I am stupid so can you help? Lux to lumen conversion.

[lostplanet]

as title, friend is looking at a torch that claims to be 6000 LX.

what is 6000 Lux in Lumens?

torch in question,

http://www.wilko.com/jml-products/j...werful-and-bright-led-flashlight/invt/0464470

but i have seen this:

https://www.amazon.co.uk/Flashlight-Rechargeable-TFCFL-Flashlights-Waterproof/dp/B01K9JWTX2

I have a P7R led lenser that is 1000 lumens and that is mighty bright for me.

 

[Mesquite]

Here's a lux to lumens calculator.

 

[lostplanet]

yes i did see that but cant work out how to use it.

 

[Mesquite]

yes i did see that but cant work out how to use it.

From what I can tell is you enter a figure for the lux and for the area that your light source will illuminate.

Once you have that it works out the lumens for you.

 

[Jared]

Can't really convert them, without knowing more details.
Lumens is total light output, lux is how intense the centre is, effectively how far it throws, double the lux, light reaches 50% further.

 

[Jared]

PS: If want a pretty good value light, Atactical/WowTac A1S available in the UK...

https://www.amazon.co.uk/Flashlight...F8&qid=1511279170&sr=8-2&keywords=wowtac&th=1

 

[Nice65]

as title, friend is looking at a torch that claims to be 6000 LX.

what is 6000 Lux in Lumens?

torch in question,

http://www.wilko.com/jml-products/j...werful-and-bright-led-flashlight/invt/0464470

but i have seen this:

https://www.amazon.co.uk/Flashlight-Rechargeable-TFCFL-Flashlights-Waterproof/dp/B01K9JWTX2

I have a P7R led lenser that is 1000 lumens and that is mighty bright for me.

The multi led light you link to is probably not what it seems. It's very easy for a manufacturer to get 10 x 1000 lumen leds together and call it a 10000 lumen torch etc. Those multi led torches froduce a floody spread of light that is only claimed to reach 100m.

The exact same torch is listed here at 20,000 lumens. It's all tosh. The torches are mass produced in China then given a brand logo and sold by companies who claim anything they want. I'd be suspicious of the JML that your mates looking at. There are very similar looking torches on the Chinese websites.

https://www.bingabinga.co.uk/20000-...-led-flashlights-torch-for-18650-battery.html

Ignore lux, particularly with a zoomable torch that has various ares of illumination, it's misleading.

 

[Fadcode]

Lux and lumens are two entirely different things, so therefore a conversion from one to the other cannot be made....therefore to give you some idea

If we take a flux of 1,000 lumens, in an area of one square metre, it illuminates that square meter with an illuminance of 1,000 lux. The same 1,000 lumens, over ten square meters, produces an illuminance of only 100 lux.

 

[Paul_B]

Personally I think the lux lumens thing is about confusing the customer. If you've got an idea of lumens through use (most bike lights in the UK are sold with lumens you'll know what is bright enough for you with that figure. Switch it to lux you have no idea. A brand could really sell you a dude and you'd not know.

Put simply lighting manufacturers need to standardize. Lumens is more commonly used I think. Use of lux could be construed as trying to confuse potential customers.

Having said that use of lumens needs to be controlled. None of this led adding up of lumens nonsense. It's just all confusing to many. One scale that indicates torch x is brighter or dimmer than torch y. Simple enough right?

 

[Jared]

I hope the more egregious claims would fall fowl of advertising standards.

The LED adding up of lumens does work to a point. But given a modern LED typically needs around 3 amps to get 1000 lumen out of it... you'd need high quality high drain batteries, and then the amount of heat generated is going to be a problem.

For example, the Emisars, the D4 has 4 LEDs and will get around 4000 lumen with a good 18650 capable of delivering 15 amps, but gets hot quickly.
Whereas the D1 only has a single LED but bigger optics will out throw the D4 out to 400m-ish, and the D1s out to 700m-ish.
ToyKeeper has some pretty in depth reviews on budgetlightforum.

http://intl-outdoor.com/led-flashlights-c-1.html

 

[lostplanet]

Thats something i was considering, with all this so called power, how long would a torch even last. My P7R is 1000 lumens for 2 hours max according to the manufacturer.
https://www.ledlenserusa.com/p7r-495.html

something with 20000 lumens is going to last 20/30 minutes?

Also my torch is great when out and about, but to use it on full power in close proximity like changing a tyre or working under a bonnet, it would be(is) ridiculously bright and painful to work near. I am glad i can choose the output but even then with the lowest setting its still very bright close up.

 

[lostplanet]

Personally I think the lux lumens thing is about confusing the customer. If you've got an idea of lumens through use (most bike lights in the UK are sold with lumens you'll know what is bright enough for you with that figure. Switch it to lux you have no idea. A brand could really sell you a dude and you'd not know.

Put simply lighting manufacturers need to standardize. Lumens is more commonly used I think. Use of lux could be construed as trying to confuse potential customers.

Having said that use of lumens needs to be controlled. None of this led adding up of lumens nonsense. It's just all confusing to many. One scale that indicates torch x is brighter or dimmer than torch y. Simple enough right?

I agree there should be a standard, look at the the mess around sound output, RMS, Peak Power, Max power in watts, and that's been going on for decades.

 

[lostplanet]

heinnie's newsletter came back with this:

https://www.heinnie.com/imalent-dx8...147096209&mc_cid=c4104b18a7&mc_eid=8bd9d7d1a9

and a quick google lands these:

https://www.google.co.uk/search?q=I....69i57j69i60j69i61l2&sourceid=chrome&ie=UTF-8

MMM.... is that really necessary unless you are an aircraft or ship?

review from heinnie

Decent with downsidesReview by Alex
Rating

The torch is well made as befits the price but I have actually returned the item chiefly on the weight distribution and ergonomics. The battery pack is large as you'd expect to achieve any decent amount of run time and thus the diameter of the grip is large. I have large hands and they just fit the grip but over extended use, I could see how this would cause fatigue. The torch weighs 1.2kg but feels heavier due to what I would consider poor balance. It doesn't sit comfortably in the hand and with the diameter of the grip, makes for poor handling.

While not a criticism, the beam pattern is not ideal, it has a very wide throw where I would have preferred to translate that into a narrow beam, only 5-10 degrees say but with the power output, that would give the beam much greater reach.[Quote\]

 

[Jared]

Yeah, think that the current brightest light in raw lumens.

The BLF GT is the farthest thrower, at over ~2200 meters (1.3 miles) (~1800 lumens)

 

[Broch]

Sorry guys, but these are the correct ways of describing light output. I agree they are used in exaggerated ways and can be confusing but it's the same concept as describing force and pressure - a point measurement and a measurement of spread over area. I just look at it as the lumens representing the available 'light output' which you can spread over different areas by using lenses (with some loss).