 Poster: A snowHead
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can a yellow lens with 86% light transmission be better than a clear lens with 94% in flat light/fog?
if so.. how come?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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@bambi, because different light frequencies get absorbed to differing degrees by snow, so a yellow lens can increase perception of contrast.
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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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by filtering out some frequencies of light it increases the contrast in what light is presented to the eye (makes the dark bits darker etc).
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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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thanks for clearing that one up guys  I'd guess it's quite marginal though...
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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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@bambi, no, not at all, makes a big difference. Or at least, it can.
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You'll need to Register first of course.
You'll need to Register first of course.
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Funnily enough I have tested almost this recently - I recently got an amber lens with I think 65% transmission and a slightly mirrored clear lens with 85% transmission. In flat light the amber was better despite the fact that the mirror finish on the clear lens was supposed to deal with reflections etc - and that across a bigger difference in light transmission. My suspicion is that the clear lens is really for sports where you get less reflection (motorcross?).
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BTW - I have generally not bothered swapping lenses but my latest goggles came with a low transmission (40%?) / highly mirrored lens that is really too dark if it gets gloomy. I think the amber lens works for me in 95% of conditions - perhaps not extreme bright days late season.
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I think, @jedster, that clear lenses are for motorsport. And jungle warfare. Mirrored finish is anti-glare, I think.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Don't forget that everyone's eyes are different to varying degrees, so what works for someone else may not work as well for you, so you really need to test the effect of different lenses on snow. Try and borrow as many different goggles as possible when the conditions are bad.
Light transmission and filtered frequencies are different things, so you can get a dark black lenses which blocks 90%, and a light grey lenses which blocks 10%, but they both let through the same frequencies, so contrast would be approximately the same.
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Its all about the contrast...
Lets imagine a ski slope on a day where the light is flat... Why is it so difficult to ski? Well in short, flat or diffuse lighting tends not to lead to obvious shadows and hence you lose the ability judge depth or to define the topography of a surface - This is far from ideal when up a mountain!
What shadows there are (outdoors at least) tends to be sort of blue-ish as the yellow light from the sun is blocked from the shadow and the only lighting comes from indirect and reflected lighting. Yellow goggles prevent light in the blue region from passing to your eyes, whilst allowing other wavelengths to pass, meaning that our blue shadows appear significantly more black; basically increasing contrast.
The link below might be of intesrest and shows the use of filters in B&W photography.
http://technorobbo.home.comcast.net/BWCOMPARE.png
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