Light transmission?

[gogetter]

Ok optipros...i need some clarification/explanation please.

if a lens claim to have 30% light transmission what does that mean exactly? some of their other lens colors are 10%, 9%, and 14%.

what are some reasons you would prefer one over the other?

Which is better a higher or lower percentage?

[HarryChiling]

That means 30% of the light that reaches the lens is transmitted through it. Sunglasses generally have a lower transmission which is a good thing, clear lenses should have a higher transmission, Higher index lenses have lower transimissions that lower index lenses.

[FVCCHRIS]

G-15...

That's where the term G-15(and others) is derived from. It allows 15% of the visible light to penetrate the lens and reach the eye.

[Chris Ryser]

Another term....................

That's where the term G-15(and others) is derived from. It allows 15% of the visible light to penetrate the lens and reach the eye.

There is also another term that is used in Europe and most other countries which is absorbtion. This means , the lens absorbs a certain percentage, it is actually the reverse of the transmission.

If a lens absorbs 50% of visible light it would also transmit 50%. For the sale of sunglasses it is believed in Europe that a consumer understands the term of a certain percentage better than the term transmission.

Spectrometers can be set to give a reading in either way you prefer.

I also belive that the word G-15 is an old trademark of B&L like the TrueColor by AOCO and stands for their greyish green lens. You can tint that color to 30 - 50 - 75 percent or whatever transmission or absorbtion wanted.

[Darryl Meister]

G-15 was indeed a gray-green tint from Bausch & Lomb, meant to replicate the relative luminous efficiency of the human eye.