Actual Lumens readings in 6" dia. Lab Sphere IS with SC 5500 control

[Bullzeyebill]

dang! hmmmm, well I should edit my post, I meant a P91, as that's supposed to be 200 lumens...

Am I the only one that thinks the LF Rating is too high? that means that their 1000 lumen thing is only 800 or something...

Cheers,
Flash

LF has always used bulb lumens, not out the front lumens. They would never be able to give out the front lumens accurately as it depends on so many factors inherent in a given flashlight, such as type of reflector, type of glass used for window, built in resistance in flashlight, etc. They are not alone. Same with Welch Allyn, and Carley. The out the fron lumens with the 1000 lumen bulb would probably be in neighborhood of 650-700 lumens, dependent on a lot of factor. Spend some time in the incandescent forum. :thumbsup:

Bill

 

[flash_bang]

LF has always used bulb lumens, not out the front lumens. They would never be able to give out the front lumens accurately as it depends on so many factors inherent in a given flashlight, such as type of reflector, type of glass used for window, built in resistance in flashlight, etc. They are not alone. Same with Welch Allyn, and Carley. The out the fron lumens with the 1000 lumen bulb would probably be in neighborhood of 650-700 lumens, dependent on a lot of factor. Spend some time in the incandescent forum. :thumbsup:

Bill

Thanks much!
I guess this means I need to shoot for 500 and get about 300.

Thanks again,
Flash

 

[MrGman]

I finally got more time on the IS. I brought my original Malkoff M60 and tested it with no bezel in the Solarforce host with 1 extension tube and 2X17500 batteries. I also remembered to set the controller for the sphere to fixed range so I could see the instantaneous turn on peak reading. M60 with no bezel in the way hit 276 lumens. Warmed up it dropped to 245 lumens. Put the non crenallated bezel on by Solarforce (also let it cool down for a couple minutes) and redid the test. Turn on peak was 240 lumens and it dropped to 215 at warm up.

That is basically a 12.2% drop due to that bezel, most of that is the non AR coated glass but some is the blackened bezel edge cutting off just a bit of light around the perimeter.

The data has been added to the front sheet as individual line items for Fooboy or anyway who wants to dump it into a spreadsheet.

 

[Bullzeyebill]

Would be interesting to see differences using a SF bezel setup with a UCL window, UCL should transfer more light than Pyrex/Borofloat.

Bill

 

[MrGman]

Would be interesting to see differences using a SF bezel setup with a UCL window, UCL should transfer more light than Pyrex/Borofloat.

Bill

Do you have one of these, is the glass available or is this something one has to buy as part of a SureFire Flashlight package? Give me all the details you can about this. Thanks, G.

 

[cfromc]

Do you have one of these, is the glass available or is this something one has to buy as part of a SureFire Flashlight package? Give me all the details you can about this. Thanks, G.

The pyrex is standard on most SureFire bezels (i.e. 6P, 6PD, C2, C3) made in the past 6-7 years while Lexan is standard on the G2/G2L and older 6P models (the change was around 2001/2002). The UCL glass is available at Lighthound.com here: http://www.lighthound.com/UCL-for-SureFire-G2_p_2254.html
and flashlightlens.com here: http://www.flashlightlens.com/str/index.php?app=ccp0&ns=display&ref=apps_specs

I think an excellent comparison would be on a G2/G2L window with the standard Lexan, vs. Pyrex vs. a UCL window. Most G2/G2L/6P bezels have a removable retaining ring so the Lexan can be taken out and replaced with Pyrex, then replaced with UCL.

 

[Bullzeyebill]

cfromc, good post.

Bill

 

[MrGman]

I asked the people at Lighthound if this would fit into the Solarforce Bezel and they said they would check with flash light lens and the answer was no. FLL doesn't have anything to fit directly into a SureFire 6P or Solarforce L2 host? I don't have any SureFire G2 hosts and I don't think the Bezel will screw onto my 6P or L2 hosts anyway if some one lent me one, is that correct?

I may have to get one of these UCL's and just see what I can do to make it fit my bezel. If its too big I can certainly make it smaller.

I would certainly like to get some that will just drop into the L2 Bezel though.

 

[naked2]

FLL does have one for the 6/9P, as well as one for the G2; they're different. The diameter is only very slightly different, but the thickness I think is much different. There's a third one of around he same diameter listed with no hosts; maybe it'll fit the L2, you'd have to measure yours.

 

[naked2]

OK, I just measured my L2 lens; it's 27.87mm diameter by 1.81mm thick. There's one listed as 28.6mm x 1.83mm; it should fit. Though there is a difference in it than the ones listed as for SureFires; it is listed as "UCL green tint AR" with 98% typical performance, and the SF ones are listed as "UCL blue tint AR" with 99%.

 

[43X16]

Thanks for posting, tremendous info!

 

[jenskh]

I have made some experimenting with my DBS with and without lens. The lens seems to reduce the illuminance in the hot spot by about 16 %, but it seems to make little difference in the total output measured in lumens.

I suggest this as a test also in the integrating sphere to find out how much the lens means. Just measure with and without lens. Afterwards we can find out which lens is best.

 

[Bullzeyebill]

I have made some experimenting with my DBS with and without lens. The lens seems to reduce the illuminance in the hot spot by about 16 %, but it seems to make little difference in the total output measured in lumens.

I suggest this as a test also in the integrating sphere to find out how much the lens means. Just measure with and without lens. Afterwards we can find out which lens is best.

There are some posted lumen figures for M60 with and without a lens (bezels removed).

Bill

 

[MrGman]

I have made some experimenting with my DBS with and without lens. The lens seems to reduce the illuminance in the hot spot by about 16 %, but it seems to make little difference in the total output measured in lumens.

I suggest this as a test also in the integrating sphere to find out how much the lens means. Just measure with and without lens. Afterwards we can find out which lens is best.

That size reflector is too big for the opening of the sphere that I have access to at work as I have pointed out in previous pages. I have measured as already pointed out the Solarforce Bezel and its plain glass in front of the Malkoff M60 to show that it causes about a 12% of total lumens loss. I figure about 8% from the glass and another 4% from the shadow effect of the black bezel itself. In all cases if you can get an AR coated lens or window to go in front of you favorite torch I would do it if you want peak lumens.

You can try your test again using the ceiling bounce method and get more of an average for the total loss of the lens you are using. Since it is a direct comparative process, absolute accuracy of the readings isn't critical, just that you measure both the same way. Put the light meter on table or some other surface above the floor, point the light at the ceiling from a fixed distance, like a table, put the lens in and out and find the difference in those readings. The closer to the ceiling the better. Don't confuse this for lumens, just know that you can see the difference and use it more of an overall average of the light loss than just the hot spot reading. Tell us what you find.

 

[MrGman]

I have done more testing specifically comparing bezel with glass to bezel with the glass removed. So rather than have no bezel at all, I simply took one of the crenellated bezel types, unscrewed the crenellation and took the glass and seals out. the bezel still holds the lamps in which was necessary this time because I decided to test the Lumens Factory ES-9 and the SureFire factory P60. So I am sure there is some slight shadowing effect of the bezel being there but we can compare directly to not having any glass versus non AR coated glass. Data is back on sheet #1 in Orange since its incandescents.

the ES-9 is the Energy Saver 9V from Lumens Factory rated at 150 bulb lumens probably running on an exact 9.0V power supply. With 2 freshly charged lithium ions I saw only a 5% loss due to the glass being in the bezel.

The SureFire P60 I had to test with primary batteries and I saw a 10% drop. I actually did the test with the glass installed first and then repeated with no glass, so if the batteries are already getting weak the second reading with no glass should not have been that much higher. I am at a loss as to why this is unless the sphere is again reading the differences in the actual reflectors adding to the total readings and the 2 units are not the same. All I can say is that the LF reflector looks shinier (more shine?) than the SureFire P60.

You may say, why didn't I do this on some LED modules instead. I am getting reading to help do a cross calibration with WBP on his 2 spheres to an incandescent light source that more closely represents "Illuminant A" that is normally used to calibrate integration sphere systems.

More to come.

 

[PhantomPhoton]

That's rather interesting that there's different apparent losses between the two incan modules. I look forward to more findings.

 

[jenskh]

That size reflector is too big for the opening of the sphere that I have access to at work as I have pointed out in previous pages. I have measured as already pointed out the Solarforce Bezel and its plain glass in front of the Malkoff M60 to show that it causes about a 12% of total lumens loss. I figure about 8% from the glass and another 4% from the shadow effect of the black bezel itself. In all cases if you can get an AR coated lens or window to go in front of you favorite torch I would do it if you want peak lumens.

You can try your test again using the ceiling bounce method and get more of an average for the total loss of the lens you are using. Since it is a direct comparative process, absolute accuracy of the readings isn't critical, just that you measure both the same way. Put the light meter on table or some other surface above the floor, point the light at the ceiling from a fixed distance, like a table, put the lens in and out and find the difference in those readings. The closer to the ceiling the better. Don't confuse this for lumens, just know that you can see the difference and use it more of an overall average of the light loss than just the hot spot reading. Tell us what you find.

Thank you for the tip on the ceiling bounce. Using this technique, I got a 6,5 % higher reading without the lens, which seems to fit in nice between your measurements and estimates.
I discovered that in the test mentioned in my previous post here, the battery was quite low for the test without the lens. I guess this was the main reason for my conclusion. Even that the DBS is well regulated, it is not totally independent on the condition of the battery.
I am getting more and more eager to get an UCL lens both for my DBS and my CL1H.

 

[Alan B]

We have a couple of Integrating Spheres at work in the lighting lab and I know the engineer that works with them. He mentioned to me some time back that for good readings they have to be recalibrated for each setup due to the reflectance of the different source. He said it is easy to do as the calibration lamp is always there. It is more important for their setup since they put the source under test entirely into the sphere (large sphere). But I expect the same is true here - each time a change is made to the lens, bezel, or reflector the system is changed and should be recalibrated. The more reflective the surface inside the sphere is the more important the losses in the flashlight under test become.

-- Alan

 

[wbp]

If you have a sphere with a built in reference lamp, you can recalibrate as you describe.

Note however, that the lamp in your sphere is most likely incandescent and also very likely Illuminant A. Depending on the instrumentation you are using this may result in inaccurate readings for LED's that have a very different spectrum. Most of the spheres that have been available until very recently used filtered sensors to approximate the CIE photopic measurement curves; such a system is only really accurate when measuring incandescent lights. Very recently the industry has started to use spectroradiometers for this purpose - these are more expensive but also much more accurate for devices such as LEDs.

We are working on establishing an LED reference more appropriate for our needs.

William

Radiometric spectrum of incandescent reference lamp in Hoffman LS-65-8C:

Radiometric spectrum of Spartanian S2 LED flashlight on Level 10:

 

[precisionworks]

PLEASE test the peak output of a P91 incan in a surefire host

In the testing I've done with my shop built IS, only one incan is easy to test - The A2 Surefire. Because it's regulated, the output stabilizes quickly & settles in so a relevant reading can be taken.

Every other incan produces a high initial reading that immediately starts dropping like a rock. Even if the tester picks some arbitrary time, like 120 seconds after turn on, the reading will still not be stable at that point. Since the human eye adjusts to the diminishing light level, it is not noticeable or objectionable, but it does make testing difficult.