What does diameter mean?
The amount of light passing through the different lenses of the binocular depends on the diameter of those lenses. The objective lenses are located at the front of the binocular. The diameter of the objective lenses are measured in millimeters. An 8x21mm binocular has an objective lens diameter of 21 millimeters. The larger the diameter of the lens, the more light they will gather. More light means a brighter image of greater detail and clarity. The size of the exit pupil also affects the brightness of an image. The exit pupil is the diameter of the beam of light, in millimeters, that passes through the eyepieces (oculars) of the binocular. The larger the exit pupil, the brighter the image becomes. Keep in mind however that larger lenses mean larger binoculars, which can become bulky and cumbersome. Most people are willing to sacrifice the slight differences in brightness in return for a compact, more manageable model.

What is field-of-view?
The field of view is the size of the area that can be viewed through the binoculars. Field of view is measured in two ways, angular field of view and linear field of view. The angular field of view is measured in degrees. Linear field of view is the width of area, in feet, visible at one thousand yards. Remember that the higher the power of your binocular, the smaller the field of view will be. In most cases, the larger the field of view, the poorer the image clarity becomes, especially around the edges. Bear this in mind when making your choice. Bigger does not always mean better!

Does the type of prism used make a difference?
There are prisms located inside binoculars that function to flip an inverted image upright. There are two common styles of prisms used; the BK-7 and the BAK-4. The BAK-4 prism is made of a higher density glass and can produce sharper images than a BK-7 prism can. If you are unsure as to which prism is being used, hold the binoculars out in front of you and look through the eyepiece. If you see a square shaped beam of light, chances are a BK-7 prism is being used. A round beam of light indicates the use of a BAK-4 prism.  

What are the purpose of lens coatings?
All the optical components of binoculars (the objective lenses, oculars, and prisms) should be coated to minimize light loss and reflection problems inside the binocular. A poorly coated binocular can lose up to 50% of the light initially gathered through the objective lens, resulting in a poor quality image. By coating the optical components with a fine film of certain chemicals, light loss can be greatly decreased. The highest quality binoculars have multiple coatings on all the optical components. These are known as "fully multi-coated" binoculars. These binoculars have the least loss of light and the result is a higher quality image.

What is eye relief?
Eye relief is the distance, in millimeters, a binocular can be held away from the eye and still see the entire field of view. If you wear glasses, a longer eye relief would be advantageous since your eyes cannot get as close to the eyepiece.

How can I get the most out of my binoculars?
Once you have chosen a binocular that is right for you, there are several things you can do to ensure that you are getting the most out of your binoculars. Thoroughly check your binoculars when you first buy them. Make sure there are no scratches, dents, or any other obvious damage to the unit. Check for image clarity, brightness and ability to focus. If you see blurred or double images, your binoculars may be damaged or poorly made.  

What steps can I take to maintain my binoculars?
Make sure your lenses are clean at all times. Keep them free of fingerprints, dirt and debris. Use a Carson LensPen to clean your lenses quickly and safely. When not in use, always replace the lens caps and store your binoculars in a case.

How do I focus my binoculars properly?
There are several steps you should take to focus your binoculars. The first step is to close your right eye and look through the left side of the binocular. Turn the center focusing wheel until you have a sharp image. Then close your left eye and look through the right side. Turn the dieter eyepiece until you have a sharp image in that eye. Last, look through both eyepieces and use only the center focusing wheel when looking at objects at different distances. Now you are ready to fully enjoy your binoculars.  

NIGHT VISION

What is the effective viewing range of the night vision device?
Viewing range varies anywhere from 10 to 400 feet. The maximum viewing distance greatly depends on the outside conditions. Such occurrences as overcast conditions, fog, rain, etc. may greatly reduce the effective distance of a night vision viewer.

Can I use the night vision device in extremely low light, or absolutely no light?
While it is true that your Night Vision device needs some available light to work, it is still possible to see a bright image in low light or no light situations with the use of an infrared illuminator, which is standard on our FoxBat models.

What type of light source can be harmful for a night vision device?
Your night vision device is intended for viewing objects in the dark, therefore, it may be harmful to use it during the daytime, or whenever there is a sufficient amount of light to see the object. Also keep in mind that strong direct light, such as projectors, car head lamps, strong flashlights and so on, may be harmful to your night vision unit.

How do I focus a night vision device?
It is recommended to start focusing from the eyepiece (ocular lens) and then move to the front lens (objective lens). You may have to adjust each lens several times before getting a sharp image.

Are FoxBat products shockproof?
No. Night vision products are sensitive to impact and should be treated as carefully as you would a photographic camera or a camcorder.

Can the night vision device and/or infrared illuminator be harmful to a person in any way?
Night vision devices are shielded, and do not produce any danger to the human eye and/or skin. Individuals with sensitive eyes, and those who experience eye pain while watching TV, may experience some eye fatigue if they use their night vision viewer for a prolonged time.

When I am using my night vision device, I sometimes hear a buzzing sound. Is it normal?
Yes. The buzzing sound is quite normal, and unless it is affecting the performance of your night vision viewer, it is not considered to be and imperfection. It is the power supply working to produce and image on your intensifier tube which is then picked up by the ocular so that you can see what you are looking at.  

Can my night vision device be used as a thermal imager?
Night vision devices are passive and operate as a light amplifier, which assists you in viewing in dark conditions. It cannot detect heat which is the technology behind thermal imaging.

Is the FoxBat waterproof?
No. Exposure to water and other liquids and even high humidity may cause damage.

Would it be harmful for the night vision device to pass through an airport x-ray checkpoint?
It is absolutely safe to pass your night vision device through the baggage security check at the airports.

What type of batteries does the FoxBat use, and how long will the batteries last?
FoxBat products use two AA batteries. Generally the device will last for 15-20 hours of continuous use if the infrared illuminator is in the OFF position. If used with the illuminator, expect 30-40% less operating time.

What is the warranty on the FoxBat?
Every Foxbat comes with a one-year limited warranty on parts and labor. This warranty does not cover exposure of the device to excessive light which is discussed in more detail in your owners manual.  

MAGNIFIERS

What are the advantages of glass magnifying lenses?
Glass magnifiers allow very high light transmission, which provides a very clear, precise image. Glass magnifiers are also durable and extremely difficult to scratch.

What are the advantages of acrylic magnifying lenses?
Acrylic magnifiers are extremely lightweight and durable. They are shatterproof and difficult to break. Acrylic material also makes it possible to have a smaller, more powerful magnifier inset in the larger lens.

What is the best type of acrylic used to create magnifying lenses?
The highest quality acrylic lenses are made with PMMA (Polymethyl Methacrylate). This material allows for high light transmission, and is very hard and scratch resistant. Almost all of our magnifiers are created using this material.