Light wiring question

[bogan]

Agreed. I tend to use lumen.

Yup, lumens for the source, lux for the lit surface. Incidentally, you want to ensure the lux is balanced out a bit, rather than having one very bright spot, which reduces you ability to see in the less lit areas of vision.

[Coldrider]

Yup, lumens for the source, lux for the lit surface. Incidentally, you want to ensure the lux is balanced out a bit, rather than having one very bright spot, which reduces you ability to see in the less lit areas of vision.

Illuminance is lux and lumens.

lumen is one foot candle on one square foot of area. lux is the metric equivalent. radiance is energy released at the light source.

[bogan]

Illuminance is lux and lumens.

lumen is one foot candle on one square foot of area. lux is the metric equivalent. radiance is energy released at the light source.

You sure? Somebody needs to re-write the wiki page then, and a bunch of LED data sheets...

[Coldrider]

You sure? Somebody needs to re-write the wiki page then, and a bunch of LED data sheets...

One lux is a lumen per square meter, a lumen is one footcandle on one square foot of area. The measurement is different but they are both measuring light falling on a surface distant from the source. The lux is metricated. Lumens are not the source.

Unashamedly stolen from wiki
The unit is defined as the amount of illumination the inside surface of a 1-foot radius sphere would be receiving if there were a uniform point source of one candela in the exact center of the sphere. Alternatively, it can be defined as the illuminance on a 1-square foot surface of which there is a uniformly distributed flux of one lumen. This can be thought of as the amount of light that actually falls on a given surface. The foot-candle is equal to one lumen per square foot.

Illuminance is a measure of how much luminous flux is spread over a given area. One can think of luminous flux (measured in lumens) as a measure of the total "amount" of visible light present, and the illuminance as a measure of the intensity of illumination on a surface. A given amount of light will illuminate a surface more dimly if it is spread over a larger area, so illuminance is inversely proportional to area.

One lux is equal to one lumen per square metre:

[ducatilover]

6000k bulbs. .

There's the issue, way to high a colour temp for my liking too. Sad thing is you can only really learn this by buying expensive bulbs and having a the first time you ride.
Linky for help with colour temps too http://www.automotiveforums.com/t177...ht_output.html

[Coldrider]

Try this thread http://www.kiwibiker.co.nz/forums/sh...highlight=spot

[bogan]

One lux is a lumen per square meter, a lumen is one footcandle on one square foot of area. The measurement is different but they are both measuring light falling on a surface distant from the source. The lux is metricated. Lumens are not the source.

Unashamedly stolen from wiki
The unit is defined as the amount of illumination the inside surface of a 1-foot radius sphere would be receiving if there were a uniform point source of one candela in the exact center of the sphere. Alternatively, it can be defined as the illuminance on a 1-square foot surface of which there is a uniformly distributed flux of one lumen. This can be thought of as the amount of light that actually falls on a given surface. The foot-candle is equal to one lumen per square foot.

Illuminance is a measure of how much luminous flux is spread over a given area. One can think of luminous flux (measured in lumens) as a measure of the total "amount" of visible light present, and the illuminance as a measure of the intensity of illumination on a surface. A given amount of light will illuminate a surface more dimly if it is spread over a larger area, so illuminance is inversely proportional to area.

One lux is equal to one lumen per square metre:

Give it a closer read (esp the bold bit), the amount of illumination on the inside of a sphere, is going to be the total light output from the source, where else is it going to go? Also, lux is defined as lumens per square meter, if lumens were already a per-area unit, this would not make sense.

[Coldrider]

Yup, lumens for the source, lux for the lit surface.

Have another read, lumens is not for the source, a CANDELA is the source.
A square metre of surface, one metre from the 1 candela light source, 1 lumen falls on this surface. incidently, the lux measured on a surface 1 metre from the 1 candela source is also 1 Lux. So at this point (only) both 1 lumen and 1 lux are the same. So how can the lumen be the source?

[bogan]

Have another read, lumens is not for the source, a CANDELA is the source.
A square metre of surface, one metre from the 1 candela light source, 1 lumen falls on this surface. incidently, the lux measured on a surface 1 metre from the 1 candela source is also 1 Lux. So at this point (only) both 1 lumen and 1 lux are the same. So how can the lumen be the source?

Thats is how they calibrate/normalise between the different units. It makes it easy to judge how bright a surface (lux) will be from a bulb of specified brightness (lumens). Candela is not used for total output intensity either, the candela unit is the power emitted by a light source in a particular direction.

Candela: intensity of a beam output form a light source, think single dimensional measurement (though in practice a small area will always be used.
Lumen: Luminous power of all beams output from a light source, normalised so 1 lumen is output from an omnidirectional light source of one candela
Lux: Light hitting a surface, given by lumens per square meter.

To bring this back to more practical discussion. My HID kit (legal) outputs 3100-3400lumens with a color temp of 4300k, a 50W halogen outputs 800-900lumens at around 3000k. A tail light is around 200lumens.

[Coldrider]

My practical experience is replacing my orignal headlamp oem bulb with a repco artic blue, same watts, but throws a beam such that I can see as much with my tinted visor at night, as with the original with a clear visor. I think it is more luminous because it throws a beam with less holes and scatter in it.

The bulb also relies heavily on the light reflector design, which is alot harder to alter, if at all. Some models will no doubt be very affected by this.

[FROSTY:Me]

hey spokes-not taking the piss here-Try wearing dark sunnies about 15 minutes before you ride and as you are getting on the bike. It tricks your eyes into working better

[nzspokes]

hey spokes-not taking the piss here-Try wearing dark sunnies about 15 minutes before you ride and as you are getting on the bike. It tricks your eyes into working better

Ive tried that for MTB riding. Worked ok so you have night eyes from the start. But I adjusted my low beam so will see how that works out Wednesday night.