Coating Colour

jermng · Post by **jermng** » Wed Feb 01, 2006 10:10 am

Hi,
Just curious, which colours are good to see in binocular coatings? Green? Blue? I know red is out ...
How many different kinds of coatings are there (colour)? How do you tell if something is single-coated or multi-coated or FMC?
Does this rule apply to other optical equipment like telescopes/EPs too?

Thanks for for any tips!

Canopus Lim · Post by **Canopus Lim** » Wed Feb 01, 2006 10:35 am

The coatings are Anti Reflection (AR) in short; by having less light energy reflected means more light transmitted. Therefore better coatings mean less reflection. If you shine a light to the lens, and less light is reflected (meaning the light source reflected off the lens is dim) the better is the coating.

jermng · Post by **jermng** » Wed Feb 01, 2006 10:54 am

Thanks Canopus. I know that coatings are there to increase light transmission ....
What I meant was, when you look into bino lenses from certain angles, you'll see different colours. Different colours are supposed to mean different kinds of coatings .... wanted to find out what they meant. =)

denebman · Post by **denebman** » Wed Feb 01, 2006 11:29 am

The best coating is the one with the least reflection and has not much to do with what kind of fancy color it appears from a certain viewing angle. Looking down into barrel of a fully multi-coated Fujinon FMT bino, I can perceive a dark green reflection but seldom can I see my own face reflected. My first russian made bino, which has a typical single-layer MgF2 coated lens, shows a light baby blue reflection and my face clearly.

alvinsclee · Post by **alvinsclee** » Sat Apr 01, 2006 11:03 am

Hi,
I agree with denebman that 'coating colour' does not relate directly to light transmission efficiency.

The common perception that red coating is not advisable for binoculars comes more from the nature-watching community. Most nature watchers are not in favour of red coatings because the colour will scare away some animals at dusk or night... a pair of large, red and round reflection may be perceived by these animals as retinal reflection from their predators.