Ever been in a situation where your scope lens keeps flaking and getting crazy colors? It can be pretty frustrating and you wonder if there is any solution to this. If you want to avoid these situations of annoying stains on your lens, psychedelic colors, and so on, then anti-reflection lens coating is the solution.
The purpose of AR coating cannot be overemphasized because they drastically reduce annoying glares, repel water, and reduce those crazy colors from reflections. So, thanks to the anti-reflective coating being done now, there are no worries about any reflection.
Now, let’s dive in deeper and discuss everything you need to know about anti-reflection lens coatings for your optics.
- What Exactly is Anti-Reflection Lens Coatings?
- The Application Means of Anti-Reflective Coating
- The Various Types of Lens Coatings
- The Quality of Coating
- The Right Choice of Coating for you
What Exactly is Anti-Reflection Lens Coatings?
When we talk about anti-reflection (AR) lens coatings, we are referring to the series of layers of adhesion to the front and back of your optic lens glasses. Or, the adhesion can be only behind the lens if it is a polarized one. Other names for anti reflective lenses are anti-glare glasses, anti-reflective glasses, and no-glare coating.
AR coating lenses are commonly found in a spotting scope, rifle scope, binoculars, laser range fires, prescription glasses, and even sunglass lens.
So, as the name implies, the function of the anti reflective lens is to drastically minimize the rate of reflection on different lenses. This anti-reflective ar coating is composed of metal oxides and every single layer consists of a thin film. This thin film is meant to obstruct a specified wavelength of light that helps reduce reflection. Once there is more of this layer, the wavelength will do more blockage of the specified light.
This blockage does not in any way reduce the way you see with your optic lens. Instead, since there is no reflection, it means that additional light will be getting to your eyes. Hence, enhancing your vision. So, you can consider this AR lens coating if you don’t mind going for a thinner lens.
The lens found in optics may be coated on one surface or even both surfaces. Now, the lens application can be done in a single layer or multiple layers.
In the world of AR coating, you can come across some of these terms. Get familiar with them and don’t get them confusing:
· Coated optics: coated optics deal with only one surface of the lens being coated. So, it is the most basic type of coated optics. This type isn’t so common in modern optics.
· Multi-coated optics: for the multi-coated term, we’re referring to at least one surface of one lens having multiple layers of lens coating. Usually, it’s the exterior surface of the lens that is multi coated. Then the other surfaces of the lens have at least one layer of lens coating. This means the inner surface features a single-layer coating.
· Fully coated optics: when it comes to fully coated optics, we have both surfaces of the entire lens to have at least one layer of lens coatings. This type of coated optics is good for short distance range but not so ideal for long distance range optics.
· Fully multi-coated optics: when it comes to fully multi-coated, every surface of the entire lens features multiple layers of lens coating. This is the real deal for high end lens coatings. So, being one of the best types of the anti reflective coating, you can find them on most serious tactical, sporting, as well as long range scopes.
The Application Means of Anti-Reflective Coating
The application process of AR coating tends to be pretty comprehensive and it involves vacuum deposition technology. Firstly, the lenses are carefully cleaned. Then the lenses are scrutinized for any noticeable issues or microscopic defects. Just a little smudge or a little hairline scratch found on the lens in the process of coating can predispose it to give a defective AR coating. Therefore, a good checking needs to be done.
So, in the process of production, multiple washing and rinsing baths are done. Also, ultrasonic cleaning is done to eliminate any sign of surface contamination.
Next, to further eliminate unnecessary moisture as well as gases from the surface of the lens, the lenses are heated and air dried in special ovens.
Then there are this special metal racks that feature this spiral-loaded openings. This is to securely hold the lenses. However, the lenses are held in a way that their surfaces are exposed for the AR coating application. So, the racks with the lenses are loaded into the coating chamber and the door of the chamber is sealed. Then a vacuum is generated by pumping out the air out of the chamber.
Now as the rack holding the lens rotates inside the coating chamber, there is a power source that focuses the beam of electrons onto a little crucible. This comprises a series of metal oxides found in different compartments. So, as the coating materials are penetrated by electrons, there is vaporization within the coating chambers. There is also adhesion to the lenses’ surface. This generates a uniform and microscopic thin optical layer on the lens.
There is some lens that possesses factory applied AR coating on the two lens surface. Then other types of lenses such as the progressive lens and other multifocal lens usually possess a coating that is applied after the lens customization.
The Various Types of Lens Coatings
To proceed further, let’s dig deep into the various types of lens coatings you can find.
Anti-reflective coating is surely important for any optics and they are industry standard. With this AR coating, reflection is drastically reduced and this enhances how you see your image in your rifle scope.
When there is a reflection of light, this causes light loss. Now you should understand that you can lose around 4 to 6 percent per surface. So, imagine you have as many as 10 surfaces in your optics. Now, think about it, when you add up 10 surfaces with 4 to 6 per surface light loss – that is drastically reducing your clarity. But this can be avoided with AR coating.
Anti glare will drastically minimize blurriness, contract, and reduce any difficulty in viewing fine details in your scope. Hence, you can see the importance of anti reflective coating in optics. Just one layer of this type of AR coating can minimize the loss of light by 1.5 to 2.0 percent.
Multi-Layer anti reflective coating
It’s true that single layer coatings were wonderful improvement to our optics. However, the world and technology is constantly evolving and as of these days, multi-layered AR coatings have become the standard for quality optics.
Coating that is single layered is only limited to work with certain light wavelength. However, multiple layered coatings enable the lens to greatly minimize any light loss over a wide variety of wavelength.
So, producers began the application of multi-layer anti reflective coatings to lenses just to further enhance clarity. Therefore, optics that are high-end tends to be extremely bright and clear so you can have a better shot when using your rifle scope or other optics.
Hence, when you have that high-end quality coating, the light loss can be greatly minimized down to 1 percent. The latest top-notch quality lens coatings can offer your rifle scope a light transmission of up to 95 percent.
Coating of water repellent
We also call this water repellent coating as hydrophobic coating. Now, this unique feature enables us to be able to see the image been viewed in our scope through any rain or moisture. Even if the moisture has accumulated on your scope, you can still get a better view of the targeted image. You may not even need to wipe down your scope because they can resist water and fog.
So, anti reflective coating or anti glare coating will not only offer you reduced glare, you will also get water repellent effect. This means even in the rain or under the fog, you will still get a good view and you can aim your shot and nail your target.
Abrasion resistant coating
Abrasion is something to be weary of when it comes to our optics. We don’t want to experience unnecessary scratches and abrasions with our rifle scope and other optics. Now, because of the nature of outdoor activities our optics are been used in, we can greatly benefit from an abrasion resistant coating.
With abrasion resistant coatings, you not only get protection for your lens, the anti reflection coating in your lens also gets protected. You will mostly find this coating in higher end tactical optics.
One company that transformed the industry of optics is Carl Zeiss company and they invented the phase-correction coatings. They created this for roof prisms in binoculars, spotting scopes, and so on.
This phase-correction coating gets rid of a problem called destructive phase shifts. This destructive phase shift occurs due to light waves reflection that occurs off opposite surfaces. Matter of fact, this occurrence happens because of the roof prism’s natural designs.
The Quality of Coating
You should know that coating quality varies. For instance, an optics that is fully multi coated that goes for $400 will be more clear than the fully multi coated optics that goes for $90. So, when we talk high-end glass, note that they should be relative to the range of your price.
The Right Choice of Coating for you
Selecting the coating of your choice will have you factor your budget. For instance, going for a fully multi coated optic will require you some extra cash. If you want that top notch optics that is great for distance shooting that will also enable you do so in low light conditions, then you should go for that quality fully multi-coated optics.
However, if your shooting range is only for a couple of hundred yards, then you can go for a multi coated optics. If you want something fairly affordable or you’re going for simple equipments such as a simple rimfire rifle, then you can go for a fully coated optics.
Therefore, no matter what your budget is, ensure you get the value for your money. This is why it will go a long way when you’re a little enlightened about lens coatings.
Brian Belko is a freelance writer and blogger. His primary areas of focus include the outdoors and shooting sports. In addition to his freelance work, Brian also writes for Wide Open Spaces and is on the Pro Staff at Military Hunting and Fishing. When he isn’t busy writing, Brian enjoys fishing farm ponds for bass and hitting the spring woods during turkey season.