NIGHT VISION QUESTIONS and ANSWERS

Q. "Can I use a night vision device in extremely low light, or absolutely no light conditions?"
A. 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 conditions with the use of an infrared illuminator, which can be either built-in or attached to the device. Most models in our product line come with a built-in infrared illuminator. On a few models, the infrared illuminator is available as an option.

Q. "Is the Night Visions Device Image as Sharp as a Camera Image?"
A. No, the image the user sees is on a glowing phosphor screen. All first-generation units produce very recognizable facial features and detail. Second-generation units improve resolution by about 20% over first-generation units.

Q. "What is the effective viewing range of a night vision device?"
A. It varies anywhere from 10 to 400 ft. The maximum viewing distance depends on the conditions of use. Overcast conditions, fog, rain etc. may reduce the effective distance of a night vision viewer. An infrared illuminator will increase your viewing range, especially in enclosed spaces like a warehouse, garage or other enclosed parameters

Q. "What is the Range of the IR Illuminator?"
A. This varies with the model and conditions. The low-energy IR illuminators are effective up to more than 100', and very effective at less than 30'.

Q. "Can I see in Color with my NVD?"
A. No, all Night Vision Devices are monochromatic. The phosphor screen glows with a green color to take advantage of the human eye's heightened sensitivity to green.

Q. "What can I see with a Night Visions Device?"
A. Even on a moonless night or in a dark interior, everything within range of the IR illuminator

Q. "What is the General viewing distance with a Night Vision device?"
A. There are many different variables that can affect the distance that you can see with a Night Vision device. First, what are you trying to see? Are you looking for another boat on the water or are you looking for a rabbit in the woods? The larger the object the easier it is too see. Plus, are you trying to see details (what we call recognition range) or are you just trying to see if something is there or maybe you will just see movement but won't be able to 100% determine who or what it is. This is called detection range. Second. Another variable is lighting conditions. The more ambient light you have (starlight, moonlight, infrared light) the better and further you will be able to see you can always see further on a night where the moon and stars are out then if it is cloudy and overcast. We typically state that you can tell the difference between a male and a female or a dog and a deer at about 75 to 100 yards. However, if you were looking across an open field and there was a half moon out you could see a barn or a house 500 yards away. Remember, that the purpose of a Night Vision Device is to see in the dark not necessarily a long ways like a binocular or spotting scope.

Q. "Why use a Night Visions Devices Instead of a Flashlight?"
A. Two reasons: 1) Night Visions Devices make possible a quality of seeing that is far superior to flashlights. They provide your eyes with a light amplification tool that gives you much more night.  2) See, without being seen. Think of the advantages of seeing without intruding when you are trying to find your way around an unlit campground. Property owners can observe nocturnal criminal activity. Hunters and nature lovers can observe animals without startling them. If you suspect a prowler is nearby, you can spot the "perpetrator" without alarming him and safely call the police vision sensitivity than many nocturnal animals.

Q. "Are Night Visions Devices Complex, or Difficult to Use?"
A. They are easier to operate than a video camera. One difference is that you must first focus your eyepiece on the internal screen, and then focus the lens on the subject. This simple adjustment takes about five seconds.

Q. "How do I generally focus a night vision device?"
A. 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.

Q. "Which Night Vision product would you recommend for a first-time user?"
A. Our Standard Series and Weather-Resistant Series Monoculars are affordable and offer many features. They are an excellent choice for those who need a compact easy to operate device. Recreational uses consist of camping, hiking, fishing, boating, and nature viewing. Other activities include surveillance, search and rescue, and property management.

Q. "Can a night vision device and/or infrared illuminator be harmful to an individual?"
A. Night vision products produced by Night Owl Optics® comply with FDA regulations in terms of safety for an electronic device, similar to other electronic devices such as televisions, and radios. Individuals with sensitive eyes, such as those who experience eye fatigue while watching television may experience the same sort of fatigue if they use their night vision viewer for an extended period of time.

Q. "Can NVD Wear out?"
A. Yes, but it is not easy for the non-professional user to wear one out. The phosphor screens are rated at about 1500-2500 hours. They will darken with constant use just like a fluorescent lamp. Few owners subject their NVD's to even 100 hours of use in a year. One danger of purchasing a used Night Visions Devices is the possibility it may have been applied professionally for more than 1,000 hours, leaving only a fraction of its life for the unlucky new owner

Q. "How Long Will the Batteries Last?"
A. This is a bit like asking "What Time Will the fog Lift?" OpticsPlanet.com^TM rates most first generation units for 8 hours constant use with new batteries. This does not include continual use of the IR illuminators, and it presumes the user knows to turn on the unit to activate the screen, then to turn off the unit to use the "free afterglow."

Q. "I see Black Spots on my Screen, is that Okay?"
A. A few black spots throughout the image area are also inherent characteristics of all night vision technology. These spots will remain constant and should not increase in size or number. Night Vision Intensifier Tube blemishes (aka blems or spots) are common in ALL image intensifier tubes. Night Vision Image tubes are never flawless, and every night vision intensifier tube will have blemishes to some degree. The fewer and smaller the blemishes, the better the quality and therefore the higher the price. Tolerance of a few tiny black spots keeps the price of NVD's within reach.

Q. "What type of light source can be harmful to a night vision device?"
A. Your night vision device is designed to assist your viewing in the dark. It may be harmful and will likely damage the device if you use it during the daytime or whenever there is sufficient light to see the object. Also, keep in mind that strong direct light, such as projectors, car headlamps, strong flashlights and so on, may be harmful to your night vision unit if you direct your device at the source of these intense lights.

Q. "When I am operating my night vision Device, I sometimes hear a buzzing sound. Is it normal?"
A. 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 an imperfection. It is the power supply working to produce an image on your intensifier tube. This is then picked up by the ocular so that you can see what you are looking at.

Glossary of Terms

Aberration: When looking through optical devices, if the image is distorted it is caused by an aberration. I might be due to inferior glad quality, one of the internal glass/mirror pieces out of alignment, or maybe some fogging on the objective lens. Though less expensive models are tempting, higher quality devices are less likely to aberrations.

Alignment: Alignment refers to how well the two barrels of the device works together to provide a clear, high quality viewing experience.

Ambient Light: Ambient light refers to light that can be gathered from the moon, stars, or glow from city lights.

Aperture: The size of the open through which light can enter and is listed in millimeters. It is the second number in 7X50, 10X 25, etc. Larger apertures and lens sizes are better in low light such as at dusk or dawn.
Armor: The shell or casing of the device. If you will be on the move you want a thicker stronger armor to protect the binoculars/monocular. This is not as important if the device will be attached to a tripod.

Aspherical Lens: For a sharp, clear image, this lens has flattened edges.

BaK-4 Glass: Minimize the light scattering and allow a bright, clear viewing with this premium, high density barium crown glass.
Binocular: Two telescopes tied together to allow you to view a magnified image, available in many different strengths and magnifications.

Central Focusing: Enables both pieces of binoculars to be adjusted at the same time by the use of a wheel mounted on the top of the device.

Coating: Various substances put on lenses to help make the image brighter and clearer and reduce reflections.

Compass Binocular: Binoculars that have a compass built in, excellent for hiking, hunting, etc.

Contrast: The difference in the amount of light in the foreground as compared to the background. High contrast provides sharper images.

De-alignment: When the lenses are out of alignment, this decreases the clarity of the image.

Depth of Field: The portion of an image that remains sharp while re-focusing the device.

Digital Camera Binoculars: Binoculars with a digital camera built in, allowing you to take pictures of what you are viewing through the lenses.

Diopter Adjuster: An adjuster, usually on the right lens, to allow one side to be focused separately from the other to compensate for vision differences.

Distortion: Used interchangeably with aberration, this refers to an image being our of focus, distorted. Higher quality binoculars tend to have less distortion issues.

Exit Pupil: When the binocular is held a short distance from the eyes, this is the small amount of light visible in the eyepiece. This size is determined by dividing the lens aperture by the magnification. i.e. A 7X35 binocular has an exit pupil of 5mm.

Eye Relief: The distance away from the eyes to hold the binoculars to use them. Eyeglass wearers will want a larger eye relief.

Field Glass: Binoculars that use a second lens instead of prisms to magnify an image. The strength goes only up to about 5X but these are more sturdy devices.

Field of View (FOV): The area visible through binoculars, usually stated in feet per 1000 yards away. FOV increases as magnification decreases.

Fixed Focus: An optical device that does not allow for manual adjustment to focus.

Focus: The method with which you bring images into sharper, clearer view.

Giant Binoculars: Typically used for astronomy using huge objective lenses of 70mm, 80mm 100mm, or more magnification. These are usually mounted stationary as they are quite heavy.

HD (High-Definition) Glass: High Def Glass provides more true color imaging and greatly reduces distortion.

Image Stabilizers: Feature that allows for self-steadying, for those with shaking/wobbly hands or unsteady surfaces such as a boat.

Infrared Illuminator: A light source used in night vision devices, invisible to animal and human eyes, to allow you to see in total darkness.

Individual Focus: Binoculars that focus each eyepiece separately.

Intensifier: Used in night vision devices to use and amplify visible light.

Lens: One or more pieces of optical glass with surfaces curved to converge or diverge transmitted light rays.

Light Transmission: The amount of light passing through the objective lens to the eye. Better amounts of coating increase light transmission.

Line Pairs per Millimeter (lp/mm): Units used to measure resolution.

Magnification: How many time bigger an object will appear, the first set of numbers of Binoculars, i.e. 7X25, 8X42, etc. This is typically 7X-10X and more.

Monocular: Compact devices for magnifying images that use only one barrel, often as small as a pen or human finger.

Night Vision: Devices use to see in partial or total darkness using ambient light, commonly used for military, aviators, law-enforcement, night hunters, hikers and birders.

Nitrogen-Purged: When the air inside the binocular tubes is replaced with nitrogen to prevent fogging, also prevents mildew and mold inside the tubes.

Objective Lens: Lens closest to the object being viewed, collects available light, focuses it on the image intensifier, and provides image magnification.

Ocular Lens: The lens closest to the viewer's eye.

Opera Glasses: Often pocket-size, decorative binoculars with low magnification and large lenses for theater-goers.

O-Ring Sealed: A special sealant on Binoculars for waterproofing.

Parallax: An illusion that seems to cause a changed position when the view changes from one lens to the other.

Phosphor: A coating that gives off light when interacting with energy. Night vision screens are green phosphor.

Porro Prism: These binoculars have prisms in a double Z shape inside the device. These devices can be bigger than other devices and may need re-calibrating at times.

Prismatic Binoculars: Use internal prisms to magnify an object, as opposed to a second lens. Not ideal for heavy-duty use, these prisms can be broken or fall into de-alignment if roughly handled.

Rangefinder Binoculars: These have a rangefinder built in to calculate the distance between you and the object in focus.

Resolution: The measurement of a device's ability to produce a sharp image.

Roof Prism: Complex prism system that are internally aligned and allows the device to be much more compact and lightweight.

Thermal Imaging: Uses infrared light emitted by all objects, depending on it's temperature which allows it to be seen in total darkness.

Variable Power: Adjustable magnification.

Waterproof: Prevent leakage and damage from fogging, can stand up to some moisture but not designated for marine use.

Wide-Angle Binoculars: Binoculars with a wider field of view, usually more than 65 degrees.