With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?

"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure
the brightness of a light? Something I can use to compare bulbs in my
home, auto headlights, flashlights, etc?


A light meter.

"John Grabowski" wrote in message
...

"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure
the brightness of a light? Something I can use to compare bulbs in my
home, auto headlights, flashlights, etc?


A light meter.

Hrm... so a heavy meter won't work? How about a kilometer?

: )

In article XHP%j.177183$Cj7.174287@pd7urf2no, "Calab"
wrote:

With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?

You might start with this short primer on lighting terminology. Then
decide what it is you really want to measure.

http://www.energybooks.com/pdf/D1150.pdf

Calab wrote:
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?


It's been close to fifty years since I've made measurements of this sort
but I can recall building and using an 'integrating sphere.' The
purpose is to collect and measure all of the radiation (in this case
visible light) that the lamp emits. The lamp is placed within the
reflecting sphere and this results in uniform brightness everywhere on
the surface of the sphere. You can measure the area of the detector and
the sphere and by using the ratio of these areas and the energy measured
by the detector you can calculate the total energy. Many factors will
influence the accuracy of the absolute measurement but for comparative
measurements it's pretty straight forward.

To get a pretty good comparison I'd consider painting the inside of a
large six sided square cardboard box white, placing the lamp into the
box, and then measuring the brightness anywhere on the interior of the
box. Be careful to not point the light meter directly at the lamp. If
you place each lamp and the light meter in the same place for all
measurements the comparative info should be pretty good.

http://www.piketech.com/technical/ap...tro&Theory.pdf

if it's some odd ball bulb you can use an odometer.

s


"Calab" wrote in message
news:GgS%j.305849$pM4.128336@pd7urf1no...

Hrm... so a heavy meter won't work? How about a kilometer?

: )

In article ,
wrote:

On Fri, 30 May 2008 06:19:31 -0400, "John Grabowski"
wrote:


"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure
the brightness of a light? Something I can use to compare bulbs in my
home, auto headlights, flashlights, etc?


A light meter.

Correct, and for the OP, they are sold at camera stores.
Profesional photographers use them all the time. I'm sure you can
find them online too.

The OP didn't mention photography, so I doubt that he wants to measure
footcandles. He may mean lumens, or candlepower, or luminance. The pdf
link I posted is a good primer.

"Calab" wrote:

With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure
the brightness of a light? Something I can use to compare bulbs in my
home, auto headlights, flashlights, etc?

You might compare the outputs of bulbs with similar light patterns with
Robert Wilhelm Bunsen's 1844 "grease spot photometer." Put a 3x5 card with
a grease spot between them and measure the distance to each bulb when
the spot disappears (when it is equally-illuminated from both sides of
the card.) The outputs are then proportional to the inverse square of
the distances. For instance, if the card is 19" from the CF and 21" from
the incandescent bulb, the CF's output is 100(19/21)^2 = 82% of the bulb's.
You might screw both lamps into 2-prong sockets plugged into Kill-A-Watt
meters to measure the power...

Bunsen blew himself up with explosive gases on a regular basis.
He also invented the Bunsen burner, after his lab tech Desaga
invented it, after Michael Faraday invented it :-)

Nick

Calab wrote:
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?

If you stick with bulbs in your home, incandescents or CFLs, all you
need to do is read the packaging.

As Joseph pointed out, you need different measuring techniques and tools
for different types of bulbs.

The Mouser Electronics Catalog lists quite a few different bulbs and
often gives the amount of light they put out. Only problem is you will
have to be able to convert "End Foot Candles", "MCD", "M.S.C.P.",
"Luminous Intensity", "Lumens", and probably a few more types of light
measurement.

WWW.mouser.com

Search using key words "lamps incandescent", "lamps cfl", and "lamps led".

The Grainger catalog may have some info also.

Tony

Smitty Two wrote in
news
In article ,
wrote:

On Fri, 30 May 2008 06:19:31 -0400, "John Grabowski"
wrote:


"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I
was wondering... Is there a device that can be used to
objectively measure the brightness of a light? Something I can use
to compare bulbs in my home, auto headlights, flashlights, etc?


A light meter.

Correct, and for the OP, they are sold at camera stores.
Profesional photographers use them all the time. I'm sure you can
find them online too.

The OP didn't mention photography, so I doubt that he wants to measure
footcandles. He may mean lumens, or candlepower, or luminance. The pdf
link I posted is a good primer.


better light meters will convert measurements.

--
Jim Yanik
jyanik
at
kua.net

In article ,
Jim Yanik wrote:

Smitty Two wrote in
news
In article ,
wrote:

On Fri, 30 May 2008 06:19:31 -0400, "John Grabowski"
wrote:


"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I
was wondering... Is there a device that can be used to
objectively measure the brightness of a light? Something I can use
to compare bulbs in my home, auto headlights, flashlights, etc?


A light meter.

Correct, and for the OP, they are sold at camera stores.
Profesional photographers use them all the time. I'm sure you can
find them online too.

The OP didn't mention photography, so I doubt that he wants to measure
footcandles. He may mean lumens, or candlepower, or luminance. The pdf
link I posted is a good primer.


better light meters will convert measurements.

Apples and oranges, Jim. No conversion exists between the many ways to
measure light intensity, because they all mean different things.

"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure
the brightness of a light? Something I can use to compare bulbs in my
home, auto headlights, flashlights, etc?


There are meters that measure foot candles and they start around $75 and go
over $200. Keep in mind, the brightness of the bulb is only one factor in
proper lighting. What you generally want to measure is how much light is
falling on the object you are using or working with. A bright bulb in a
fixture with poor reflectivity is far worse than a less light bulb with good
even light. Not to mention light color temperature.

Bright bulbs can be harsh and tiring on the eyes while a diffused light can
work well for the same task. At work, I don't use any light in my office as
two windows give me all the light I want most of the time. Since about
early March, I've only turned the lights on maybe three times. Even then, I
prefer to use incandescent over fluorescent on the desk. In the shop, we
just installed fixtures with 6 T-8 lamps in them and they are very good
around machines.

Any camera which provides shutter information (shutter speed / f-stop) is a
useful measurement device. Not only can a specific combination of f-stop,
shutter speed, and ISO be directly translated to an objective and quantified
light value, but each stop difference can be used to measure relative
increase or decrease in brightness.

Smarty


"Tony Hwang" wrote in message
news:N740k.307332$pM4.192908@pd7urf1no...
Red Green wrote:

"Calab" wrote in news:GgS%j.305849$pM4.128336@pd7urf1no:


"John Grabowski" wrote in message
...

"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...

With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively
measure the brightness of a light? Something I can use to compare
bulbs in my home, auto headlights, flashlights, etc?


A light meter.

Hrm... so a heavy meter won't work? How about a kilometer?

: )




Barometer?\
Hi,
Unless you want to measure it like in the unit of Lumen, for just
comparison purpose a light sensing diode and resulting current measurement
possible. Stronger light produce more current.

With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?

Well, what I was looking for was something, with a 1" square (or
whatever) sensor, that I put at a specific distance from each light
source. All I want to know is how much visible light hits the sensor.

I don't need to know how well it lights a room, or the quality of the
light.

--
Fight Usenet Spam!!! - http://improve-usenet.org:80/

Want a great newsgroup reader that will filter out the flood of
newgroup spam?
Try MesNews - http://www.mesnews.net/gb/

If you want your posts to be seen, DON'T USE GOOGLE GROUPS!

On Sat, 31 May 2008 22:05:21 GMT, Calab wrote:

With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?

Well, what I was looking for was something, with a 1" square (or
whatever) sensor, that I put at a specific distance from each light
source. All I want to know is how much visible light hits the sensor.

I don't need to know how well it lights a room, or the quality of the
light.

Sounds like a lightmeter [light meter, luxmeter]. Measures lux- can
be had for $5 at garage sales/ebay - or probably $50 or so at a camera
store.

Jim

In article ,
Smitty Two wrote:
In article ,
wrote:

On Fri, 30 May 2008 06:19:31 -0400, "John Grabowski"
wrote:


"Calab" wrote in message
news:XHP%j.177183$Cj7.174287@pd7urf2no...
With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure
the brightness of a light? Something I can use to compare bulbs in my
home, auto headlights, flashlights, etc?


A light meter.

Correct, and for the OP, they are sold at camera stores.
Profesional photographers use them all the time. I'm sure you can
find them online too.

The OP didn't mention photography, so I doubt that he wants to measure
footcandles. He may mean lumens, or candlepower, or luminance. The pdf
link I posted is a good primer.

Getting blind here, but what .pdf-link was that? (I didn't see one.)


Thanks!

David

In article ,
Smitty Two wrote:
In article XHP%j.177183$Cj7.174287@pd7urf2no, "Calab"
wrote:

With all the talk about CFLs, incandescent bulbs and LED bulbs I was
wondering... Is there a device that can be used to objectively measure the
brightness of a light? Something I can use to compare bulbs in my home, auto
headlights, flashlights, etc?

You might start with this short primer on lighting terminology. Then
decide what it is you really want to measure.

http://www.energybooks.com/pdf/D1150.pdf

There it is!


But the newsreader I use, trn4, got me to the *later* than the one
I replied to earlier, saying "what pdf-file?".o

Could the order sent and the order received be different?



David

In article ,
Edwin Pawlowski wrote:

....
two windows give me all the light I want most of the time. Since about
early March, I've only turned the lights on maybe three times. Even then, I
prefer to use incandescent over fluorescent on the desk. In the shop, we
just installed fixtures with 6 T-8 lamps in them and they are very good
around machines.



What's a "T-8" lamp?

Thanks!

David

On Fri, 27 Jun 2008 01:31:34 +0000 (UTC), (David
Combs) wrote:

In article ,
Edwin Pawlowski wrote:

...
two windows give me all the light I want most of the time. Since about
early March, I've only turned the lights on maybe three times. Even then, I
prefer to use incandescent over fluorescent on the desk. In the shop, we
just installed fixtures with 6 T-8 lamps in them and they are very good
around machines.



What's a "T-8" lamp?


Sounds like the newer, thinner fluorescent tubes.

Thanks!

David

On Jun 26, 9:31*pm, (David Combs) wrote:
In article ,

Edwin Pawlowski wrote:

...
two windows give me all the light I want most of the time. *Since about
early March, I've only turned the lights on maybe three times. Even then, I
prefer to use incandescent over fluorescent on the desk. *In the shop, we
just installed fixtures with 6 T-8 lamps in them and they are very good
around machines.

What's a "T-8" lamp?

Thanks!

David


The 6 is the number of lamps in the fixture, the 8 is the diameter
of the tube (T=Tube)