Lumens / Kerskrag
Posted: Thu Dec 13, 2012 7:11 pm
Ek weet maar altyd van flitse wat 1,000,000 of 2,000,000 kerslig het...hoe vergelyk?, of hoe convert? jy kerskrag no lumens.
Cheers
Cheers
Page 1 of 1
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 7:27 pm
? Geen idee nie! Sal graag ook wil weet!
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 7:43 pm
Cobb
Dit is volgens my n ingewikkelde som nie goed met wiskunde nie daar is twee standaarde wat hulle gebruik. Maar gaan kyk op candle power forum dit is die naam daar vertel hulle jou van al hierdie goed. Hoop dit help.
Beretta
Dit is volgens my n ingewikkelde som nie goed met wiskunde nie daar is twee standaarde wat hulle gebruik. Maar gaan kyk op candle power forum dit is die naam daar vertel hulle jou van al hierdie goed. Hoop dit help.
Beretta
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 7:58 pm
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 8:24 pm
Dis ingewikkeld kerslig per vierkante meter of voet of duim daar baie verskillende maatstawe maar kerlig per viekante meter is gelyk aan lumen per steradian square meter
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 8:30 pm
Remmington....dis presies my pyn ook....ek het 'n online conversion website maar als soek nog m2 en ft2 by...remington wrote: Dis ingewikkeld kerslig per vierkante meter of voet of duim daar baie verskillende maatstawe maar kerlig per viekante meter is gelyk aan lumen per steradian square meter
Dankie vir almal se terugskrywe
Cheers
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 8:34 pm
Die lig moet op n sekere plek gemeet word een persoon se sy manier is beter as die ander een sin maar soos ek gehoor het gaan daar nou standaard wees vir al die lgte
Beretta
Beretta
Re: Lumens / Kerskrag
Posted: Thu Dec 13, 2012 8:54 pm
Dit is nou wat die kerskrag forum manne ons leer.
There is no easy or direct comparison between Lumen and Candlepower ratings.
Lumens are a measure of the total amount of light emitted in all directions, and while not entirely appropriate when applied to directional light sources like flashlights, it still can be used to measure all the light poured out the end of your torch, regardless of what direction it`s going in.
Candlepower or Candela is a peak spot measure- the intensity of the very brightest point of light within the focussed beam, usually the very center. It does relate with Lumens, to the half angle of the beam- in other words, the angle from the centre at which the brightness is exactly half of the peak value at the centre. For an identical intensity light source (ie, lumen value is the same) the narrower the beam the higher the Candlepower rating. But the dispersion of the beam plays a big role. It depends largely on the width of the hotspot, what portion of the light goes into the main beam, and what portion spills off to the side.
Unless you know the precise dispersion of the individual beams, with an accurate 2 dimentional plot of intensity (or a simple 1-dimention graph if the dispertion is perfectly circular and not lopsided or oval), and then apply advanced mathematics that would make most highschool students heads spin, you cannot convert between the two. Can`t be done, sorry.
Regrettably there is not a simple home-friendly way to measure lumen outputs. A simple photographic Lux meter can be used to give you candela (candlepower) readings but Lumens require advanced methods. You need lots of space, lots of money and lots of Barium Sulphate paint in order to do it. Hence why most manufacturers just use candlepower. Additionally (and maybe more influencially), candlepower figures are often high and look great on fancy packaging and web sites- that thing about narrow beams again. Many Pelican lights and all Maglites for example, are rated quite highly as far as cp goes, but the overall light output is low compared to some, just the fact that they can focus pretty narrowly. A narrow beam is not always a useful beam so candlepower ratings cannot be soley relied upon. Similarly Lumen ratings cannot be soley relied upon either. A high-lumen beam could be so wide and dispersed that it does not throw more than a few feet, or a low lumen beam could be so narrow that it shines a very long way.
It`s all down to what you`re looking for in a lignt and until flashlight manufacturers get their act together and embrace a universal, standardised and informative rating method they will all use, the only real way to tell if one torch is better for you than another is to try it out yourself. Hence the official CPF motto "Get them both
". We reviewers try our best but however detailed we try to be in our writeups, you still cannot beat seeing the thing for yourself
There is no easy or direct comparison between Lumen and Candlepower ratings.
Lumens are a measure of the total amount of light emitted in all directions, and while not entirely appropriate when applied to directional light sources like flashlights, it still can be used to measure all the light poured out the end of your torch, regardless of what direction it`s going in.
Candlepower or Candela is a peak spot measure- the intensity of the very brightest point of light within the focussed beam, usually the very center. It does relate with Lumens, to the half angle of the beam- in other words, the angle from the centre at which the brightness is exactly half of the peak value at the centre. For an identical intensity light source (ie, lumen value is the same) the narrower the beam the higher the Candlepower rating. But the dispersion of the beam plays a big role. It depends largely on the width of the hotspot, what portion of the light goes into the main beam, and what portion spills off to the side.
Unless you know the precise dispersion of the individual beams, with an accurate 2 dimentional plot of intensity (or a simple 1-dimention graph if the dispertion is perfectly circular and not lopsided or oval), and then apply advanced mathematics that would make most highschool students heads spin, you cannot convert between the two. Can`t be done, sorry.
Regrettably there is not a simple home-friendly way to measure lumen outputs. A simple photographic Lux meter can be used to give you candela (candlepower) readings but Lumens require advanced methods. You need lots of space, lots of money and lots of Barium Sulphate paint in order to do it. Hence why most manufacturers just use candlepower. Additionally (and maybe more influencially), candlepower figures are often high and look great on fancy packaging and web sites- that thing about narrow beams again. Many Pelican lights and all Maglites for example, are rated quite highly as far as cp goes, but the overall light output is low compared to some, just the fact that they can focus pretty narrowly. A narrow beam is not always a useful beam so candlepower ratings cannot be soley relied upon. Similarly Lumen ratings cannot be soley relied upon either. A high-lumen beam could be so wide and dispersed that it does not throw more than a few feet, or a low lumen beam could be so narrow that it shines a very long way.
It`s all down to what you`re looking for in a lignt and until flashlight manufacturers get their act together and embrace a universal, standardised and informative rating method they will all use, the only real way to tell if one torch is better for you than another is to try it out yourself. Hence the official CPF motto "Get them both
". We reviewers try our best but however detailed we try to be in our writeups, you still cannot beat seeing the thing for yourselfRe: Lumens / Kerskrag
Posted: Sat Dec 15, 2012 12:46 pm
Cobus,
Inligting wat ek het is dat Kerskrag word in n rigting gemeet soos bv n flits en Lumens in n vertrek / area se beligting. Indien die beligting van n area compress word en in bv n rigting gemeet in lumens kan die standaard gebruik word van 1 kerskrag is gelykstaande aan 12.57 lumens.Dan moet ons ook onthou die reflector compress die strale om n beam te gooi en die lig rondom die beam word in lumens gemeet en dus die lae lumens telling met n lekker straal.
Minimun toelaatbare lig vir ons hier op konstruksie vir nagwerk is 100 lumens en dis darem wragties lekker lig.(Area beligting)
Sal bietjie n flits vat en in die meter skyn en kyk watse lesing ek kry en laat weet.
Hoop dis verstaanbaar.
Groetnis
Inligting wat ek het is dat Kerskrag word in n rigting gemeet soos bv n flits en Lumens in n vertrek / area se beligting. Indien die beligting van n area compress word en in bv n rigting gemeet in lumens kan die standaard gebruik word van 1 kerskrag is gelykstaande aan 12.57 lumens.Dan moet ons ook onthou die reflector compress die strale om n beam te gooi en die lig rondom die beam word in lumens gemeet en dus die lae lumens telling met n lekker straal.
Minimun toelaatbare lig vir ons hier op konstruksie vir nagwerk is 100 lumens en dis darem wragties lekker lig.(Area beligting)
Sal bietjie n flits vat en in die meter skyn en kyk watse lesing ek kry en laat weet.
Hoop dis verstaanbaar.
Groetnis