I'd like to buy a cheap torch at least partially for self-defense. Even if I get attacked at night and robbed though, I DON'T want to damage anyone's eyes permanently. Only temporarily (5-30 minute range <EDIT: even 5-30 second range would be useful>) so I can make a hypothetical getaway.
To that end, I want to buy a particular torch which is capable of around 300 lumen (claimed 500). Because it is a 'zoomie' though, it is capable of generating a great of lux when focused to get its furthest throw. I was considering this torch: http://www.amazon.co.uk/gp/product/B00NPXCB7E/
I have a decent device to measure lux. Is there a graph to detail the relation between eye hazard (glare -> flashblindness -> eye injury) and amount of lux? I understand that the eye is much more sensitive to light at night, so presumably there is greater chance for permanent injury at this time? So ideally, the graph would be split into two components (one for night-time vision (when the eye lets the maximum amount of light in), and the other for bright daylight (when the eye lets the minimum amount of light in).
Failing such a graph, can anyone here give me a quick indication (in terms of lux) of what amount will merely cause glare, or more ideally causing temporary flash-blindness, versus causing permanent eye injury? Numbers would be good.
To that end, I want to buy a particular torch which is capable of around 300 lumen (claimed 500). Because it is a 'zoomie' though, it is capable of generating a great of lux when focused to get its furthest throw. I was considering this torch: http://www.amazon.co.uk/gp/product/B00NPXCB7E/
I have a decent device to measure lux. Is there a graph to detail the relation between eye hazard (glare -> flashblindness -> eye injury) and amount of lux? I understand that the eye is much more sensitive to light at night, so presumably there is greater chance for permanent injury at this time? So ideally, the graph would be split into two components (one for night-time vision (when the eye lets the maximum amount of light in), and the other for bright daylight (when the eye lets the minimum amount of light in).
Failing such a graph, can anyone here give me a quick indication (in terms of lux) of what amount will merely cause glare, or more ideally causing temporary flash-blindness, versus causing permanent eye injury? Numbers would be good.
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