The lens is
the product.
A sunglass lens does two separate jobs: it dims everything, and it removes glare. Tint does the first. Polarisation does the second. All five of these are polarised, so the only thing that changes between them is the tint.
| Tint | Finish | Polarised | Best light |
|---|---|---|---|
| Grey | Tint | Yes | Flat bright sun, driving, everyday |
| Brown | Tint | Yes | Variable light, hiking, judging distance |
| Dark Blue Mirror | Mirror | Yes | Open water, midday sun |
| Ice Blue Mirror | Mirror | Yes | Water, snow, high glare |
| Red Mirror | Mirror | Yes | Patchy light, cycling, ball sports |
There is no transmission column because no one has put these on a spectrophotometer. The millimetres elsewhere on this site are the frame maker's published figures; a transmission percentage is not among them, so it is not here either.
What polarisation removes
Sunlight arrives unpolarised, vibrating in every orientation at once. When it strikes a flat surface at a shallow angle the reflected portion comes away vibrating mostly in one plane, horizontally. That is glare: a bright, structureless veil that carries no information about what is underneath it. A polarising film is a sheet of aligned molecules that absorbs light vibrating along its axis; set horizontally, it removes the horizontal component. Everything else passes.
The effect is strongest at roughly 53 degrees from vertical, which is about where the sun sits mid-morning and mid-afternoon. It is why polarised lenses feel dramatic on water and merely pleasant at noon.
Two journal posts go further: polarized vs non-polarized on when the filter helps and when it does not, and UV400 vs polarized on why the two labels are separate claims.
What tint removes
Tint is bulk attenuation with a bias. A neutral grey takes the whole visible spectrum down evenly and leaves colour relationships intact. A brown lens removes more blue than red, which raises apparent contrast because blue is the wavelength that scatters most and flattens distance. A mirror adds a third mechanism: it reflects part of the light at the front face before it enters the lens at all.
The five tints
The lens colour guide puts all five side by side with the light each is for.
Questions, answered
What does polarised mean?
Light reflected off a flat surface such as water, a road or a car bonnet becomes horizontally polarised. A polarising film absorbs that one orientation and passes the rest. The glare disappears and the rest of the scene is untouched, which is why the water suddenly has a bottom.
Which tint should I choose?
Match it to the light you are standing in. Grey for flat bright sun, driving, everyday; Brown for variable light, hiking, judging distance; Dark Blue Mirror for open water, midday sun; Ice Blue Mirror for water, snow, high glare; Red Mirror for patchy light, cycling, ball sports.
Does a darker lens protect better from UV?
No, and this is the one worth knowing. UV protection comes from the lens material and its coating, not from how dark the tint looks. A very dark lens with no UV filter is worse than no lens at all, because your pupil opens behind it and lets more UV in.
Does a mirror make a lens darker?
It reduces what gets through, because part of the light is reflected at the front face instead of entering the lens. By how much depends on the coating, which is a figure we do not have for these and therefore do not quote.