The Saetto Lens Guide
No bad light.
Just the wrong lens.
Every lens on Earth answers two questions: how much light gets through, and which colors get through. Learn those two things — about three minutes — and you will never buy the wrong lens again.
Rule 01
How much light? That is VLT.
VLT (Visible Light Transmission) is the percentage of light that passes through the lens. Low VLT = dark lens. High VLT = light lens. Sunglasses are grouped into categories by law, from 0 to 4:
And UV400? That is the one non-negotiable. UV400 means the lens blocks UVA and UVB up to 400 nanometers — basically 100% of UV. It has nothing to do with darkness: a clear UV400 lens protects your eyes exactly as much as a dark one. Darkness is comfort. UV400 is protection.
Rule 02
Which colors? That is the tint.
Blue light scatters — it is why the sky is blue, and why cloudy days look flat and washed out. Tints that filter blue (yellow, rose, amber) turn the contrast back up. Neutral tints (grey) keep colors true. That is the whole science. Here is the map:
Dims bright sun without changing colors. The neutral all-rounder for full sun.
Cuts blue, boosts depth and ground texture. Great in changing light and behind the wheel.
Comfortable all-day middle ground: real colors with a touch of contrast.
Barely darkens, strongly sharpens. Dawn runs, fog, heavy overcast. Not for nighttime driving.
The endurance favorite: high contrast with high comfort, from dawn to changing afternoon light.
A shield, not a shade: wind, grit, bugs and night rides — with full UV400 anyway.
A reflective outer coating that bounces excess light away. The color you see is the coating — the tint underneath does the filtering.
Same physics as any mirror, maximum style. Works hardest in harsh summer light.
Darker up top, lighter below: sky filtered, ground and dashboard easy to read.
Pick by your hour
Match the lens to your light.
Cat 3, smoke or mirrored. Midday, beach, summer pavement. Mirror coatings add anti-glare punch.
Polarized. Kills the white flash bouncing off water, glass and hot asphalt. Calm, sharp view.
Yellow, rose or amber, cat 1–2. The problem is missing contrast, not too much light.
Light rose or yellow. Turns weak, fast-changing light into a readable scene.
Clear. Always. Any tint steals light your eyes need. Clear still blocks wind, bugs and UV.
Interchangeable lenses (or photochromic). Swap the filter instead of compromising all day.
The polarized question
Polarized: when yes, when no.
Say yes for
- Driving — windshield and asphalt glare disappear
- Water: fishing, beach, boats — see through the surface
- Everyday city wear — glass buildings, chrome, comfort
Think twice for
- Fast running and road cycling — that glare on the road is information: it warns you about water, oil and ice
- Sports watches and bike computers — LCD screens can black out at an angle
- Technical trail — depth cues can flatten
That is why competition lenses across the industry usually skip polarization on purpose.
Quick corrections
Three myths, busted.
“Darker lenses protect more.”
No. Protection is UV400, and a clear lens can have 100% of it. A dark lens without UV protection is the worst of all — your pupil opens wide and lets more UV in.
“Yellow lenses are for night driving.”
No. Controlled studies found no benefit at night — every tint removes light your eyes are already short on. Yellow shines at dawn and in fog, in daylight. At night: clear.
“A blue lens filters blue light.”
Usually it is a blue mirror coating over a neutral tint. The coating is the look; the tint underneath does the work.
Make them last
Lens care in 30 seconds.
Do
- Rinse with clean, lukewarm water first — dust scratches when wiped dry
- Dry and polish with the microfiber cloth only
- A drop of mild soap for sunscreen and fingerprints
- Store in the pouch or case, away from heat
Never
- Shirts, towels or paper — they micro-scratch mirror coatings
- The car dashboard — heat warps frames and damages polarized filters
- Household glass cleaners or alcohol on coated lenses
- Placing them lens-down on any surface
Mirrored and polarized lenses are the most sensitive of all — the coating and the filter live on thin layers. Treat them with the cloth and the case, and they stay sharp for seasons.
Still not sure? Tell us when and where you train — @saettoeyewear — and we will answer with a lens, not a sales pitch. No bad light.