http://i122.photobucket.com/albums/o272/cjmonz/P1050003.jpg
> ...


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## mudman cj (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*

I should add that since these magnets are so small, you can't wait for the solder to fully melt and form a puddle like you normally would. By that point the magnet will already be ruined. I applied some flux on the magnet to promote wetting and then applied the solder directly to the iron tip. Next, I touched the molten solder on the iron tip to the magnet just long enough for the solder to transfer over and then blew on it to cool it down. It also helps to have the magnet already stuck to a piece of metal to help transfer heat away and of course to keep it in one place.


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## socom1970 (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*

Hey CJ! 

I am sooo glad you were able to snag one of the 3X heads. The KT4 head just didn't do the Megalennium/1185 combo it's proper justice. That and I'm sure you've been wanting one ever since I showed you mine!:nana:

Our next get-together will be very interesting, to be sure!


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## mudman cj (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*

Yeah, I have _you_ to thank for making me think I needed one so badly.  When the second-to-last one sold I nearly panicked because I was in the process of trying to sell other lights and parts to scrape up the funds for this along with another Milky mod, which BTW I am waiting to receive before setting up the next get-together.


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## I came to the light... (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*



mudman cj said:


> I should add that since these magnets are so small, you can't wait for the solder to fully melt and form a puddle like you normally would. By that point the magnet will already be ruined. I applied some flux on the magnet to promote wetting and then applied the solder directly to the iron tip. Next, I touched the molten solder on the iron tip to the magnet just long enough for the solder to transfer over and then blew on it to cool it down. It also helps to have the magnet already stuck to a piece of metal to help transfer heat away and of course to keep it in one place.



Thanks for the advice. I'll admit I've almost never soldered anything before, so this might take a few tries.

edit - turns out my magnets are too big, and I'm having trouble finding the right size online - the best I've found is 4mmx1.5mm at $.96 each. Any idea where you bought yours?


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## I came to the light... (Sep 20, 2009)

*Re: I love the 1185 in the FM3X head!*

is it possible to a .5mm magnet without the solder blob? what about a thicker magnet?


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## mudman cj (Sep 21, 2009)

*Re: I love the 1185 in the FM3X head!*

Without the solder blob I only got contact sometimes. With them I get contact every time. :thumbsup: Thicker magnets would work to a point, but if they get too much thicker the second O-ring may not seal. Actually, after looking up the magnets I believe I made an error when I said they were 0.5mm thick. I am pretty sure they are 1mm thick. I did have some 0.5mm thick magnets, and they fractured very easily. The ones I used for this application are thicker.

Here are the ones I bought.


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## I came to the light... (Sep 21, 2009)

*Re: I love the 1185 in the FM3X head!*



mudman cj said:


> Without the solder blob I only got contact sometimes. With them I get contact every time. :thumbsup: Thicker magnets would work to a point, but if they get too much thicker the second O-ring may not seal. Actually, after looking up the magnets I believe I made an error when I said they were 0.5mm thick. I am pretty sure they are 1mm thick. I did have some 0.5mm thick magnets, and they fractured very easily. The ones I used for this application are thicker.
> 
> Here are the ones I bought.



Thanks for the link and advice - I just ordered 10. Hopefully it will work for me too


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## I came to the light... (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

Magnets got here today, so I put them onto all the "-" contacts, and no luck. Then I tried leaving those on and putting larger magnets on the "+" contacts, and it works! It is a solid contact, with no soldering. Thank you for your advice and the link mudman :thumbsup: The Megalennium is very nice when its working - now I need to get one of these FM3X heads! 

BTW, my megalennium w/ Surefire KT4 turbohead reads around 50,000 lux at 1m, so it looks like the head does better than double the throw.


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## mudman cj (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

That's great news. Does the tailcap still tighten past the second O-ring completely? Have you tried swapping battery positions to see if the connections are reliable?

I am also curious about the differences in our lux readings. My batteries were not fully charged when I measured 30,000 lux, so I need recharge and repeat my measurements with the KT4. What was the state of charge on your batteries when you took the measurement? How did you take the lux reading? I actually measured from 5 meters and calculated the lux reading because I have read that the result is generally more accurate when using throwers. Of course, there could also be differences in focusing here, so I don't know if we will ever get our readings to agree, but I would like to see if we can iron out some of the differences.


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## Patriot (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

When trying to reconcile lux numbers for KT4 heads, keep in mind that there are huge differences in reflectivity between individual sample. The variation is great enough that I'd be surprised to see any independent tests match.


Just a few examples


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## Illum (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

ahh...so I'm not the only one to think KT4s are different in texture between generations:candle:


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## Patriot (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

.....and sometimes within the same generation.


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## I came to the light... (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*



mudman cj said:


> That's great news. Does the tailcap still tighten past the second O-ring completely? Have you tried swapping battery positions to see if the connections are reliable?
> 
> I am also curious about the differences in our lux readings. My batteries were not fully charged when I measured 30,000 lux, so I need recharge and repeat my measurements with the KT4. What was the state of charge on your batteries when you took the measurement? How did you take the lux reading? I actually measured from 5 meters and calculated the lux reading because I have read that the result is generally more accurate when using throwers. Of course, there could also be differences in focusing here, so I don't know if we will ever get our readings to agree, but I would like to see if we can iron out some of the differences.



Yes, the tailcap tightens all the way. The other magnets are wider, but also 1mm thick, so there isn't that much extra length. 

Batteries were almost fully charged, probably around 4.17v. I took the measurement at 1m, but I think that the reading would go up, not down, if calculated from 5m. 

A little off topic, I don't understand this whole 5m calculation using the inverse square law. That law applies to light expanding from a point source in a uniform sphere - it is derived from the surface area of a sphere, and has nothing to do with the dispersion or degradation by the medium the light travels through. Focused light should not obey this law - for example, I have experimentally verified that lasers do not dim according to the inverse square law (although I have not tested flashlights yet). 

Anyway.... Patriot, mine appears to be most similar to the third type. It looks like that would reduce output but increase throw... ?


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## I came to the light... (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

OK, I just took some more measurements, and converted to 1m using the inverse square law. Batteries were down to 4.01-4.03v this time. 
1m: 41,000
2m: 11,000.....->....44,000 at 1m
3m: 5,000.......->....45,000 at 1m
4m: 3,300.......->....52,800 at 1m
5m: 1,900.......->....47,500 at 1m

I did adjust the bulb height until it gave me a nice medium size and intense hotspot, but I don't think it is focused perfectly, or enough to nearly double the throw.


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## mudman cj (Sep 26, 2009)

*Re: I love the 1185 in the FM3X head!*

I see your point about the inverse square law both in theory and from your measurements. This was a case of me just accepting what others were doing without really thinking critically about it. Bad me... :whoopin:

But, there is something potentially interesting in your data since the readings increase from 1 to 4 meters but then decrease at 5 meters. This could be due to a decrease in output as the batteries drain (assuming this point was measured last), or possibly just measurement variation.

Anyway, I decided to take a look at the data assuming the inverse square law is not quite true by fitting the data with an exponential least squares fit. By doing so I ended up with the following plot:






As you can see, the exponent of the fit is not quite 2, but is less. This suggests that perhaps flashlights do not always follow the inverse square relationship. This is by no means a complete analysis. For one thing, there is that unexplained deviation at 5 meters. Furthermore, much more data should be collected at more than 5 points and from different lights and by different people. I will be starting a new thread tomorrow to discuss this and then I will invite others to take measurements and contribute their data for analysis. 

Once we gather enough data we ought to be able to come to some conclusions about how flashlights tend to throw. The generally accepted convention of defining throw as the square root of lux at 1 meter has been bothering me for some time now, and I think it tends to underestimate throw. Of course, we would also have to agree on the threshold lux value at which a light can be said to throw to a target. I would like to develop a way of calculating throw from lux measurements that agrees better with observations in the field and perhaps also with manufacturer ratings.

Thanks to I came to the light... for initiating this discussion.


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## Illum (Sep 27, 2009)

*Re: I love the 1185 in the FM3X head!*

what? no field beamshots?

seeing this makes me want to go back to driving 1185s in my M6...


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## mudman cj (Sep 27, 2009)

*Re: I love the 1185 in the FM3X head!*

Patience...patience...


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## mudman cj (Sep 27, 2009)

*Re: I love the 1185 in the FM3X head!*

I took new measurements of the 1185 in my KT4 head using a new data reduction technique and I came up with a peak lux value of 54,000. I think the main reason for my low reading the first time was because the batteries were less charged. 

Also, using the method I describe in this new post, I would like to refine my peak lux measurement for the 1185 in the FM3X head to 117,000 lux. The batteries are not quite as charged up as they were when I took my first measurement, but I can be more sure of this result because it is an average of many readings taken at different distances and then fit to the inverse square relation.

At any rate, I think it is fair to say that the FM3X head with VLOP reflector doubles the peak lux for the 1185 bulb.


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## LuxLuthor (Sep 27, 2009)

*Re: I love the 1185 in the FM3X head!*



I came to the light... said:


> A little off topic, I don't understand this whole 5m calculation using the inverse square law. That law applies to light expanding from a point source in a uniform sphere - it is derived from the surface area of a sphere, and has nothing to do with the dispersion or degradation by the medium the light travels through. Focused light should not obey this law - for example, I have experimentally verified that lasers do not dim according to the inverse square law (although I have not tested flashlights yet).



You don't know how happy that made me to read your post. The inverse square law is invalid in reflectorized testing. Almost no conclusions can be drawn when discussing lux/lumens in such a setting. You cannot say that the FM3X with VLOP doubles the lux of the 1185. Well, I take that back. You can say it, as was obviously just done in the previous post. What I should have said is that it is not accurate.

Although it takes time to follow the links I posted in this and the next few posts, it is a background worth obtaining.


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## I came to the light... (Sep 27, 2009)

*Re: I love the 1185 in the FM3X head!*

That's an interesting analysis, thank you for posting it. Now I'm worried I should have given you better data to work off of...

I don't know if there can be a standard to measure throw via a single measurement of lux. The beam angle can vary between fully dispersed (which would obey the inverse square law) to parallel, like a laser, which does not diminish except because of particles in the air. Maybe a better method would be to take two measurements, and use them to calculate the angle of dispersion, then use that to calculate the point at which the illuminance is reduced to 10 lux (Ra's standard). 

We would also have to account for dispersion due to the air, but after 10 minutes googling I can't find a constant for that... if this develops into anything I'll put in whatever time it takes. 

The above method would not be fully accurate due to the fact that the flashlight does not emit all of its light at the same angle, but I think it would be better than a simple lux measurement. 

I'm glad you got a similar measurement - I was getting worried about my meter.


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## I came to the light... (Sep 27, 2009)

*Re: I love the 1185 in the FM3X head!*

OK, now both the babies are agreeing with me, I know I'm onto something  (seriously though, thanks for chiming in)

Thanks for the link - I'm going through it now.


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## mudman cj (Sep 28, 2009)

*Re: I love the 1185 in the FM3X head!*



LuxLuthor said:


> You don't know how happy that made me to read your post. The inverse square law is invalid in reflectorized testing. Almost no conclusions can be drawn when discussing lux/lumens in such a setting. You cannot say that the FM3X with VLOP doubles the lux of the 1185. Well, I take that back. You can say it, as was obviously just done in the previous post. What I should have said is that it is not accurate.



Lux, I substantiated my claim in the link I provided, which it seems you chose to ignore in favor of a statement that supports your preconceived notions. Although it takes time to follow the link I posted in this thread, it is a background worth obtaining. 

In that thread I show that the inverse square law holds for LED and incandescent flashlights up to the 1185 in a FM3X head. Sure, I had to throw out some of the data measured at very close distances, especially for the FM3X head, but the remainder of the data follows the inverse square law. I do not have any HIDs to test, but I suspect one would have to take measurements at still greater distances before the results would begin to follow the inverse square relation. But there is no reason to assume that light sources do not follow the inverse square relation given sufficient distance from the source to eliminate reflector effects. _The key is to get far enough away that the source appears like a point source of light._

Allow me to quote Ra from one of the links posted by LuxLuthor in his link:
"If your torches do not follow the inverse square law, then you are probably measuring the lux-output too close to the torch. (reflector not yet fully lit by the source..)"

I began this work with the idea that the inverse square law may *not* be valid for flashlights. After many hours of careful measurements and data analysis I am forced to conclude that the inverse square law is in fact valid for flashlights with reflectors with the important caveat that the measurement is far enough away from the light to eliminate reflector effects. Furthermore, I have determined and shown just how to decide where that distance lies through data analysis.

I have shown that the lights I am comparing both follow the inverse square relation past a certain distance and I have taken measurements at multiple distances and averaged the results of the fit data. I used the same bulb with the same batteries at the same state of charge and measured them with the same meter. So, in what way is it *not* accurate to say that the FM3X with VLOP doubles the peak lux of the 1185 over the KT4 head? :thinking:


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## LuxLuthor (Sep 28, 2009)

*Re: I love the 1185 in the FM3X head!*

Mudman, I read your much more carefully designed linked post. I still feel there are too many uncontrolled variables to establish a fixed and absolute answer as you did. I also don't necessarily agree with Ra's statement in this post either. My statements were not made as expressions of idle preconceived notions.

I agree that the farther you get from a particular light, the more it *begins* to comply with the strict definition of Lux or Lumen measurement. To start, there must be accurate measurement complying with: 



> 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.





> A Lumen is equal to one foot-candle falling on one square foot of area.





> One lux equals one lumen incident per square meter (instead o square foot) of illuminated surface area.


A few references which I feel should be read and completley understood so you are aware of variations from fundamental rules and required standards, and to make sure you are not deviating. I had to read and think about these, read other resources, and come back to them perhaps as many as 10 times before I fully understood all the concepts.


Ryer Manual


Internaltional Light Handbook (IL400) mostly 8.2 to 8.22 & 8.3 to 8.8


XeVision Resouce
Now my list off the top of my head of questions/concerns that I do not believe have been addressed when you (or Ra) made their measurement claims in a setting with a reflector, whether an incand or HID source. If these were fully addressed, and test platform fully identified, there may be more validity than I'm giving now.



1) Brand/quality of photometer.


2) Is photometer calibrated?


3) What light source is it calibrated to measure?


4) Which Spectral Response scale is being used?


5) Is all ambient light totally removed from measurement area, and environmental conditions (dust, humidity, etc) controlled?


6) Is Photometer sensor exactly perpendicular & at same height of point source for all measurements?


7) Are all non-light related reflecting sources (walls, floor, ceiling, objects) removed so there can be no interferance with point source in any way? See Ryer Chapter 8 for guidance.


8) Is the precise, exact same spot in beam measured at all distances?


9) Is light source output controlled by regulation?


10) If lamp power source not regulated, is power source maintained at exact same voltage & current for all measurements?


11) Given my observation that bulb output as a result of reduced bulb life in some cases, dropped dramatically and proportionately to degree of bulb overdrive...was there any overdrive from standard WA spec for 1185?


12) Were measurements repeated to verify that examiner methods were consistent and repeatable & that bulb age output deterioration has not occurred?


13) Is axis of light fixed and locked for all measurements?


14) What determines bulb position relative to reflector focal length?


15) Assuming same bulb was used with same bulb holder in comparing two reflectors as you did, what steps were taken to include optimal bulb position in focal lengths, differences in reflector coating/texture, bore hole diameter, identical volt/amp power supplied in both settings?


16) If lens was used in reflector comparisons, was it made of identical material with same thickness, refraction, cleaned, scratched?


17) Was an assumption made that if a series of lux measurements fit neatly into an inverse square plot, then those readings must be valid because they internally correlate with each other? Versus the possibility that in your attempt to make your data fit the inverse square law, you perhaps have erroneous data that internally correlates with the same degree of error. If values were discarded because they didn't conform with other values, perhaps the discarded values were less erroneous. Perhaps the true value lies somewhere in between???
I would likely come up with more questions if I thought about this in more detail, and had a better understanding of your testing methodology, and re-read all the various resources I have benchmarked from previous explorations of the topic.


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## mudman cj (Sep 28, 2009)

*Re: I love the 1185 in the FM3X head!*

Well sir, I concede that you statements were apparently not made as expressions of idle preconceived notions.

Clearly, my testing was not to the rigor that would be required to satisfy all of your questions. Nor do I have the desire or resources to attempt to meet them. I would be wasting my time to attempt a defense of my method in light of your laundry list of questions; however, I will have you know that I did not assume the lux measurements would fit neatly into an inverse square plot. On the contrary, I hoped to find a systematic deviation from the inverse square plot regardless of distance, but the data simply does not support such a conclusion except at very close distances. 

Keep in mind that I am not attempting to declare that I have determined the absolute true value of lux in my measurements for publishing in a scientific journal. I was just after a good relative comparison between different lights. Even though that addresses some of your questions, others undoubtedly remain. My main goal was to improve the often used method of measuring lux at one distance and reporting that.

Perhaps you may be moved to attempt your own set of lux measurements as I was, but with more thorough consideration given to the list of questions you posted. This may be the best way for you to answer the question of whether reflectored light sources conform to the inverse square law or not. There is nothing quite like doing the work yourself when it comes to being convinced of the results.

I still think my measurements were good enough to conclude that my FM3X doubled the peak lux of my 1185 compared to the particular KT4 I have, but I expect that you will remain unconvinced. So be it. No hard feelings Lux.

I still love the 1185 in the FM3X head!


----------



## LuxLuthor (Sep 28, 2009)

*Re: I love the 1185 in the FM3X head!*

Mudman, my comments are really not made in as negative of a manner as you (or others) may perceive them. That is the problem with posting/writing things on the internet vs. in person. I had a similar back and forth with "That_Guy" in the other thread. These discussions certainly have not risen to the level of hard feelings as far as I am concerned.

There's nothing wrong with all of us trying to improve the understanding and rigorous methodologies to get more accurate results, but it is important to recognize where we are providing relative comparisons, and implying absolute certainties. 

I think this is important because people will take what someone says with stature like Ra, or AWR (back when he had stature), or you--and repeat it enough times that it becomes a "CPF Law" rather than a relative, uncontrolled, interesting comparison.

I wholeheartedly agree that the FM & other 3" reflectors (as well as FM's 2" Deep, 2.5" Turbo) can have dramatic improvements with various bulbs. I tried to demonstrate some of that in a visual, but non-scientific manner in this shootout. 

If there was a doubling of the hotspot lumen/lux claim between those two reflectors, my suspicions and bold statement of inaccuracy were especially prompted by reading your comments noting lack of control of the battery charge status in unregulated, direct drive setups. IMHO, before any conclusions can be drawn, there needs to be at the very least, a controlled delivery of voltage and current to a given bulb from which photometry measurements are taken. My question of possibly making your results fit to the inverse square law were taken from the last text highlighted in red below.



mudman cj said:


> I took new measurements of the 1185 in my KT4 head using a new data reduction technique and I came up with a Lux value of 54,000. *I think the main reason for my low reading the first time was because the batteries were less charged. *
> 
> Also, using the method I describe in this new post, I would like to refine my lux measurement for the 1185 in the FM3X head to 117,000 lux. *The batteries are not quite as charged up as they were when I took my first measurement, but I can be more sure of this result because it is an average of many readings taken at different distances and then fit to the inverse square relation*.
> 
> At any rate, I think it is fair to say that the FM3X head with VLOP reflector doubles the lux for the 1185 bulb.



I have thought about all that would be involved in bringing the kind of rigor that old member "Newbie" used to deliver, especially with the quality regulated drivers from JimmyM and AlanB, but there is waning interest in incan setups to make it worth the time and effort. 

Ultimately, I have decided that practical visual appearance trumps most instances of [seemingly] rigorously controlled numerical results. As I said earlier, very few people who toss around lux/lumen/candlepower claims have a correct background understanding or willingness to learn it. 

For those that do have such a background, I have seen what I consider silly reports of millisecond peak output/startup or other uncontrolled photometer readings that people now accept as absolutes. Almost no one questions any of the variables I see that has me also question many of those results...but that thread is not what I would call "open for discussion."

People want to accept an absolute 'Truth' in many of these threads, especially when the OP claims that very ground by stating "truth is truth." Some of this is human nature because it is hard to "sit with uncertainty," and many people are intellectually lazy. They are perfectly happy if they have a 'seeming certainty,' that prevents having to do any real [or further] thinking and questioning of validity. 

My starting view on most issues is to assume less truth exists than is being represented, ask questions, and look at other aspects & deeper into the matter to see if the claims hold up. That can be a blessing and a curse.


----------



## Patriot (Sep 28, 2009)

*Re: I love the 1185 in the FM3X head!*



I came to the light... said:


> Patriot, mine appears to be most similar to the third type. It looks like that would reduce output but increase throw... ?



By third type I'm guessing you mean the 3rd pic down that's the most frosted looking? That would result in less overall lumen output and decreased throw as compared to the first reflector. 

Consider the bulb lumens a fixed constant with either reflector extreme (theoretically). The only effect remaining is higher or lower reflectivity. Higher reflectivity is allowing more photons out the front because of less reflector absorption. Lower reflectivity is allowing fewer photons out the front because of greater reflector absorption. The more dull and frosted the reflector the less the output and throw (peak lux). The only thing the more frosted reflector accomplishes is the smoothing out of the beam. It will cancel out the image of the irregularly focused and defocused point source of light, in this case, a filament.


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## Patriot (Sep 28, 2009)

*Re: I love the 1185 in the FM3X head!*



I came to the light... said:


> OK, I just took some more measurements, and converted to 1m using the inverse square law. Batteries were down to 4.01-4.03v this time.
> 
> 1m: 41,000
> 2m: 11,000.....->....44,000 at 1m
> ...









> *mudman cj
> *
> But, there is something potentially interesting in your data since the readings increase from 1 to 4 meters but then decrease at 5 meters. This could be due to a decrease in output as the batteries drain (assuming this point was measured last), or possibly just measurement variation.







Not to over simplify a very complex matter, but *I came to the light's* results are actually very typical using the inverse square law. With larger reflectors the effect is even greater in that the distance to peak lux is farther than 5m. When measuring lux from a 9" spot for example it's closer to 18 or 20 meters, (halogen spot) last time I was informally messing around with the figures.


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## mudman cj (Sep 29, 2009)

*Re: I love the 1185 in the FM3X head!*

With respect to the KT4/FM3X comparison, I did not describe the battery state of charge sufficiently. My first set of measurements using the KT4 in which I got the lower reading, was done with the batteries about 1/2 charged. After recharging, I first obtained the KT4 readings and then without recharging I obtained the FM3X readings. So, if anything the FM3X readings are comparatively lower than they would be had I used a constant current source to control the 1185 output level. 

When I stated that the data was fit to the inverse square relation, what I meant was that the data was a fit to the inverse square relation. That subtle distinction is important because the first statement implies that I somehow changed the data to make it fit an expected result. The reality is clearly shown in the other thread by both the raw data and graphs in which I fit the data using a least squares fit power equation and remove data points that lie off of the line due to the inherent errors of attempting to quantify the light intensity out of a reflectored light source at close distances. The remaining data points happen to follow the inverse square relation independently of whether I want them to or not.


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## get-lit (Sep 29, 2009)

*Re: I love the 1185 in the FM3X head!*

Patriot had directed me here to chime in regarding the relations of reflector dimensions to candlepower and throw distance.

A parabolic reflector's ability to produce candlepower is based upon it's ability to collimate, it's ability to gather light, and it's reflectance. There's a lot of useful information about this in on the Nightsword thread in the HID section. The relation of candlepower to throw distance is dependent upon the inverse square law, where the illumination in foot-candles or lux at any throw distance is the candlepower divided by the distance squared.

Although the relation of candlepower to throw distance is dependent upon the inverse square law, the relation of a reflector to candlepower is a direct factor of collimation, light gathering, and reflectance. Collimation is the inverse relation of the reflector focal length to the size of the luminance area. As the focal length increases in relation to the size of the luminance area, the entire parabola increases in size in relation to the luminance area, and more of the light closer to the edges of the luminance area are reflected at the angles needed to collimate the light. Therefore, if you double the focal length, you double the collimation for a given luminance area and likewise, double the candlepower. The inverse square law is then applied to the throw distance. Likewise, if you half one length of the luminance area, you also double the collimation. If you condense the same amount of luminance into that smaller luminance area with half a length, you also double the candlepower.

Collimation Factor = focal length / luminance length

as well as...

Collimation Factor = focal length / luminance area^1/2

With a parabolic reflector, candlepower is a direct factor of collimation and likewise focal length.

As you increase the size the parabola by increasing the focal length, you also increase the diameter of the reflector. For instance, if you double the focal length, you also double the reflector diameter, as well as the length, and light gathering has not been affected. But if you want to increase the focal length while keeping the reflector relatively the same overall size, you have then reduced light gathering. This is the case for all parabolic light designs and for a known luminance pattern, there is always a calculable point at which the trade off between gains through focal length and gains through light gathering are optimized. Please refer to post #114 in the Nightsword thread. 

*So focal length, light gathering and reflectance are all direct factors to candlepower, and in turn, they are an inverse square relation to throw distance just as candlepower is.*


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## Patriot (Sep 29, 2009)

*Re: I love the 1185 in the FM3X head!*

Thanks Get-lit for stopping by. I was always under the impression that the inverse square law applied to both point sources of light and point sources in conjunction with reflector, the idea being that once you were at sufficient distance the reflector is measured like any other point source of light. That seems to be the theme that I find in various web sources where the inverse square law is still applies, even when electromagnetic spectrum sources of energy are collimated, and I see that you also apply the law in your calculations. Honestly, I still don't have a robust understanding but I'm gleaning what I can't from posts like yours and several other from this thread. 
Thanks again :twothumbs





> *mudman cj*
> The reality is clearly shown in the other thread by both the raw data and graphs in which I fit the data using a least squares fit power equation and remove data points that lie off of the line due to the inherent errors of attempting to quantify the light intensity out of a reflectored light source at close distances. The remaining data points happen to follow the inverse square relation independently of whether I want them to or not.


When not in a science lab, this method is good enough for obtaining general results in my opinion. Sure, the first test was too close but all you were trying to do was to get a relative idea....was it 10%, 50%, or a 100% higher lux? As it turns out, it's close to double, which when I compare a 3" LOP FM head to a frosty KT4 is close to what I'm seeing also. 

At 16.4 feet I'm getting the below reading from various KT4 heads (rounded off)

42,800 
46,500
51,000



During quick checks at 8 & 10 meters. The readings seemed to also follow the inverse square rule in that the peak lux was always within 10-15% of all the values as a whole. In any case, this has been a good thread with a lot of good resource material.

I'll be off to Lux Luthor's reflector testing thread in an attempt to absorb some of the data I missed there the previous time. 

lovecpf


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## LuxLuthor (Oct 7, 2009)

*Re: I love the 1185 in the FM3X head!*



get-lit said:


> A parabolic reflector's ability to produce candlepower is based upon it's ability to collimate, it's ability to gather light, and it's reflectance. There's a lot of useful information about this in on the Nightsword thread in the HID section. The relation of candlepower to throw distance is dependent upon the inverse square law, where the illumination in foot-candles or lux at any throw distance is the candlepower divided by the distance squared.
> 
> Although the relation of candlepower to throw distance is dependent upon the inverse square law, the relation of a reflector to candlepower is a direct factor of collimation, light gathering, and reflectance. Collimation is the inverse relation of the reflector focal length to the size of the luminance area. As the focal length increases in relation to the size of the luminance area, the entire parabola increases in size in relation to the luminance area, and more of the light closer to the edges of the luminance area are reflected at the angles needed to collimate the light. Therefore, if you double the focal length, you double the collimation for a given luminance area and likewise, double the candlepower. The inverse square law is then applied to the throw distance. Likewise, if you half one length of the luminance area, you also double the collimation. If you condense the same amount of luminance into that smaller luminance area with half a length, you also double the candlepower.
> 
> ...



GL, I have read this post at least a dozen times, thought about various aspects and questions, read other resources, but I am still not understanding or able to reconcile all the points you are making. I am not sure if it is because I don't have an adequate background, or if you have not explained it adequately to make sense, or something perhaps not fully appertaining to this discussion. 

One of my difficulties rests with your using "luminance length and area," in ways that imply a relatively simple, point luminance source within the reflector. I am not able to visualize that with the complexity of a 3-dimensional tubular or spherical bulb envelope, within which is another specifically designed filament (transverse, axial, thin/thick, multi-coiled interwoven/single coiled radiator shaped, etc.) that together give a unique light output with some degree of artifacts into various aspects of a nearly spherical 360 degree environment. 

Then there is the issue of which part of the length of the bulb/filament is used for your focal length position measurement inserted at some distance within the parabolic reflector. 

Do you have some references you used to arrive at this information so I can deepen my understanding and definition of some of the terms you are using? Thanks!


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## fareast (Oct 8, 2009)

*Re: I love the 1185 in the FM3X head!*

Thank you all for this very interesting thread :thumbsup:! I have much, _much more_ reading still to do.


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## get-lit (Oct 9, 2009)

*Re: I love the 1185 in the FM3X head!*



LuxLuthor said:


> GL, I have read this post at least a dozen times, thought about various aspects and questions, read other resources, but I am still not understanding or able to reconcile all the points you are making. I am not sure if it is because I don't have an adequate background, or if you have not explained it adequately to make sense, or something perhaps not fully appertaining to this discussion.
> 
> One of my difficulties rests with your using "luminance length and area," in ways that imply a relatively simple, point luminance source within the reflector. I am not able to visualize that with the complexity of a 3-dimensional tubular or spherical bulb envelope, within which is another specifically designed filament (transverse, axial, thin/thick, multi-coiled interwoven/single coiled radiator shaped, etc.) that together give a unique light output with some degree of artifacts into various aspects of a nearly spherical 360 degree environment.
> 
> ...


 


Collimation ability is solely determined by the relation of the parabolic reflector focal distance and the lamp luminance area. Longer focal distances enlarge the size of the reflector in relation to the luminance area, which in turn decreases the overall angle of incidence to the target, thus increasing collimation. Relative candlepower is then a factor of the amount of light contained within that luminance area by the relative collimation, and also by the percentage of light gathered by the reflector.

When making relative comparisons with the same lamp types, calculating the shape of the luminance area is not necessary because the shapes are the same for lamps of the same type and only the size changes, so you can make comparisons with just the luminance area specs provided by the lamp manufacturer. For instance, for Xenon short arc lamps, the arc shapes are in the form of an egg shape within those dimensions, with a peak intensity near the large lobe. That is the point to center in the focus. The luminance area of AC short arc lamps like UHP lamps have two lobe ends and the arc shape is in the form of two opposing egg shapes that are joined in the middle.

Here's a decent article for learning a bit more about the inverse relation of luminance area to focal length to produce collimated light output, and in this article Etendue is the key term you want to review:
http://thomann.net/uhp.pdf

In that article, there are many sections describing the Etendue effect, and section 3.4 about arc length is particularly useful.

Here's more about Etendue:
http://en.wikipedia.org/wiki/Etendue

Although the formulas become complex, the concept is really quite simple. To produce the most candlepower, we want the the optical system to produce the most photons going the same direction. If we reflect an infinitely single point source of light with a perfectly parabolic reflector, we would have perfectly collimated light, and candlepower would simply be the amount of light emanating from the point light source. But since an infinite point source of light is impossible, we always have imperfect collimation because photons emitted further from the focal point are never perfectly collimated, and it is impossible for any reflector shape to perfectly collimate photons emitted from different points. As the size of the luminance area continues to increase, more and more photons emit further from the focal point and those photons divert further and further from collimation. If we then increase the focal length of the parabolic reflector, we increase the size of the parabola, which proportionately decreases the diversion of the photons that are further from the focal point.

Please refer to the following diagram:







In the diagram, the blue rectangles are the luminance area. The orange lines are the collimated light from photons emitted at the focal points of the parabolic reflectors. The blue lines are the diverted light from photons emitted at the opposite end of the luminance areas furthest from the focal points. The green lines are the extent of the angles from the luminance area captured by the reflector.

With optical system "A" as a reference, Optical system "B" has double the luminance area, and with the same focal length reflector, double the diversion.

Optical system "C" also has double the luminance area of system "A", but system "C" has also double the focal length of system "A", so the net effect on collimation is nil, and they collimate with exactly the same amount of diversion. System "C" is simply larger in relation to system "A", both the luminance area and the focal length are double in size. Divergence is the same because scaling size does not affect divergence angles.

But if you look at the green lines for system "C", you will also notice that it is capturing less of the angles from the luminance area. It now has less "light gathering" than both "A" and "B". The extent of this amount is dependent upon the luminance distribution pattern of the luminance area.


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## I came to the light... (Oct 12, 2009)

*Re: I love the 1185 in the FM3X head!*

There's been a lot of intelligent input in this thread, and I've learned a lot, and affirmed a lot of what I've suspected. But I'd like to bring this back to the reality of actually giving a significant measurement of the throw of a flashlight. 

First a quick question for get-light, or anybody else who knows the answer. Just out of curiosity, does candlepower include all light in a certain direction, or just the light in a certain direction in a certain area (1 steradian I believe)?

I came up with a theory regarding the inverse square law that turned out to be inaccurate, but I've summarized here because the resulting formulas did more accurately predict results. The theory is that at the point that the light exits the flashlight the beam has a certain angle of divergence, which can be traced back to a theoretical point source a certain distance behind the actual source. Therefore, the light should obey the inverse square law as if it were coming from that source (lux = a * (distance - b) ^ -2). Here's a very quick paint drawing to illustrate this point: 






I decided to test that theory with two flashlights. I retook the Megalennium data much more carefully than my previous measurements, and at a different charge level (which should not matter because it is only being compared to itself). To correct for the declining output of the Megalennium I remeasured lux at 1m at the end of the testing, and corrected all measurements by a fraction of the percent difference, making the necessary but slightly inaccurate assumptions that I took an equal amount of time between each measurement and that the output declined at a constant rate. 

The second flashlight tested, a Barbolight T14, is regulated, so no correction was made. 

This is the data at 1, 2, 3, 4, and 5m (unfortunately I don't have the space for longer range readings): 
Megalennium: 
1m: 35500
2m: 10100
3m: 4550
4m: 2710
5m: 1644

Megelennium corrected for end 1m reading of 34300:
1m: 35500
2m: 10171
3m: 4614
4m: 2767
5m: 1690


T14:
1m: 12680
2m: 3220
3m: 1400
4m: 812
5m: 517

Using the formulas generated by the inverse square law and the lux reading at 1 meter, I calculated an average 12.61% error for the Megalennium, and 1.30% for the T14. The T14's data is very accurate, but I'd like to see a bit more accuracy with the Megalennium. Presumably the difference in accuracies is mostly because of reflector size, and somewhat because of the imprecise output decline compensation. 

When I interpreted the data with distance correction I got the formulas lux = 47092.32 * (x + 0.1517) ^ -2 for the Megalennium, and lux = 13084.77 * (distance + 0.0158) ^ -2 for the T14. These have an average error of 1.80% for the Megalennium, and 0.69% for the T14. This is significantly more accurate, and more importantly there is less of a difference due to reflector size. However, I'm sure you noticed that the differences are in the wrong direction, too small, and nearly identical (I used many more decimal places in my calculations, so they may have been identical, I'm not sure). It seems that although this correction does help, it does so by virtue of introducing another variable, and that the theory is incorrect. 

In conclusion, my revised and additional data supports the inverse square law to reasonable accuracy, and the correction formula helps a lot, although the results don't make sense. Hopefully somebody else cares to further test this with their own data? Most importantly, it would be most helpful if somebody could test this at longer ranges.


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## get-lit (Oct 13, 2009)

*Re: I love the 1185 in the FM3X head!*



I came to the light... said:


> ...does candlepower include all light in a certain direction, or just the light in a certain direction in a certain area (1 steradian I believe)?


 
Although candlepower is the intensity of light in a single direction and a single direction inherently means the unit is area-less, we have to relate to and measure the unit as the amount of light per area at distance squared:

CP = lumen/Area x Distance^2

If we're measuring in feet:

CP = lumen/(foot x foot) x (foot x foot)

If we're measuring in meters:

CP = lumen/(meter x meter) x (meter x meter)

But, this can be reduced to:

CP = lumen

That's because unit itself is area-less as it is only a relation. As a unit of measure it is not of any quantitative use which is why it's now deprecated.


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## get-lit (Oct 13, 2009)

*Re: I love the 1185 in the FM3X head!*

Now regarding your hypothesis, the point behind the reflector is actually the virtual focus point for a "hyperbolic" reflector, but hyperbolic reflectors do not apply here because we use parabolic reflectors. Hyperbolic reflectors generate "diverged" light from a focus point in front of the reflector as if emanating from the virtual focus point behind the reflector. On the other hand, parabolic reflectors generate "collimated" light from a focus point in front of the reflector without a virtual focus point behind the reflector. But, your suggestion has sparked something very interesting. Since Etendue is essentially a measure of divergence as a relation of the focal length of a "parabolic" reflector to the focal area within it, and since the distance to the virtual focal point behind a "hyperbolic" reflector is also essentially a measure of divergence, then we could also say that a "parabolic" reflector with a real focus area is also a "virtual hyperbolic" reflector with a virtual focus point at a distance defined by the reflector Etendue!!! That is so interesting because we now have a real relation between a "real focal area" to a "virtual focal point". That's awesome!



Remember that our goal is in acheiving as close as we can to absolute collimated light from an absolute point source of light, which both are impossible infinities. Having an absolute point source of light with absolute collimation from a parabolic reflector would be just like having a hyperbolic reflector with infinite focal length.

This discussion should have it's own thread. Heck I don't even know what an 1185 or FM3X is!


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## LuxLuthor (Oct 13, 2009)

*Re: I love the 1185 in the FM3X head!*



get-lit said:


> This discussion should have it's own thread. Heck I don't even know what an 1185 or FM3X is!



LOL! Finally, I got something on ya! 

1185 is a small Welch Allyn bulb (click destructive testing link in my sig). FM3X is a 3" head sold here. Not sure if FM is using Carley or his own source to make the reflectors.

I'm still reading and thinking about your other posts.


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## I came to the light... (Oct 13, 2009)

*Re: I love the 1185 in the FM3X head!*

I just realized that I represented the accuracies redundantly (inaccurately) - I wrote them as a ratio over 1, and also added a % sign. I've fixed that, and also rewrote some of the data interpretation to make it more clear. 

get-lit, thanks for explaining. But it sounds like the final result still incorporates direction and an unknown constant, so it isn't mathematically equal to lumens. Anyway, I think I'll stick to lux and lumens now, concepts which I understand quite well, and are not deprecated 

If I'm reading your second post correctly, you're saying that the formulas should in fact continue to be accurate over longer distances because the displacement I found does in fact indicate a virtual focus point? 

Also, I'd like to point out that most flashlight reflectors are not perfectly parabolic, or even close enough to negligibly affect light dispersion. But it seems that the facts you stated would say that this virtual focus point, and therefore the corrected formulas, still apply, correct? 

BTW get-lit, I've been looking at your HID project, and wow! I'm really looking forward to seeing the results. It's rare that you see such a high goal sought by a person skilled enough to achieve it.


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## get-lit (Oct 14, 2009)

*Re: I love the 1185 in the FM3X head!*



I came to the light... said:


> If I'm reading your second post correctly, you're saying that the formulas should in fact continue to be accurate over longer distances because the displacement I found does in fact indicate a virtual focus point?


 
I haven't reviewed your calculations, but the virtual focus point is a common optical property that's typically used for this purpose.



I came to the light... said:


> Also, I'd like to point out that most flashlight reflectors are not perfectly parabolic, or even close enough to negligibly affect light dispersion. But it seems that the facts you stated would say that this virtual focus point, and therefore the corrected formulas, still apply, correct?


 
Yep. In fact I would say that any light focusing optic with divergence performs as a virtual hyperbolic function with a focal point. And since all light focusing optics have divergence, I guess I would even say that all light focusing optics perform as a virtual hyperbolic function with a focal point.



I came to the light... said:


> BTW get-lit, I've been looking at your HID project, and wow! I'm really looking forward to seeing the results. It's rare that you see such a high goal sought by a person skilled enough to achieve it.


 
Thank you.


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## I came to the light... (Oct 14, 2009)

*Re: I love the 1185 in the FM3X head!*

Thanks for all your input get-lit. My goal in this was to find a reasonably accurate formula for throw distance of a flashlight, and it looks like the inverse square law with an x offset provides meaningfully accurate results. 

One last factor remains to be determined, and I think the readers of this thread may know a bit about it - how to define maximum throw distance in terms of lux. I would prefer to leave factors such as beam interference out of this, since I doubt they make much difference, they are varied too much by the atmosphere, and they would be staggeringly complicated to account for. The standard seems to be 1 lux. But, are objects really visible at 1 lux? I have no way of knowing. 

I followed get-lit's suggestion and started a separate thread, oriented more towards the implementation of the theory than the theory itself. https://www.candlepowerforums.com/threads/245138


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## get-lit (Oct 15, 2009)

*Re: I love the 1185 in the FM3X head!*

The standard throw specification I've seen for high power search lights is the distance to which the light can illuminate 1 lux. I'd definitely go with that. I wish all throw measurements were this standard instead of candlepower.


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## I came to the light... (Oct 15, 2009)

*Re: I love the 1185 in the FM3X head!*



get-lit said:


> The standard throw specification I've seen for high power search lights is the distance to which the light can illuminate 1 lux. I'd definitely go with that. I wish all throw measurements were this standard instead of candlepower.



OK, that sounds like a good idea. It also gives results similar to advertised ratings, depending on the company.


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## mudman cj (Oct 18, 2009)

Check out the outdoor beamshots I took with the help of Socom1970. Thanks Jordon! It was a good time as always. 

Edit: The beamshots were added to the first post of this thread.


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## Dioni (Oct 18, 2009)

Thanks. The beamshot are great!


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## LuxLuthor (Oct 19, 2009)

mudman cj said:


> Check out the outdoor beamshots I took with the help of Socom1970. Thanks Jordon! It was a good time as always.



Linky Dink?


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## LuxLuthor (Oct 19, 2009)

*Re: I love the 1185 in the FM3X head!*



get-lit said:


> The standard throw specification I've seen for high power search lights is the distance to which the light can illuminate 1 lux. I'd definitely go with that. I wish all throw measurements were this standard instead of candlepower.



Have you seen the method described in the NEMA standard? I believe it will include my concerns you summarized in the etendue posts & diagrams above.

I still have questions I have not been able to resolve even after looking at your useful diagrams in post #48, and reading a dozen sources on etendue. I am not sure how to evaluate the surface area of bulbs such as the Philips DL-50, or the tubular MaxaBeam short arc bulb where their tubular envelope is parallel with the collimation output, vs. what appears to be a perpendicular drawing in your post #48.

It is interesting to examine the different reflector shapes and position of bulb filament or arc gaps in various spotlights (XeRay, MaxaBeam, generic spotlights, and various maglite mods). I can see this is a very complex subject once you start including all the variations in light sources and reflector configurations.


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## Billy Ram (Nov 15, 2009)

After reading through this interesting thread it got me in the mood to experiment. Last night I took my m*g85 and installed my FM3X VLOP head. I also installed my Throw master 2.5 VLOP head on my m*g458 and went out side. Right off the m*g85 was giving off a larger and brighter spill with the FM3X head over the TM 2.5 head that has been on the light. It was just plain giving out more light but the throw wasn't quite the same. Also it had bat wings. I didn't like the TM 2.5 heads too well on the m*g458. It didn't help the throw and seemed to cut back the spill. Some one wanting more spill and don't mind bat wings the FM3X will be the trick but the TM 2.5 seems to work well with the 1185 bulb and will out throw the FM3X. Right now my m*g85 with the TM 2.5 head will also out throw my m*g458 a little bit. I believe the 64458 bulb needs to extend a bit farther into the reflector but its legs are too short. I have mine just far enough in the holder to get a grip with the set screw and getting one centered is tricky. "I broke one bulb"
Billy


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## fivemega (Nov 15, 2009)

Billy Ram said:


> I didn't like the TM 2.5 heads too well on the m*g458. It didn't help the throw and seemed to cut back the spill.
> Billy



*Beam shape, hot spot, spill and throw are products of reflector shape reflector size, texture AND fillament size/shape.
Axial fillaments are good for larger hot spot and not suitable for throw even if used with large SMO reflector.
For more concentrated hot spot not only you need large/SMO reflector, you will also need transverse small fillament bulb and remember, textured reflectors smooths out the beam artifacts at cost of throw.

Now, back to original topic.

Who else loves the 1185 in the MOP FM3X head?
Who else loves the 1185 in the VLOP FM3X head?
Who else loves the 1185 in the SMO FM3X head?*


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## mudman cj (Nov 15, 2009)

Wow, I am surprised that the 2.5 inch TM head out-throws the VLOP FM3X head with the 1185. I don't have a TM, so I have to take your word for it. Is the TM SMO or deeper? What is a likely explanation for the difference? 

My hotspot is already pretty small with the FM3X the way I have it focused. If the TM head makes the hotspot even smaller then I wonder if I would like it as much. :thinking: How much difference in throw would you say there is between the two options?


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## Billy Ram (Nov 15, 2009)

mudman cj said:


> Wow, I am surprised that the 2.5 inch TM head out-throws the VLOP FM3X head with the 1185. I don't have a TM, so I have to take your word for it. Is the TM SMO or deeper? What is a likely explanation for the difference?
> 
> My hotspot is already pretty small with the FM3X the way I have it focused. If the TM head makes the hotspot even smaller then I wonder if I would like it as much. :thinking: How much difference in throw would you say there is between the two options?


 I don't believe the TM head is deeper than the FM3X but it compliments the 1185 bulb. My TM head is VLOP and with the 1185 bulb I get a rounder more intense hot spot than with the FM3X VLOP. The FM3X head seems work better with the axle filament bulbs on my m*g458 producing a very round but larger hot spot. 
billy


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## fivemega (Nov 15, 2009)

Billy Ram said:


> I don't believe the TM head is deeper than the FM3X but it compliments the 1185 bulb.
> billy



*FM3X has same parabola of standard 2" reflectors and 2.5" Throw Master has deeper parabola but not as deep as 2" deep reflectors.*



fivemega said:


> How about a CNC machined aluminum 2.5" hard anodized turbo head with removeable cam deep reflector, Boro lens, crenelated bezel available in red, gun metal gray, green, black or chrome plated *only*. Best of all will fit and function in M*g "D", M*g "C" and *FM11/FM85*. No adapter needed.


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