What does it mean to have 30×60 Binoculars?

I had to buy these tiny “30×60 Compact Folding Binoculars” because I wanted to know what “30×60” means and if that thing was any good. It is sold by different companies under different names and sometimes with very different specs. But it looks like it was made in China by the same factory.

You can find it for as little as $10 if you look around, which is crazy. That’s how much two thin plastic lenses on a cheap pair of sunglasses cost. How can something so cheap have three or four lenses and a prism? Many people who know little about binoculars buy them because they are cheap. But can you trust such cheap binoculars to work and give you at least some optical performance, or are they just a bad toy?

What does 30×60 binoculars mean

That’s a really good question, and I was also curious about what “30×60” meant. When you look at the specs of these tiny binoculars, it gets even more confusing. Most of the time, the numbers that stand out on binoculars are about the magnification and the size of the collecting lens.

The first number is the magnification, or how many times bigger an object looks when it is looked at. The second number is the diameter of the objective lens in millimeters. This is the big front lens that faces the object. At first glance, you can see that the front lens of this model of 30×60 binoculars is not 60mm (2.36 inches) in diameter.

So, the “30×60” must be a marketing trick to make the binoculars stand out from other cheap compact binoculars. Most likely the same with Day and Night Vision. 

Even though it doesn’t say so on the binoculars, they are 821, with an 8x magnification and a 21mm objective lens.

Specs Of The 30×60 Binoculars

The objective lens is easy to measure. And I can determine the magnification by how big the field of view is. The field of view is 7.2 degrees, and the “meter value” can be found by multiplying that number by 17.45. I get about 126 meters, which the instrument says I should get. About 8x magnification equals a field of view of 126/1000 m.

The 30×60 binoculars have standard optical glass and a crown lens coating.

BK7 Magnification systems with fully coated prisms

8x: The diameter of the lens’s objective is 21 mm

Exit pupil 2.6 mm

Eye relief 5 mm

126/1000m 378/1000yrd

Focus up close at 15 feet (5 meters)

The Twilight Factor is 12.96.

Resistant to water

IPX6 means it won’t get wet.

Weight 5.1 oz

First General Impression

The first impression isn’t bad when you take the thing out of the box and hold it in your hand. When you hold it in your hand, it looks pretty good and feels pretty solid. When the barrels are folded apart, nothing shakes, wobbles, or comes loose, and the hinges are also good. The center focus wheel isn’t very big but turns slowly and smoothly.

For how small it is, it feels heavier than you’d expect. This is because the barrels and middle bridge are made of aluminum when you’d expect plastic. You wonder how they can do something so cool for so little money. But how good are the looks, and how well does it work?

Mechanics

As I said, the case feels solid, and nothing moves around. It is made of aluminum, and the hinges and barrels work perfectly. The barrels can be folded easily to change the distance between the eyes. The Center Focus wheel turns easily, and there is nothing wrong with how it works. The right eyepiece has a diopter correction, but it doesn’t say what the values are. Instead, it only has + and -.

Optics

The Optics 821 Binoculars are small and simple to use. They don’t weigh much, and you can put them in any pocket. Binoculars with a magnification of 821 can be used during the day to look at distant things, events, or happenings.

When buying small, compact binoculars, you should pay attention to how well they are made and how good their optics are. The lenses, especially the objective lens, should have good coatings that let enough light through so that the images can be seen clearly.

Vision at night?

821 is good during the day but not useful at night unless what you want to see is very well-lit. Night vision usually means amplifying the light that is still there. This model does not have that.

For binoculars to work well in low light, the objective lens must be big to gather much light. A big lens ensures that the twilight factor is high and the relative brightness is high.

Only 12.96 and 6.8 for the Twilight factor and Relative brightness, respectively. Both values should be around 15 or more for the binoculars to be good for night use.

Have a pair of binoculars with a large exit pupil that can be used at night. When it’s dark, a person’s pupil opens up to more than 5 mm to let in a lot of light. The exit pupil of an 821 pair of binoculars is just over 2 mm, which is not much for using them at night.

Ruby red coating on the lens

Wow, the lens coating is ruby red. It looks nice, but…

As I just said, good coatings greatly affect the image’s brightness because they let more light through.

The coating on the objective lens looks great because it is ruby red. It is meant to increase the contrast of the image seen in bright sunlight by filtering out most of the red parts of the light. But this only works in glasses that are good. The warm red parts of the spectrum are also filtered out, which makes the image look colder and bluer.

When the optics aren’t very good, filtering out the red helps reduce color aberrations because the red isn’t there. Because the red coating reflects light so well, the binoculars are also less useful in low light. It looks nice, but that’s all.

Prisms

When you hold the binoculars out in front of a light background and look at the exit pupil, it looks round all the way around. This is a good sign because it shows that BaK4 glass prisms should be used. Amazing how cheap it was.

People do look at a straight line. When you turn it around and look at the lens from the front, you can see it even better. You can’t see anything off the line when you use the binoculars normally. This can only be caused by the roof prism, where the two glass blocks don’t seem to fit together perfectly; there must be a small space between them.

Eye Relief

This is the distance between the eyepiece and where the image seems to be when it is looked through. This is important for people who wear glasses because they can’t hold the binoculars as close to their eyes. If the eye relief is too short, you can only see a partially darkened image. With a 5mm eye relief, this instrument is not good for someone who always needs to wear glasses.

If you always have to wear glasses, ensure the binoculars you buy have enough eye relief. Only then are they good for people who wear glasses? It’s important to try different models to see which gives you the best viewing comfort.

Collimation

My model’s two binocular tubes are not perfectly lined up with each other. This isn’t very obvious to the naked eye. So that the brain can put the two images together, the difference is small. But if I open my eyes alternately, I can see that a targeted post doesn’t show up in the same place but is slightly off.

Lower-priced binoculars only go through random quality checks; not every model is checked to ensure it works and is perfectly assembled.

Blurring the edge

Expect the edges to be blurry and the picture to be distorted near the edges. The images are only sharp in the middle. The blurring starts halfway through the field of view and progressively worsens toward the edges.

Chromatic Aberration or Color Fringing

You can clearly see chromatic aberration when you look at branches against a bright sky or a power pole against a light background. Because of the red coating, red isn’t as noticeable, but you can see blue and greenish-brown edges where light and dark meet.

Fidelity to Color

As was already said, the lens’s ruby-red coating blocks out the light’s red part. This causes a shift toward blue, which can be seen as a blue haze over the images.

Pros

Strong body and smooth workings

Very little and tight

Compensation for diopters

Case to carry it in, a string for a neck strap, and a cloth to clean it.

Very inexpensive 

Cons

Poor sight

Edge blur

Fringes of color

Conclusion

In short, for the low price, you can’t expect much. But if you look more closely and consider how cheap it is, you must agree that they did well. Hard to believe.

The aluminum case is strong and has a rubber coating that keeps it from slipping and protects the instrument slightly. The focus wheel and diopter compensation, which is mechanical parts, work smoothly and evenly.

Due to the low price, the optics leave a lot to be desired. This is because the image is only sharp in the middle of the field of view, the edges blur, and chromatic aberrations are very clear.

The images were not the brightest with a 21mm aperture and the used glass. It works well enough for daytime use, but you don’t need night vision to use it at night.