 Poster: A snowHead
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Interesting, I hope your change of practice prevents any future issues. What you were advised is entirely consistent with what we have been told, and consistent with forestry and land workers in this country being encouraged to wear clear but UV coated eye protection if they work for more a certain number of hours (I think eight) a week outdoors.
Yep...
UV protection = from coating on lens - including clear lens
VLT = visible light, usually after UVA and UVB has been filtered out
Contrast and depth perception = entirely subjective, but seems to depend on individual genetics and ocular history
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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As above, treat the "energy" as separate from sight enhancement. UV protection should be specified regardless of lens colour etc.
VLT is more preferential given good light levels as your pupil will modulate the light in response to the level you present them.
It's more critical as absolute at the highest and lowest range you are working in.
Lowest light level will ordinarily lead you towards highest transmission just to give you the most information to process quickly.
Red colour blindness could be one reason why some users don't see such advantage in lenses of that hue, giving obviously differing opinions as to the effectiveness.
Chromapop, prizm etc, as far as I'm aware are being used to market lens type that look most like dichroic filters. This, rather than dyed material (conventional?) seeks to split the light chromatic elements more concisely, for example blue reflected and yellow passing through, normally consisting of a "coating" as opposed to dyed substrate. It's pretty effective in doing it's job while also being so thin that it provides minimal disruption to the light's geometry. Usually this will preserve a higher focus, accutance, etc of the image in front of you by not unduly dispersing the light into scatter.
Put the colour purity and image geometry purity together and you can see the image results clearly with raised levels of physical detail and concise colour cut that you choose to best accomodate you own optical characteristics.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Visor helmet, pair of sunnies to hand if needed. No tunnel vision issues what so ever.
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Due to reflection from the inner & outer faces of the lens, the light transmission of a perfectly clear lens with no additives is 92%, the addition of enough additive (that costs no more than the polymer of the lens itself) to block 100% of the UV will drop the light transmission to about 90%. The UV protection is from additives within the polymer of the lens itself, not a coating.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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@ski3, is that what they're doing? Interesting, thank you. I knew it was a frequency selective filtering, but little more than that!
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You'll need to Register first of course.
You'll need to Register first of course.
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@under a new name, if you hold and tilt them in bright light they'll usually "flash" their complimentary colour as you move them, so green for magenta transmission lens for example. They may have a different outermost layer to improve acuity, similar to camera lens, this can also give you a colour flash as well.
Also why you have to take care not to scratch them as it can often go straight through the coating.
There's some impressive performers out there, and certainly worth those interested trying different specification to find one they're comfortable with.
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| ski3 wrote: |
| your pupil will modulate the light in response to the level you present them. |
Does a smaller pupil aperture therefore increase depth-of-field perception, as in a camera lens? i.e. would a lighter/clearer lens with greater VLT "stop-down" the pupil, and lead to an increased range of focus?
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| shep wrote: |
| ski3 wrote: |
| your pupil will modulate the light in response to the level you present them. |
Does a smaller pupil aperture therefore increase depth-of-field perception, as in a camera lens? i.e. would a lighter/clearer lens with greater VLT "stop-down" the pupil, and lead to an increased range of focus? |
Interesting point, my vision is not as good as it used to be but it is noticeably better in bright sunlight & I always like it well lit when I am working.
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FAQ
