We don’t. You would probably need to buy a big professional integrating sphere to get the best accuracy. That’s thousands of dollars. We are just hobbyists, so we have to accept a certain lack of accuracy to keep the costs reasonable.
The thing about the Texas_Ace Lumen Tubes is that they are all built the same, so even if it’s off, it’s off by the same amount for everyone. I think Dale’s lumen tube is one he built himself. It’s also bigger in diameter than my 3.5” TA Lumen Tube. Maybe there is something about the bigger diameter that changes the response curve at higher output levels? I’m not sure. I’m also not too concerned about it. I know Dales heavily modded SP70 is not actually doing double the lumens of mine. It’s a bit brighter because he’s pushing the led harder, but not double the lumens.
I did not make my light box, as I’ve said many times, even just a couple of posts above…
“971.6M throw Jason. Based on a 30 second 236Kcd reading. And yes, my lightbox is calibrated with Maukka lights, the same pair of lights that Robo819, TomE, Manxbuggy1 and RMM used. Yes, we passed them around and compared the results because all of our light boxes were made by the same 2 guys. Richard even tested two different kinds of light meters.”
And yes Funtastic, that has always been my problem with the small calibration lights. When my box was built some 5 years ago the brothers R tested it with some 25 known brand ANSI rated lights, big ones small ones powerful ones and not so much. The averaging of these 25 lights gave me the multiplier I used. Then other people started making lesser boxes and tested with puny outputs and everybody signed up and declared my box numbers off by ludicrous margins. I finally just gave up. For the greater good, right or wrong, my box is now diffused to read actual lumens on the meter according to the Maukka calibration lights everbody else swears by. So the box is “sworn in” on a 290.8 lumen little tube light and I am supposed to assume my 4” diameter 17 emitter 23,300 lumen Ham’r is being given a fair shake. (this about 3000 lumens below what the original light box read)
If I ever find someone able to measure Ham’r in a true blue sphere I will certainly give it a go.
For whatever reason, Jason has been the biggest voice against my original light box and even now, calibrated according to Maukka, I am doubted. It is what it is I suppose. There was a time when experience counted for something. Seems I am misunderstood. I do not post “trying to have the biggest numbers”, I mod with top components, sparing no effort, (and have spent over $10,000 in the process) to show the maximum capability of a light to the best of my ability, share it to show what I have found can be done so other modders have a reference point and the stock light a base value. Some have found ways to surpass my findings and some have not. Not important really, the goal has always been to show that a stock light can be better and give an idea how much. And to inspire sales so we, this forum, can enjoy budget lights at their best. I have struggled with physical issues for over 20 years and I mod as an escape, I am not here to be constantly challenged and shot down so, to put it simply, I will not be here much any more.
We also have to remember that Jason's L6 is sliced. My understanding is that slicing can knock off as much as 30% lumens, which would easily drop 8000 to 5600. As for the lumen tubes, there are so many variables involved that I'm not sure how we can ever know whose tubes are measuring accurately. I appreciate the efforts to make your tube more consistent with other tubes Dale, whether that's more accurate or not.
I was under the impression you sent your Manx Buggy tube to Toykeeper and built yourself a newer, bigger diameter one. I don’t really know what’s going on with your lumen tubes lately, plus it’s hard for me to remember any changes you’ve recently done.
The only issues I had with the Manx Buggy tube is that it wasn’t diffused so thrower lights would read higher than floody lights. Secondly was that the calibration ws based on an average of several lights factory ratings. Those 2 things go against the basic principles of an integrating sphere which is to diffuse and integrate all the light together and then measure that light level with accuracy.
It would help me to understand if I knew more about your setup. Are you still using the Manx Buggy 3.5” tube but with 1, 2 or 3 added diffuser panels? Do you set the light on a glass shelf? Do you have some type of setup to put around the edge of the light to keep it from spilling out around the edges? Does the sensor mount on a flat wall at the end of the tube or in a necked down piece to capture more light? If your using a 6” to 4” adapter, does it taper down smoothly or does it bounce a lot of light directly back into the reflector? What effect does this have on the readings? When using the calibration light with the adapter, is the light shining down the middle or does it shine down the edge of the opening so some of the beam hits the reducer and bounces the light back towards the reflector.
So you see, we are not using the same design lunen tubes so there could be differences in the response curve or differences depending of the beam shape, etc…
The Texas_Ace Lumen Tube may not be perfect, but it’s consistent. That’s one of the key design points. If it’s inaccurate, it’s inaccurate for everyone so there is still consistency. This is why a I tell people to not take lumens so seriously. Homemade integrating spheres are great for doing mods and measuring if you got an improvement or not. They are also great for comparing different lights in a person’s collection.
Don’t be bitter, we are all just trying to understand things better. How can your 70.2 light read so many thousands of lumens higher when the amperage is so close (19A to 21A)? This really has me scratching my head. I wish our numbers were closer together.
I’ve been thinking about making a beach ball sized (1 meter) integrating sphere with a barium sulfate coating and a higher end lux meter, but it’s still really expensive and a lot of work. I don’t know if I care enough to built it. Flashlights are cool, but I’m not a Flashaholic or anything. I use them for work, not collecting.
You can’t go by that. That was written before TA had any calibrated source for his Lumen Tube and it was reading about 30–40 too high. I can’t remember the exact number.
You also have to factor in that he’s measuring a raw led with no reflector or lens. If you put that same led in a flashlight, the output goes down based on how efficient the reflector and lens is.
Sorry for the newbie question, but should I leave unprotected cells in my lights when they are not in use? Is there a safety concern? Again, apologies for the naive question.
It depends on the specific light. Some lights have very low parasitic drain and some don’t. If you aren’t going to be using a light for at least a few days then it’s best to mechanically lock it out. The SP70 has the tail switch to cut power. Some lights with anodized threads allow you to turn the tail cap half a turn to cut power. Lights with raw threads might require taking the battery out.
Some lights may take a couple of years to drain the batteries while other lights may only take a couple of weeks.
I lock out most of my lights mechanically. The ones I don’t are used pretty often and have very low drain. They also use protected cells.
All my lights using unprotected cells get locked out.
