Are ED Glass Binoculars Better Than BAK-4 Binoculars?

 

 

When we choose binoculars no doubt we want to choose the best one for our money. Some of them are cheap, others are costly.

This is very understandable. Everyone make their choice depending on the budget.

When it comes to choosing BAK-4 or ED glass binoculars, it looks like for many people it’s a kind of a mystery that many want to figure out.

And this is what we are going to do today in this short educational post.

 

There are mainly three type of prisms used today in binoculars. Depending on the prism used in a binocular price may differ a lot.

There are 3 types of prisms:

• BK-7
• BAK-4
• ED Glass

 

 

BK-7 Prism Binoculars

BK-7 prism is the cheapest one and the image quality in such binoculars far from being perfect. It’s still not bad. I would say it’s acceptable.

The image you see in BK-7 binoculars is not as bright and clear as you see in BAK-4 binoculars. Borosilicate glass is often used in BK-7 prim binoculars.

On the image below you can see the difference between BAK-4 and BK-7 binoculars. The image says more than words.

Generally speaking I never recommend BK-7 prism binoculars because of the low quality image.

Such optical instrument can be recommended only if you are on a tight budget and want a pair of binocular for general use purposes.

 

 

BAK-4 Prism Binoculars

BAK-4 prism binoculars are very solid optical instruments that deliver high quality, bright and crystal clear image thanks to Barium Crown glass used in the optics.

It’s used even in high-end binoculars for several hundred bucks.

You must also keep in mind that Chinese BAK-4 prism very often means Schott PSK3 which is in fact phosphate crown glass while premium quality BAK-4 prism uses Barium Crown glass.

These two things are not the same and it significantly affects the image quality in the binoculars.

Crown glass has low dispersion which its around 60 Abber number or aka V-numbers. It’s known as a measure of dispersion used in optics.

6o is a high number which means quality optics. In some expensive binoculars this number can be as high as 75 or even 85 used in some phosphate crown glasses.

 

 

 

Cheapest ED Glass Binoculars

 

 

ED Glass Binoculars

ED Glass binoculars are the most expensive optical instruments because of using highest quality of optics in the binoculars.

They provide the best image quality you can ever see when looking through binoculars.

This is achieved thanks to reducing chromatic aberration to the maximum.

Technically it is achieved thanks to using concave lens of flint glass combined with a convex lens which produces achromatic doublet.

In the end thanks to using ED Glass in the binoculars you get super quality image that has no chromatic aberration or in other words without color fringing.

 

 

I can’t say this color fringing is very noticeable when looking through binoculars. In some binoculars it’s very noticeable, mainly in cheap binoculars.

In high end binoculars it’s not. But for professional users it may be important which is why they prefer to choose ED glass binoculars.

 

 

 

Lens Used in Binoculars

There are three types of lenses used in binoculars:

 

Compound lenses – Single lens type that consists of a single optical element. This type of lens can’t do much to correct chromatic aberration

 

Achromatic Doublet – Compound lens. This type of lens is made of a low dispersion glass and consists of two optical elements.

 

 

This lens does reduce chromatic aberration significantly but it’s not a perfect solution.

 

Apochromatic Lenses – Consists of three elements and does a great job to not only reduce chromatic aberration but also provides an image that has almost zero of color fringing.

 

 

 

Is there any visual difference between BAK-4 and ED Glass?

Yes, there is a difference. As I mentioned above, there is a difference between standard BAK-4 and ED Glass binoculars.

Both provide bright, clear and sharp image but ED Glass has no chromatic aberration or in other words color fringing.

But is there any difference among ED Glass binoculars?

Yes, there is a difference. Not all ED Glass binoculars are same. The quality of image depends on lens coating used in the optics.

All this is done to minimize chromatic aberration.

Binoculars with ED Glass that cost $200-$300 can’t deliver the same image quality as binoculars with ED Glass that cost around $1.000.

This is very obvious because in high end models manufacturers of optics use advanced lens coating.

All this is done to provide not only bright, clear and sharp image but to deliver image with no chromatic aberration at all.

 

 

 

ED Glass Binoculars

 

 Vortex Optics Razor HD Roof Prism Binoculars, 10×50

– Wide field of view
– Magnification power 10x
– Fully multi-coated high quality optics
– 82% Customer satisfaction
– Price: $1,088

 

 

 

 

 

  Vortex Optics Razor HD Roof Prism Binoculars, 8×42

– Wide field of view
– Magnification power 8 x
– Fully multi-coated high quality optics
– 82% Customer satisfaction
– Price: $1,279

 

 

 

 

 

   Vortex Optics Kaibab HD Binoculars, 18×56
– HD Water Proof Roof Prism
– Magnification power 18
– Customer satisfaction: 85%
– Price: $998

 

 

 

 

 

 

  Vortex Optics Ranger HD R/T Binoculars 10×50
– Wide field of view
– Magnification power 10x
– HD premium high quality optics
– Customer satisfaction: 100%
– Price: $799

 

 

 

 

 

 

 Pentax ZD 10 x 43 ED Binoculars – Roof prism

– Phase-corrected Bak-4 Prism, Waterproof, Fogproof
– Magnification power 10, Extra low-dispersion glass
– Customer satisfaction: Yes
– Price: $1,399

 

 

 

 

 

  Swarovski SLC 10×42 Waterproof Binoculars

– Wide angle of view (61-degree apparent field of view)
– HD Glass Prism
– Magnification power 10
– Customer satisfaction: 100%
– Price: $1,799
– 10-year warranty

 

 

 

 

 

Wingspan Optics Skyview Ultra HD – 8X42

– Wide field of view
– Magnification power 8x
– Extra-Low Dispersion ED Glass
– Waterproof, Fogproof
– 94% customer satisfaction
– Price: $157

 

 

 

 

 

 

 

  Wingspan Optics Phoenix Ultra HD – 8X42 Bird Watching Binoculars with ED Glass

– Wide field of view (Field of View: 393 feet at 1,000 yards, 7.5 degrees angle of view)
– Waterproof/Fogproof
– Magnification power 8x
– Prism: Bak-4, ED Glass
– 93% customer satisfaction
– Price: $159.92

 

 

 

 

 

  Wingspan Optics Thunderbird Ultra HD – 8X42 Binoculars

– Wide field of view (Field of View: 420 feet at 1,000 yards, 8 degrees angle of view)
– Waterproof/Fogproof
– Magnification power 8x
– ED Glass
– 91% customer satisfaction
– Price: $249.92