Though Night Visions Devices (NVD's) are very easy to use, technical jargon makes their literature tricky to understand. While any night vision equipment will greatly improve your ability to see at night, there are different grades of night vision goggles, night vision scopes, and thermal imaging cameras - from simple Gen 1 Night Vision monocular to an advanced Generation 3 Military Night vision goggles and rifle scopes - that will give you different levels of performance. While various digital night vision systems and thermal imaging cameras are becoming more available, the information about Night Vision presented below mostly focuses on how the most common night vision technology works - NV devices with various types of image intensifiers that convert weak light from the visible and near-infrared spectrum to visible light detectible by a human eye.
How Night Vision Devices work
Night Vision Scopes are sophisticated optico-electronic devices that assist viewing in near or complete darkness by amplifying all available light. Unlike telescopes and binoculars, night vision is usually not intended for magnification of remote objects (most night vision devices offer either no magnification 1x to very low 2x to 4x magnification).
Most night vision devices offered by OpticsPlanet.com include a built-in Infra Red (IR) Illuminator that acts as a "night vision flashlight" and provides additional light, making viewing in complete darkness a reality. A small red dot appears on the front of the night vision device when the IR Illuminator is ON. There are now Night Vision Blackout Infrared IR Filter Kits for Military Vehicles and even regular Spot Light Flashlights.
When using a night vision scope, you are actually looking at an image that is projected by the intensifier tube located inside the unit. Light enters the night vision device through the objective lens and hits the photocathode in front of the intensifier tube. High-energy electrons produced by the photocathode create an image on the phosphor screen on the back of the tube. This brighter image is projected through the eyepiece to the user?s eye. The amount of light gain (15.000 to 40,000 times) produced by the tube determines the brightness and clarity of the viewed image.
CHOOSING A NIGHT VISION DEVICE
The most common question in regards to night vision selection is "What is the difference between night vision generations?" All Night Vision products amplify existing light, allowing you to see in dark conditions too dark for the naked eye. Night Vision goggles, monoculars and binoculars collect and amplify existing light through the objective lens, which is then focused on the image intensifier. Inside the intensifier, a photocathode is "excited" by the light and converts the photon energy into electrons. These electrons accelerate across an electrostatic field inside the intensifier and strike a phosphor screen (like a green monochrome TV screen) which emits an image that you can see. It is the acceleration of electrons, which provides gain and enhances the image. The key difference between the night vision generations is the intensifier technology. Gen. I Night Vision devices use an intensifier tube that amplifies ambient light by accelerating electrons and striking a phosphor surface just like a Television. Generation II night vision devices add a micro-channel plate that multiplies the number of electrons before they impinge on the phosphor screen, thus increasing gain; Generation III Night Vision goggles, monoculars and scopes further add a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen II night vision devices. Generation 4 Night Vision is now offered by ATN. Generation II and III night vision devices offer greater light amplification, they are definitely better than Generation I, but a price beyond the reach of most buyers. Modern Generation I Night Vision devices are high quality and provide light amplification adequate for most recreational activities camping, hiking, fishing, boating, and nature viewing, and for many professional uses such as surveillance, search and rescue, and property management.
General viewing distance with a 1x magnification Night Vision device
There are many different variables that can effect 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.
What Night Vision to buy?
When you are looking for night vision goggles or binoculars, choose the optical lens package, unit size and price that suits you best, and for most recreational use you normally do not worry about the slight differences in technical specifications. So many variables affect seeing in the dark. Some environments just soak up the light, particularly trees and dense vegetation. It is not possible to give exact, reliable performance specifications that will fit real life conditions. We can only list the technical capabilities. If you want to read up on technical details and see more details on technical details of image intensifier tubes used in night vision devices, please read our "HOW STARLIGHT TECHNOLOGY WORKS" article provided by ATN Night Vision (ATNcorp.com).
Refer to the GLOSSARY for definitions of terms.
THE GREAT NVD DEBATE
OpticsPlanet.com offers night vision products from all major night vision manufacturers - ATN Night Vision, Bushnell Night Vision, ITT Night Vision, Morovision Night Vision, Night Detective NV, Night Owl Night Vision, US Night Vision, Yukon Night Vision, and Zeiss Night Vision. The models we have selected for our store are the best in their price range and offer great features.
Info on Night Vision Devices.
Q: What is a Night Vision Device (NVD)?
A: Night Vision Devices are electronically enhanced optical devices that enable us to see in near-total darkness.
Q: What is the minimal amount of light required to operate an NVD?
A: The threshold of vision with an NVD can vary with different generations, the quality of the devices, distance and the environment. A Generation-1 Night vision with 500x amplification will give a very useful image in the dimmest light of a scarcely visible new moon. From 100 feet, you can distinguish between kinds of animals, whether a human figure is familiar, male or female. While the screen images are not as sharp as a photograph, night vision devices are astonishing in what they accomplish. System amplification of most second-generation night vision devices is around 22,000 times!
Q: Why use a night vision device instead of a flashlight?
A: Two Reasons:
- Night Vision 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 vision sensitivity than many nocturnal animals.
- 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.
Q: What can I see with night vision?
A: Even on a moonless night or in a dark interior, everything within range of the IR illuminator.
Q: Do you need a license to use night vision?
A: No license is required, but they are valuable to security and rescue occupations such as police, fire, private investigators, security guards, harbor patrols etc. Firemen can find trapped victims in dark buildings.
Q: How does night vision work?
A: Night vision optics are similar to video cameras. Instead of focusing the image on the film plane or CCD (video chip), the objective lens focuses the image on one end of a light intensifier tube. There it is turned into electrons, amplified, and accelerated past a field-forming electrode to a phosphor-covered screen where the image is inverted and focused by static electricity. The phosphors glow brightly where struck by electrons, the same principle by which fluorescent lights brighten a room. The observer looks at the screen through an optical eyepiece or eyepieces and sees the image.
Q: Is light required to make a NVD operate?
A: Yes, if there is no light to amplify, there can be no image. A night vision device cannot work in total darkness, but many have a built-in light source to project a small amount of virtually invisible infrared light onto the subject.
Q: Are night vision devices sold by OpticsPlanet.com dangerous?
A: Take care not to aim the near-infrared, low-energy laser illuminator directly at the eye. These low-energy emitters operate at wavelengths nearly identical to television remotes. The phosphor screen and internal electron beam are harmless. Conclusion: Night Vision Devices sold by OpticsPlanet.com are safe for sensible adults.
Q: What is the viewing range of night vision?
A: This varies with the model and viewing conditions. The first generation models from OpticsPlanet.com? are useful from less than 5? to more than 200?, depending on conditions and specific optics.
Q: Do all night vision devices have IR Illuminators?
A: Most models sold by OpticsPlanet.com have built-in IR illuminators, and some accept supplementary IR illuminators to increase brightness and range.
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 night vision in daylight?
A: While there are a few Day/Night Rifle scopes available, most NVDs do their job with the help of extremely light sensitive components. They will suffer damage or lose useful life by use in daylight or when overloaded by flashlights, headlights, and brilliant street lights. These light sources can damage the light intensifier tube and phosphor screen even when the units include protective circuitry.
Q: Are night vision 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, then focus the lens on the subject. This simple adjustment takes about five seconds.
Q: Can an 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 NVDs to even 100 hours of use in a year. One danger of purchasing a used night vision 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 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: Is night vision trouble-prone?
A: Night vision devices are less trouble than most cameras.
Q: What if I drop my NVD?
A: You will probably break it! Light intensifier tubes and phosphor screens are delicate.
Q: Can I use night vision in the rain?
A: Night air conditions frequently include fog and high humidity. NVDs can sustain damage from constant humidity or immersion. Avoid getting them wet, wipe them off with a soft dry towel after use, and store them in dry place without temperature extremes.
Q: Is the night vision image as sharp as a camera image?
A: No, the image the user sees is on a glowing phosphor screen, but even "0" generation units introduced during the Korean War can give very useful resolution. OpticsPlanet.com offers seven first- generation models and one second-generation model. All first-generation units produce very recognizable facial features and detail superior to units used by the U.S. Armed Forces in the Vietnam War. Second-generation units improve resolution by about 20% over first-generation units.
Q: What can second-generation night vision do that first generation NVD's Cannot?
A: They have about 45x more light amplification and, as stated above, they produce about 20% better resolution. The great price difference between the two generations is hard for most consumers to justify, but it is a result of the addition of a porous, coated glass screen called a microchannel plate. Under most circumstance, there is little practical difference in results between second-generation and first-generation units of equal quality.
Q: What About Third Generation - and Fourth-Generation NVDs?
A: They are expensive. The Gallium Arsenide semiconductor material used in third-generation photocathodes and microchannel plates is very costly. Serve in a commando unit of the U.S. Armed Forces and you can earn while you use them.
Q: Can I see in Color With my NVD?
A: No, all night vision is monochromatic. The phosphor screen glows with a green color to take advantage of the human eyes heightened sensitivity to green.
Q: What is a Binocular NVD, and why would I want one?
A: There is confusing terminology in the use of the term binocular. Night vision goggles provide dual oculars that fit over both eyes. Dual oculars are more comfortable to use, but in most goggles with one night vision tube you are still viewing an image captured by a single objective on a single screen.
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 NVDs within reach. All Night Vision Devices offered by OpticsPlanet are 100% tested for a wide range of performance standards, including screen spots. Any screens outside of tolerance are scrapped. We at OpticsPlanet.com do offer the best brand name night vision goggles and scopes available on the market today!
Please feel free to contacts us if you have any other questions! You can buy Night Vision goggles, monoculars and binoculars in our store!