brightness

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RichD

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Feb 16, 2021, 6:07:09 PMFeb 16
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I was shopping for a flashlight recently, and naturally
noticed a trade-off between size/compactness and brightness.
The devices range up to 500 Lumens.

Human perception is logarithmic. So I wonder, at what
point, measured in Lumens, does apparent brightness
level off? For instance, imagine you're in a dark place,
and you want to blind an adversary. How many Lumens required?

I seek the brightest lamp reasonable, while at the
same time portable; pocket or belt carry

--
Rich

Phil Hobbs

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Feb 17, 2021, 8:59:31 PMFeb 17
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RichD wrote:
> I was shopping for a flashlight recently, and naturally
> noticed a trade-off between size/compactness and brightness.
> The devices range up to 500 Lumens.
>
> Human perception is logarithmic. So I wonder, at what
> point, measured in Lumens, does apparent brightness
> level off? For instance, imagine you're in a dark place,
> and you want to blind an adversary. How many Lumens required?

Lumens are like watts---they measure the total amount of visible light.
A good 100W incandescent bulb circa 2012 put out 1690 lumens. That's a
whole lot for a flashlight.

For a narrow-angle applications, you care more about lux (lumens/sq
metre). 1000 lux is a nice number for reading a book, but 5000 is better
for an old guy doing close work. ;)

For incapacitating somebody, you're much better off with an 8-D-cell
Maglite, know wha' I mean?

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

RichD

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Feb 22, 2021, 3:50:11 PMFeb 22
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On February 17, Phil Hobbs wrote:
>> I was shopping for a flashlight recently, and naturally
>> noticed a trade-off between size/compactness and brightness.
>> The devices range up to 500 Lumens.
>> Human perception is logarithmic. So I wonder, at what
>> point, measured in Lumens, does apparent brightness
>> level off? For instance, imagine you're in a dark place,
>> and you want to blind an adversary. How many Lumens required?
>
> Lumens are like watts---they measure the total amount of visible light.
> A good 100W incandescent bulb circa 2012 put out 1690 lumens. That's a
> whole lot for a flashlight.
> For a narrow-angle applications, you care more about lux (lumens/sq
> metre). 1000 lux is a nice number for reading a book, but 5000 is better
> for an old guy doing close work. ;)

The packages include the FL1 standard, but I don't know how to interpret
that. One of the specs displays a light cone, and e.g. '95 ft.' This indicates lux?

Then there's a picture of a light beam reflecting from the floor ...?

> For incapacitating somebody, you're much better off with an 8-D-cell
> Maglite, know wha' I mean?

One of those police torches - not too convenient for routine carry -
probly nice self-defense gadgets though - "It's a tool, not a weapon, officer!"

--
Rich

Phil Hobbs

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Feb 24, 2021, 8:56:08 PMFeb 24
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The ones all the rent-a-cops carry. Billy clubs are illegal, but
flashlights are OK.
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