scout24
Flashaholic
Ever gracious, Hogo. Despite the best efforts of others... :kiss:
HDS Systems EDC # 19
- Thread starter nbp
- Start date
Help Support Candle Power Flashlight Forum
- Status
eraursls1984
Flashlight Enthusiast
I think all of the numbers are useful if you just compare each person's findings with their previous results, and not so much comparing from reviewer to reviewer.
Btw Hogo, I have two ellipses connected to a highly sophisticated neural network for testing lights. If you donate a 4000K Nichia 219C HDS I can test it for you. I have a 4000K XP-L HDS that I've tested. The results from the 4000K XP-L; Good, real real good.
Btw Hogo, I have two ellipses connected to a highly sophisticated neural network for testing lights. If you donate a 4000K Nichia 219C HDS I can test it for you. I have a 4000K XP-L HDS that I've tested. The results from the 4000K XP-L; Good, real real good.
tech25
Flashlight Enthusiast
LOL!!!:laughing: I have the same testing apparatus!! You can send the XP-L to me to confirm your results...
Hogokansatsukan
Flashlight Enthusiast
I have the same setup but it's getting old and outdated.
PMed maukka with my offer (he will get a couple free lights with testing data so he can calibrate his sphere to actual numbers).
Me+Light=Addiction
Enlightened
My HDS collection
Last edited:
jon_slider
Flashlight Enthusiast
- Joined
- Mar 31, 2015
- Messages
- 5,190
HOGOKANSATSUKAN said:
pics! or it did not happen.. LOL
(please no single beam shots, use multiple samples, as below, to compare relative tint)
congratsMy HDS collection
how about some side by side beam shots?
something like this
LtoR 3000k XPL, 4000k N219b, 4500k N219b, 5000k N219b
Last edited:
Hogokansatsukan
Flashlight Enthusiast
My HDS collection
Looks like you need a holster that holds 4! LOL
So maukka and I have been conversing through email, and we are going to make this happen. We agree it will help the community here to verify and validate data. Don't think for a minute that I don't read these reviews! Of course I do... I'm an addict... and it costs me daily$$$$
I trust the reviews more than I trust what the manufacturer says... even Nichia. The only exception is HDS because I have often been there doing the calibrating and testing in the past. Novatc, when in Tucson, I trusted because I was the poor schmuck putting every light in a sphere and testing it in the middle of the night... after they left Tucson... nope.
Independant testing is important, and the more accurate we can make it, the better off we all are.
Last edited:
Me+Light=Addiction
Enlightened
congrats
how about some side by side beam shots?
something like this
LtoR 3000k XPL, 4000k N219b, 4500k N219b, 5000k N219b
Good idea, i'm gonna try to make some good photo's when it gets dark!
Me+Light=Addiction
Enlightened
I know right, that would look cool. Just for show though, but still looks cool!
I'm really liking the holster and i'm using it a lot more than I expected it to which is really nice.
It's the perfect way to carry a rotary at all times.
recDNA
Flashaholic
- Joined
- Jun 2, 2009
- Messages
- 8,761
Saved me going over budget. Hate the green tint
Me+Light=Addiction
Enlightened
Oke, so I did my best... I tried with different brightness and backgrounds. Single lights and multiple lights and it was super difficult getting the colour decent to what it is for real.
Now for the confusing part, light number 2 and 4 look decently close to reality, however, for some odd reason you have to switch the beams on light 1 and 3.
Beam 1 is closer to light number 3 (although too purple on the picture) and beam number 3 looks more like the real beam coming from light number 1 !!!
A bit odd but I couldn't make those lights bring out their own colour. Played with my phone settings but to no avail!
From left to right: (1)HDS 5k 219c (200 lumens), (2)HDS 4k (XP-L?, the special run with 325 lumens anyway!), (3)HDS 325 Tactical (325 lumens), (4)HDS LE Clicky (200 lumens of cool white light)
So remember, the HDS 5k beam colour looks more similair to the beam of light number 3 shown in the picture and vica versa!
The one that is LEAST representative of reality is the HDS tactical, it's not purple at all. When put on paper it shows hints of purple but in reality it's a nice neutral colour.
Now for the confusing part, light number 2 and 4 look decently close to reality, however, for some odd reason you have to switch the beams on light 1 and 3.
Beam 1 is closer to light number 3 (although too purple on the picture) and beam number 3 looks more like the real beam coming from light number 1 !!!
A bit odd but I couldn't make those lights bring out their own colour. Played with my phone settings but to no avail!
From left to right: (1)HDS 5k 219c (200 lumens), (2)HDS 4k (XP-L?, the special run with 325 lumens anyway!), (3)HDS 325 Tactical (325 lumens), (4)HDS LE Clicky (200 lumens of cool white light)
So remember, the HDS 5k beam colour looks more similair to the beam of light number 3 shown in the picture and vica versa!
The one that is LEAST representative of reality is the HDS tactical, it's not purple at all. When put on paper it shows hints of purple but in reality it's a nice neutral colour.
Last edited:
archimedes
Flashaholic
....
....
Wow ... quite a spectrum of light there, Roy G Biv :huh: (lol)
Last edited:
HDS_Systems
Enlightened
Allow me to explain why integrating spheres are way more problematic then you understand...
First, it is important to understand that the definition of a lumen includes a very specific spectral response. The spectral response corresponds to the sensitivity curve of the human eye - or at least the small group of young people who's test data was used to generate the curve. Thus green light makes the largest contribution because it is at the peak of the curve. Blue and red light make much smaller contributions because they are near the ends.
Second, we have the sensor. Less expensive devices, such as the light meters used in photography and low end integrating spheres, have a single light sensor. The sensor itself has a spectral response - i.e., it is more sensitive to certain parts of the spectrum. To fix at least part of this problem, a special filter with a different sensitivity curve is placed in front of the sensor. The hope is that the combined sensitivity curve will approximate the required lumen sensitivity curve. Although really good filters have been created in the lab, they are generally too expensive to use in practical instruments. As a result, there can be significant differences between the lumen curve and the filtered sensor curve and those differences will result in signficant errors that cannot be removed from the system. Higher end meters often include compensation tables that are keyed to different light sources in an attempt to provide better results. That's because if you change the spectral content, you directly affect the accuracy of the reading.
For truly accurate results, we must use a spectrographic sensor system. This system splits light into its component parts from say 360nm to 850nm in very narrow bands. Each band may be only 1nm wide and has its own sensor. There are no filters and thus no inherent filter errors. A spectrographic sensor system is also needed for measuring color temperature, color rendering index calculations, spectral graphs and the like.
Third, we have the integrating sphere itself. The sphere is designed to scatter light uniformly across the surface with the minimum of losses and no additions. The surface must be coated with a highly efficient diffusing material that has no florescent characteristics. The sphere also provides a port that only views a piece of uniformly scattered light. The sensor is never allowed to see the primary light source or a direct reflection of the primary light source.
Finally, there is the NIST-tracable calibration system. This system injects a known amount of light with a known spectral content into the sphere. Each sensor is adjusted (scaled) so the final output exactly matches the known light source. A dark set of data is also taken so that sensor noise can be removed from the data.
The "lamp under test" must be included when you calibrate an integrating sphere. The bezel, reflector, LED and anything else that the sphere can see will directly affect the results. All of these items must be accounted for during the calibration process. Want to test a different type of flashlight? Or test one with a different bezel color? Or test one with a different LED? Then recalibrate the integrating sphere. Yes, it is a lot of work. But if you want accurate results, you have to do it.
So let's return to homemade spheres. It should now be clear how difficult it will be to get an accurate result. I built an integrating sphere long ago and put a lot of time into it. I did the calculations and came at things from very different directions to try and remove errors. When I got my NIST-tracable spectrographic integrating sphere, the first thing I did was to compare them. Sadly, the homemade integrating sphere was way off - even after all of that effort. So now, perhaps, you have a much better idea of how difficult it is to get good light measurements.
Henry.
First, it is important to understand that the definition of a lumen includes a very specific spectral response. The spectral response corresponds to the sensitivity curve of the human eye - or at least the small group of young people who's test data was used to generate the curve. Thus green light makes the largest contribution because it is at the peak of the curve. Blue and red light make much smaller contributions because they are near the ends.
Second, we have the sensor. Less expensive devices, such as the light meters used in photography and low end integrating spheres, have a single light sensor. The sensor itself has a spectral response - i.e., it is more sensitive to certain parts of the spectrum. To fix at least part of this problem, a special filter with a different sensitivity curve is placed in front of the sensor. The hope is that the combined sensitivity curve will approximate the required lumen sensitivity curve. Although really good filters have been created in the lab, they are generally too expensive to use in practical instruments. As a result, there can be significant differences between the lumen curve and the filtered sensor curve and those differences will result in signficant errors that cannot be removed from the system. Higher end meters often include compensation tables that are keyed to different light sources in an attempt to provide better results. That's because if you change the spectral content, you directly affect the accuracy of the reading.
For truly accurate results, we must use a spectrographic sensor system. This system splits light into its component parts from say 360nm to 850nm in very narrow bands. Each band may be only 1nm wide and has its own sensor. There are no filters and thus no inherent filter errors. A spectrographic sensor system is also needed for measuring color temperature, color rendering index calculations, spectral graphs and the like.
Third, we have the integrating sphere itself. The sphere is designed to scatter light uniformly across the surface with the minimum of losses and no additions. The surface must be coated with a highly efficient diffusing material that has no florescent characteristics. The sphere also provides a port that only views a piece of uniformly scattered light. The sensor is never allowed to see the primary light source or a direct reflection of the primary light source.
Finally, there is the NIST-tracable calibration system. This system injects a known amount of light with a known spectral content into the sphere. Each sensor is adjusted (scaled) so the final output exactly matches the known light source. A dark set of data is also taken so that sensor noise can be removed from the data.
The "lamp under test" must be included when you calibrate an integrating sphere. The bezel, reflector, LED and anything else that the sphere can see will directly affect the results. All of these items must be accounted for during the calibration process. Want to test a different type of flashlight? Or test one with a different bezel color? Or test one with a different LED? Then recalibrate the integrating sphere. Yes, it is a lot of work. But if you want accurate results, you have to do it.
So let's return to homemade spheres. It should now be clear how difficult it will be to get an accurate result. I built an integrating sphere long ago and put a lot of time into it. I did the calculations and came at things from very different directions to try and remove errors. When I got my NIST-tracable spectrographic integrating sphere, the first thing I did was to compare them. Sadly, the homemade integrating sphere was way off - even after all of that effort. So now, perhaps, you have a much better idea of how difficult it is to get good light measurements.
Henry.
the0dore3524
Flashlight Enthusiast
Thanks for the input Henry. Didn't read/understand all of it, but yeah got the idea.
archimedes
Flashaholic
Always a pleasure to hear from the expert in here
gunga
Flashaholic
Outstanding info. Thanks Henry!
indigon
Enlightened
Oke, so I did my best... I tried with different brightness and backgrounds. Single lights and multiple lights and it was super difficult getting the colour decent to what it is for real.
Thanks for the post.
My 5k 219c came looking like the third from the left out of the box. (to me).
When I added the Lee 1/4 minus-green filter most of the green was eliminated.
The filter is such a pale magenta most folks wouldn't notice it was there if I didn't tell them it was installed.
I like the tint a lot now, this is easily becoming my favorite HDS light with this filter installed.
Ron
neutralwhite
Flashlight Enthusiast
Thanks , have you got a picture of the tint with the lee filter on?.
What are these lee filters and where could I get one for the same light?.
how are they installed and used ?.
cost?.
thanks.
What are these lee filters and where could I get one for the same light?.
how are they installed and used ?.
cost?.
thanks.
indigon
Enlightened
This is absolutely true. Thanks for the insight.
In my testing I found out that the best thing you can do for your home made sphere is to diffuse the light at the input port. This also lessens the "light under test" error with the size of the reflector among other things affecting the integration. The throwy/floody aspect throws off most DIY spheres. Even if I use a spectrophotometer (which doesn't go down to 1nm bands), I would never claim an accuracy better than +-20% because all of the variables.
Now why can't I find a cheap Chinese sphere from Aliexpress...
- Status
