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Archive for the ‘Binoculars’ Category

Testing out the Carson HookUpz IS-100 Universal Smartphone Optics Adapter

Carson Optics has introduced a new product to the world of Smartphones. The HookUpz Universal Smartphone Optics adapter. This is a device that hopes to make the now nearly ubiquitous Smartphones even more useful to hobby and industry as it is supposed to allow you to attach almost any Smartphone to almost any optical system (microscope, binocular, telescope).

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But that brings the question: Does it work? We’ll we spent some time fiddling with one to find out!

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Cleaning Optics – How to do it.

So in our previous entry we talked about what not to do when cleaning sensitive optics such as telescope lenses and binoculars. Now it is time for a better explanation of how to properly clean those optical lenses. Note that everything mentioned here can be applied to binocular lenses, telescope lenses, and even camera lenses.

Before we discuss specific cleaning methods let me state the first rule of lens cleaning, similar to Hypocratic Oath:

DO NO HARM!

If your lenses are not dirty, don’t clean them for the sake of cleaning them.  If a tiny smudge is on your lens but isn’t showing any effect on viewing, just let it be. All too many lenses have been damaged or destroyed by unneeded cleaning.  So consider carefully before starting the cleaning process.

We are going to discuss two methods of cleaning optics: using a cleaner and lens tissue and using a Lens Cleaning Pen. Let’s start with the latter.

Method 1: Lens Cleaning Pen

Lens cleaning pens are sold under a variety of names but they mostly have the same features: A soft dusting brush and a flat cleaning end. The first thing you will do is brush the lens gently with the brush end.

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Cleaning Optics, what not to do: Telescopes & Binoculars

So say you have a nice pair of binoculars or a good refracting telescope (or spotting scope). One day you are about to use it and you discover some kind of smear 102on the front lens.  Perhaps it was a droplet of water from the day you were viewing and a small rainstorm brewed up? Doesn’t matter, you need to clean that lens or otherwise your view will be very diminished. So you grab a tissue from the bathroom and some window cleaner and….

STOP

OK, let’s talk about glass and the things we put on it to see better. Glass is a fairly hard material but it can be scratched, but a greater concern for your nice binoculars is the coatings on the lenses. You might notice that purple/green/blue coloring in the reflection if you look at the lenses at an angle. These coating are very important to the binocular/telescope’s optical quality and you cannot just use anything to clean them.

Why?

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New Planet Maps

OK, technically one of these is actually a Moon Map but let’s not quibble on semantics . These new Maps from Orion are a great way to get the most out of planetary viewing with your telescope. The first up is the Moon Map 260

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10 Fun Facts about Binoculars

Most people have a set of them, but do you know all about them? Here’s 10 fun facts about binoculars

10) Although the invention of binoculars goes back to the late 17th century, their use for terrestrial viewing (looking at things on earth) did not become 3480common until the late 19th century. This was thanks to the use of internal prisms to ‘erect’ the image viewed in the binoculars. Prior to this development binoculars were mostly for astronomy use.

9) Binoculars often are described with two numbers, such as 7×50, or 10×35, etc. The first number is the magnifying power of the binocular – so 7x will magnify thing 7 times. The second number is the aperture (diameter) of the front lens in millimeters. The larger the aperture the better the image will be but anything over 50mm will be hard to hold comfortably.

8) There is an upper limit to most hand-held binoculars’ magnification. 10x magnification is about as much as the average person can hold steady for any length of time. If you try to hold 12x or higher power binoculars with your hands you will probably shake too much to view anything easily. High powered binoculars should be mounted on a tripod.

Binocstripodadapter7) Speaking of tripods, ever wonder how to attach binoculars to a camera tripod? You need a low-cost tripod adapter, then find the cap cover that is between the two openings of the binoculars. It either snaps off or screws off. Once that is off you can thread the adapter into the binocular and thread the adapter into the camera tripod. Unless your binoculars are very old these threads are pretty much universal (1/4″-20)

6) There are two major designs of binoculars, and they are named by the prisms they use. The first is known as ‘Porro-Prism’ and uses a pair of right angle 5186prisms to rotate the image. This is the standard, wide-body binocular most people are familiar with. The 2nd design is what is known as  ‘Roof Prism’ where a more straight and compact Abbe-Prism is used to correct the image. Roof prisms are used in most compact models (the ones which seem to be just two straight tubes with a hinge connecting them).  Roof prisms are more compact but there are issues with the compact prisms such as light loss, color separation and other issues that mean they require higher tolerances or special phase-correction coatings to resolve the issue.

5) Coatings! These are very helpful for binoculars. Every time light goes from air-to-glass it can lose 7-9% of the light being transmitted. Given that there are at several such points in a binocular (the main lenses, prisms, eyepieces) you can lose quite a bit of light without coatings. A basic coating can bring light loss down to 5-6% and multi-coats can bring the loss down to 3-4%. Most good coatings should be blue in color or greenish/purple (which is better because it indicates a multi-coat). Stay away from Red or ‘Ruby’ coatings. They wash out colors.

4) Binoculars can be damaged by cracking or breaking the lenses (very hard to repair). Smudges, smears, or other items on the lenses (easy to clean with proper care and tools), and alignment issues where the two sides of the binocular end up not being in collimation (aligned properly, a tricky but not impossible fix). Most binoculars are pretty durable but they do go on adventures since people carry them while hiking, climbing, etc.

3) Stabilized binoculars are available for those with shaky hands or on a surface where a tripod is not practical (such as on a boat). They are not cheap and operate by using gyroscopes to compensate for movement of the binocular.

2) A little over 10 years ago, several companies came out with binoculars with gadgets attached. One common one was a built-in radio with headphones, DigitalBinobut far more common were digital cameras mounted in between the lenses. This was something of a deception as these were usually cheap digital cameras and the impression they tried to give was that what you saw through the binoculars was the image you’d get in the camera. This didn’t work as the only way to match the magnification of the binoculars was to use the ‘digital magnification’ which as any expert in digital photography will tell you is cheating.

1) When buying binoculars, consider the following: You do get what you pay for – up to a point. Up to around $500-$750 you truly do get what you pay for with binoculars. A $200 binocular is probably going to (subjectively) give you a twice as crisp and clear image as a $100 binocular. Once you reach the higher numbers the improvements will drop off rapidly. A $1,500 binocular will not be twice as good as a $750 binocular. In fact it may only improve (subjectively) 5-10%.

Want to buy Binoculars?

www.spectrum-scientifics.com

 

‘Military Spec’ Binoculars? Maybe yes, maybe no!

We quite often hear people talking about ‘military spec’ binoculars or just plain military binoculars. We’re not exactly sure what makes a binocular military, but from an milspecbinosexamination of google images for that search term it seems that that military binoculars posses at least one of the following characteristics:

  1. Green body color or other camo scheme
  2. Rubberized armored body
  3. No central focus wheel
  4. Built-in compass
  5. Thick binocular body frame
  6. Attached lens caps

You may notice what is missing in there: namely “actually used by one of the world’s militaries”. Sadly there are a huge number of manufacturers out there who think that just plopping one of the above features (or in the case of #3 lack of features) they can call them ‘military’ or ‘tactical’ or ‘mil-spec’. (more…)

Optical Coatings – Why they are important and what to avoid

Take a look at the front of any pair of binoculars, refractor telescope, or even most sets of eyeglasses and you might notice that they often have a blue, green, or even purplish tint to them. This is a sign of an Optical Coating.

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Optical coatings have vastly improved the quality of optics over the past decades. The reason for their existence is simple: Every time light goes from air to glass it loses as much as 8% of the light due to scattering/reflection. This may not sound like much but when you consider that a basic refractor telescope with an air spaced achromat (lens with two or more elements) and a decent two element eyepiece will have 4 air-to-glass transmissions. So thats ((((100%*.92)*.92)*.92)*.92) = 71.6%. You lose over 1/4 of the telescope’s light gathering power from scattering! That doesn’t include a mirror or prism diagonal which will also lose light! Binoculars have a similar problem, only more so as they have internal prisms that add even more air-to-glass transmissions. (Eyeglasses do not need coatings so much, but they do not cost too much and usually don’t hurt to add).

Hence optical coatings were developed. Coatings do not solve the light scattering problem, but they sure as heck reduce it. A decent coating can reduce the light scattering from 8% loss to around 4-6%. Adding even more layers, or multi-coatings improves the scattering reduction, as does the quality of the coating application. But nothing completely ends scattering.

Optical coatings in lenses are almost always made of Magnesium Flouride (MgFL). They are applied in a vacuum chamber. A single optical coating should have a very subtle blue color when you look at the lens surface at an angle. Multi-Coats will have a green or even purple tint when you examine the surface.

In all, there are several accepted classifications for optical coatings: Coated, fully coated, multi-coated, and fully multi-coated. They are defined as follows:

Coated means that at least one air-to-glass surface in the optical system has an optical coating.

Fully Coated means that all air-to-glass surfaces in the optical system have an optical coating.

Multi-Coated means that at least one air-to-glass surface in the system has an optical multi-coat. The rest should have at least a single optical coating.

Fully Multi-Coated means that all air-to-glass surfaces in the system have mutli-coatings.

There are some variations on this. In Europe optical multi-coats are often referred to as ‘Overcoated’. Adding further to the confusion is that some companies give names to their coatings. Sometimes this is warranted as the coating is somewhat different from standard coatings, more often it is just marketing.

There is a dark side to coatings, the worst of which is the abuse of ‘Ruby Coatings’ on binoculars. Ruby coatings first came out from Steiner Binoculars who are fond of making specialty binocular coatings for specific environments, such as hunting binoculars whose coatings that bring out objects better in foliage, desert coatings for the same purpose in the sandy zones, etc. One coating developed by Steiner had a ruby color. It worked acceptably, but it worked by partially blocking some of the wavelengths of light. The Steiner version did this only a little, but the resulting coating had a problem: It looked cool.

Ick! Ruby Coating!

Since the Ruby coatings looked cool, Hollywood and Madison Avenue started using binoculars in ads and movies with the ruby coatings. This turned out to be a bad thing as many low-end binocular producers started churning out ruby-coated binoculars by the container-load. But there was a problem: Ruby Coatings didn’t give you a very good image.

If you look through a Ruby coated binocular and compare it with a normally coated binocular you will see that it looks a little washed out. The greens and blues stand out too much, the reds are faded. Its like looking at a photo that has had some sun bleaching. This is because the red portion of the spectrum is being deflected by the Ruby coatings, which low-end binocular producers made with brighter and brighter red coatings that dropped more and more red light.

Eventually, it got to the point where you could not have a low-cost binocular without a Ruby coating. But soon the Ruby started to lose its value. Bird watchers knew that the drop of the red colors meant they could not see all the details in their favorite birds, folks wondered why so few higher end binoculars didn’t use ruby coatings if they were so good, some binocular sellers outright spoke out against ruby coatings. Soon many of the ruby coated binoculars started to show up with regular coatings. You can still find ruby coated binoculars, but they are usually sold at the lowest end, sometimes even with bad TV ads. These are usually sold on the basis of their ‘cool’ appearance to those who do not know better. If you encounter a pair of ruby coated binoculars, try to avoid them. They are not worth even their low end pricing.

Want to buy binoculars?

www.spectrum-scientifics.com