lumens

[rikgrimsby]

what would a 4000 lumens flash light be in terms of watts ?

 

[rangedunits]

id say 50w

 

[rikgrimsby]

cool. theres a hid flash light on ebay 4000 lumens for £150
not bad i thought

 

[ossumguywill]

Lumens and watts are not comparable units. Lumens are units of integrated relative illuminance.

 

[lightake]

4000 lm?
Didn't see it before , i only see the 2200lumens flashight ,it it super bright .i didn't like a flashlight that was so bright !

If £ 150 can buy 4000 lumens flashlight ,itis not very bad !

 

[rikgrimsby]

4000 lm?
Didn't see it before , i only see the 2200lumens flashight ,it it super bright .i didn't like a flashlight that was so bright !

If £ 150 can buy 4000 lumens flashlight ,itis not very bad !

its on the uk ebay from a uk seller. am just waiting till payday then ill get it

 

[jedirock]

4000 lm?
Didn't see it before , i only see the 2200lumens flashight ,it it super bright .i didn't like a flashlight that was so bright !

If £ 150 can buy 4000 lumens flashlight ,itis not very bad !

Sounds like you're thinking of the Olight SR90. That's an LED flashlight, where 2200 lumens is very bright. He's talking about a HID bulb, which is a different technology altogether. Gas-discharge lamp - Wikipedia, the free encyclopedia

 

[Toke]

Luminous efficacy - Wikipedia, the free encyclopedia

Here is a list of assorted light sources and their range of lumen/watt.
If you look at datasheet for e.g. sst-90 you will find that they are quite proud to achieve 100LM pr watt, and that it only happens at some light levels.

The guess of 50W above is not far off.
The SST-90 can give off 2250 LM at app. 30W, so 50-60W for 4000LM appear to be state of the art for LED's. In practicality 4000LM would likely be done with 3 SST-90 running below max output, but at higher efficiency.

 

[Firsh]

The watt number depends on the efficiency of the bulb. I learnt this when I was going to buy a led bulb and compared the lum value to the regular light bulbs.. I'm curious, what would be the lum number for a laser pointer which is like 100mW?

 

[Toke]

The watt number depends on the efficiency of the bulb. I learnt this when I was going to buy a led bulb and compared the lum value to the regular light bulbs.. I'm curious, what would be the lum number for a laser pointer which is like 100mW?

App. 60LM for a 532nm.

Read post #4 and my link above.

 

[emboli]

I can imaging that flashlight burning my hand within 5min of use

 

[Vextor]

How can I check if a flashlight has the advertised lumen power?

 

[BShanahan14rulz]

Integrating sphere.

 

[Vextor]

Integrating sphere.

Isn't there any other way? That is definitely a way I can't (pratical/cost). I thought of something pratical, low cost.