Huge List of Ceiling Bounce Readings (Every mode from every flashlight in my collection!!!)

thanks for this. alot of good data here, and boy do you have a lot of lights.

I love stuff like this. For sure do the conversion to lumens. I was doing x15 in my head but I think Scaru got it right :slight_smile:

Some surprises in there to me, will enjoy looking at the listing a second time when you post lumens. Nice collection of lights too!

Next comment - were you surprised by any of the results, thinking one was outputting a whole lot more, etc?

Nice list! Thanks for putting in the time to do this.

Thanks for doing all that. A really nice reference point for comparisons.

:slight_smile:


I saw a lot of beams yesterday but none of them really made me question the readings. I think the CW readings might be a little higher than they should be and the NW ones a little lower than what they should be. However, it might just be my eyes playing tricks on me. I think the readings are fairly close. If they are off, it isn't by very much.


My surprises:
B40S= Holy cow it can put out a lot of light

TN30 XM-L2= What a versatile light! 3180 lumens all the way down to moonlight. An amazing light that will not be leaving my collection for a very long time.

DRY= Even though feature wise I don't like this flashlight it sure is bright. It placed 3rd amongst some really bright lights! I just hate having strobe between Hi and Turbo.

Sky Ray King= Not sure why there is such a huge variation between lights here. They are all XM-L T6 (my signature is wrong, the two from CNQualitygoods are definitely both NW T6). The Lightmalls ones has had about 2 sets of batteries through it so I'm not sure if that is affecting it's performance or maybe it's not an authentic one. The cnquality ones also have quite a spread too. The six-month old (120lux) one has had one set of batteries thought it and the (140lux) one is new. Once again maybe the emitters are getting too hot?


BTU Shocker= A great mix of flood and throw. I just wish it was 4x18650 and had a sideswitch.

TN31 XM-L2= Another ridiculous light, the throw is amazing and I can never get enough of moonlight mode.

HD2010= This light is a diamond in the rough for sure. It out-throws both of my STL-V6s. The last one I bought from the same place (easylightbuy) isn't nearly the same light. So when you hear me talk about a "good" HD2010, this is what I mean.

ZY-T08= At only 670 lumens this light has some serious potential. It would be a great light if it is bumped up into the 900+ lumen range.


UltraFire C8= This is another diamond in the rough. It performs like a U2 or U3 but I bought it over a year ago so I am pretty sure it is a legit T6.

UltraFire 980L= It doesn't seem to be performing as well as it should. I really think it is an authentic one because I bought it a while ago after reading Foy's review and from Manafont. I think my batteries might be limiting this light?


SolarForce L2P w/ intl-outdoor NW= I think this light should be at about 700lumens. This is really the one reading that stands out to me as being low. It is a very nice drop-in with an awesome tint and 2.5amps is just about right for a P60 in my opinion.

SureFire G2= Hah, can you believe this light started it all?!? I used to think this light was bright...


HD2011= I really like this light for an EDC. On high (more like turbo) I wrap my hand around the head. I typically use it on medium though because 400 lumens is usually plenty.

UltraFire G10= This light is a monster on a 14500 battery. I'm not sure how long it will last but man is it bright.

UltraFire U20S- This is my EDC light 75% of the time. There is very little heat sag; it maintained its lux reading way longer than the rest of the AA lights.


Ti2= This might become my new EDC because it is so small and extremely bright for it's size.

Ti= I'm not sure why there is a variation here between lights. They are both brand new.


SK98= This light has literally no heat transfer so it probably wouldn't last long if you plan to use it for long periods. However, it is my favorite "wall of light" flashlight that I own. I mean the wide, bright beam is jaw dropping.

Tank TK736= This is a great light with amazing build quality. I just wish it was brighter. I still think if someone is looking for a nice zoomie they should buy one.

Sipik Clones= Everyone needs to give these to all of their family members and have one in every vehicle. They are great lights and for $6 you just can't beat them.

Thanks for catching those two errors. My calculator and keyboard was getting a workout so I knew I would probably mess something up. Glad it was two quick fixes.

Did you say my test is impossible?

Ceiling bounce readings are simply (big) lightbox readings. Please see:

Ya I don't take my readings as being 100% of what they really are but they seem like they are fairly close. I am mostly using this data for comparing my lights against one another.


I still don't undertand what you mean by "This kind of accuracy with such varied lights and emitters is impossible with ceiling bounce readings taken with a $29 lux meter."

What is "this kind of accuracy"? My data is linear because I multiplied all points by 16.74.

You can’t just take readings and multiply by a constant. Real life is a lot “messier.” Did you read Selfbuilt’s post I gave you the link to and look at his plots? If you want to estimate lumens with a lux meter and a lightbox, take a series of readings versus their reported IS lumens and make a regression formula from them with lumens being the dependent variable, then plug any new lux readings into THAT to estimate lumens, assuming the new readings were taken under the exact same conditions as the readings you developed the regression formula from.

Ok, ya I see what you mean.

Ooooh, to complicated. Just pull a random number out of you ass and mulltiply it by 5 like all the Chinese sellers do. :wink:

:smiley:

Sounds complicated but actually it’s just a few clicks in excel. 8)


I really familiar with doing regression lines in Excel but that is when I have two numbers for each data point.

How can you do a regression line with only one number for each data point?

Think of the room you’re doing your ceiling bounce readings in as a big lightbox because in effect it is, and I’ll call it that to keep things simple. A lux is one lumen per square meter but what we really want to know is, how do lux as measured in your particular lightbox translate into lumens? That’s what the regression formula is for. We need two columns of data to come up with it: 1) lux as measured in the lightbox (your ceiling bounce readings), and 2) actual lumens. Ideally, we’d get the latter from calibrated integrating sphere readings of each light but not everyone has a calibrated integrating sphere handy and if we did we wouldn’t need to do ceiling bounce readings, so we’ll use manufacturer reported lumens that we believe are credible as a proxy. What the regression formula does is quantify the relationship between lux, as measured by your readings, and lumens which can then be applied to other lights. In other words, you develop the formula with maybe ten or so lights (using your lux readings versus manufacturer reported lumens) and then use it to estimate the lumens of other, different lights by plugging the ceiling bounce readings of those lights into the regression formula.

Ya see that is the problem. (Finding the second column of actual lumens)

We have to remove all ****fire type of lights because they all have extremely exaggerated lumens. That leaves us with Thrunite basically. Who knows maybe they are exaggerated as well.

I'm not sure where you can find accurate lumen numbers for these lights.

Appreciate your detailed answers to my questions. Looking to put a good size flood on my shelf soon and your information & comments were helpful.

The problem is that I only have a few lights that I feel confident in the manufacturer lumens. (from ThruNite so six flashlights)

I also think your data would be much closer to 1 if you used an exponential regression line. A polynomial one would get you ever closer to 1 but it would be unrealistic.

I've thought about doing what you are doing before but I never had lights from a manufacturer that didn't exaggerate the lumens.

The reason I mentioned exponential is because your numbers don't look linear. They suggest an upward curve. I don't see why you say it is terrible because I bet it gives you a better R^2 value. I agree a linear line is ideal because that "should be" the relationship between lux and lumens.

Ya I know polynomial isn't realistic that's why I said it would be "unrealistic". You can make almost any set of data R^2=1 with a polynomial regression line which isn't a good thing when there is a limited amount of data points.

I don't claim to know everything about this. I am just questioning why you trust manufacturer lumens. I know we have to start somewhere but why bash me for giving approximate lumens?

I know you are trying to help and your light box and lux reading knowledge greatly surpasses mine. But I'm not exactly "just starting out"... not sure how you gathered that? I live and breathe flashlights and run my own flashlight business. (currently expanding online) I am currently seeking my BA in Marketing because I would like to become Product Manger/Sales Manager/etc. for a flashlight company one day.

The reason I posted about reading my lux meter is because the numbers were so off that I assumed I must have been reading it wrong. I was reading it right. My numbers were off because it isn't exactly spelled out that everyone did there lux readings at more than 1m and then converted back. I think anyone doing lux readings the first time would assume the same thing.

I just love flashlights and am proud to have BLF to talk about these amazing gems.

This week I will try to get a regression line figured out that I feel confident and will update my estimated lumens readings. I think they are close but I would like to get them closer. Thanks luvlites for sparking my interest in getting my numbers closer perfect.