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Dave Wilson:
Optical Devices Shed Light on a Dark Subject.
Superman had heat vision, X-ray vision, telescopic vision and microscopic vision. Today, you can wield a power even Superman didn't have: night vision.
A new group of inexpensive monoculars and binoculars lets you see in the dark. Anybody who boats after the sun goes down should give serious consideration to having a night-vision device on board. They can keep you from running aground and help you see your rigging in foul weather.
The gizmos are idiot simple. You turn them on, look through them and focus them. The images are just like what you see on TV: grainy and green, but with surprising detail. For example, a printed sign can be easily read from about 20 yards away. Most of the night-vision gadgets on the market are hand-held monoculars, meaning you peer through them with one eye, like a sailor's spyglass. Binocular devices also are available, at about twice the price of a monocular, which range from $200 to $500. More expensive still are goggles designed to be worn on the head.
Why not just save some money and use a spotlight? Single source illumination--the sort of light you get from one bulb--makes it harder to see within shadows. And shadows conceal all sorts of hazards, like a barely submerged rock. Night-vision devices let you see within shadows.
Technically, night-vision gizmos amplify light, which means they increase light from the stars and any other light source. Remember that scene in "The Silence of the Lambs" where Agent Starling is trapped in a blacked-out basement? As she desperately struggles to find a crazed killer, he hovers inches away, watching her through light-amplification goggles. That couldn't happen. Night vision won't work in the absence of light.
Many night-vision devices get around that by building in an infrared emitter that floods an area with invisible light. They work fine with infrared light, but you'll lose your ability to be invisible; the infrared emitter glows like Rudolph's nose.
There are three different levels, or "generations," of night-vision equipment. The affordable devices designed for consumers are known as Generation I. Generation II and Generation III also are available in stores, but cost thousands of dollars and are used by the military. Each successive generation provides better images and longer battery life, at a higher cost.
Are these things fun?
The truth is, seeing in the dark is like taking off a day in the middle of the week to go people-watching. The good news is there aren't any crowds. The bad news is there's not a lot to look at.
Bottom line: If Superman couldn't do it, it probably wasn't all that cool to start with.
We tested five Generation I devices from three distributors in various locations and weather conditions. The brand name isn't especially important, because most Generation I gear is made in Russia and relabeled for export. For instance, the Bushnell model 26-2042W waterproof monocular looks identical to the Night Owl Optics NONO3Y, (see pic).
The $300 Bushnell 26-3652, a black, business-like monocular, took top honors. It's got a large, 52-millimeter objective lens combined with 3.6x image magnification. The combination is a great compromise of magnification, clarity and weight. The higher the magnification, the more light you lose, and the dimmer the image becomes. That's why astronomers need huge telescopes; bigger scopes pull in more light, which allows for increased magnification.
The 26-3652 runs on two AA batteries; most of the other devices we tested use exotic lithium batteries designed for cameras.
The device gets low marks for its clumsy battery compartment, which requires a screwdriver to open and close. The external mount on the infrared emitter also was a poor design choice. Every other device we tested has the infrared emitter--used to see in total darkness--integrated within the housing. The 26-3652's emitter plugs into a slot on the side, where it could easily be knocked off.
Resolution was excellent for a hundred yards. Shadows beneath the lifeguard towers on the Santa Monica beach late at night concealed nothing from this device, including two lovers entwined in the sand. And let us never speak of that particular experiment again.
Runner-up is the $300 MB-3 from Newcon Optik. It comes dressed in rain-slicker yellow, apparently the international symbol for "I'm waterproof!" It has a large 56mm objective lens but offers only 2.4x magnification. It runs on two AAA batteries and performed well over long distances. This was the smallest and lightest device we tested, but you pay for that with decreased magnification, which kept it from getting the top spot.
MB-3 from Newcon Optik.
Two of our least favorite monoculars were the $200 Night Owl NONO3Y and the apparently identical $300 Bushnell 26-2042W. The Night Owl claims a 3.1x magnification and a 42mm objective lens. But there was no detectable difference between it and the Bushnell 26-2042W, which only claims 2x magnification with its 42mm objective lens.
Bushnell 26-2042W
Night Owl NONO3Y
Both are waterproof--you can tell because they're yellow--and lightweight. But these devices only would be useful over a fairly small area, maybe 50 yards, tops. Plus, they use those annoying camera batteries. The only detectable difference between the two is in the labeling. Oh, and the Night Owl has a much trimmer, cooler case.
The worst-of-show has the highest price tag, the $700 Bushnell 26-3150 binoculars. They have a 50mm objective lens and 3.1x magnification. That power, combined with the depth perception available with the binocular format should have made these a standout. But they're unacceptable on nearly every level.
Bushnell 26-3150
To start with, they're big and heavy. But worst of all, each eyepiece has to be focused independently. This is not a piece of gear you'd want to use when what you're looking at is moving in and out of focus. Fortunately, the binoculars do have a tripod mount, suggesting that they're designed for viewing sitting still.
The Skinny Bushnell 26-3652 Monocular
* Price: $300
* The good: Big lens and high magnification
* The bad: External IR emitter mount
* Bottom line: Best of breed
*
Newcon MB-3 Monocular
* Price: $300
* The good: Small, light and waterproof
* The bad: Not a lot of magnification
* Bottom line: Gilligan would have killed for these
*
Bushnell 26-2042W Monocular
* Price: $300
* The good: Waterproof
* The bad: Least capable
* Bottom line: Rowboat material
*
Night Owl NONO3Y Monocular
* Price: $200
* The good: Waterproof; good price
* The bad: Stats seem inflated
* Bottom line: Least expensive of the lot
*
Bushnell 26-3150 Binoculars
* Price: $700
* The good: You don't have to go through life with this around your neck.
* The bad: Way overpriced, heavy, hard to focus
* Bottom line: You can do better by joining the Army
===========================================
Night Vision FAQs
From Bushnell's website.
Answers To Your Frequently Asked Questions About Night Vision.
Q. What is Night Vision used for?
A. Recreational uses consist of camping, hiking, fishing, boating, and nature viewing. Other uses include surveillance, search and rescue, and property management.
Q. What is the difference between night vision generations?
A. The key difference between the night vision generations is the intensifier technology. Gen. I devices use an intensifier tube that amplifies ambient light by accelerating electrons and striking a phosphor surface just like a Television. Generation II devices add a micro-channel plate that multiplies the number of electrons before they impinge on the phosphor screen, thus increasing gain; Generation III devices further add a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen. II devices. Generation II and III devices offer greater light amplification but a price beyond the reach of most buyers. Generation I devices are high quality and provide light amplification adequate for most recreational activities and for many professional uses.
Q. How does Night Vision work?
A. Bushnell Night Vision products 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 in to 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.
Q. Aren't all Night Vision products the same?
A. No. Only Bushnell Night Vision comes from a proven Leader and Innovator in the Sports Optics Industry.
Q. What is the effective range of night vision?
A. It varies anywhere from 10-400 feet. The maximum viewing distance depends on the conditions of use. Overcast conditions, fog, rain; etc. may reduce the effective distance of a night vision. An Infrared Illuminator will increase viewing range, especially in enclosed areas like a warehouse, cave, or thick brush.
Q. Why isn't there more magnification in a night vision device?
A. The more you magnify the more light you lose.
Q. Why do you focus both the front (Objective lens) and Eye-piece (Ocular)?
A. The short answer is that you don't see through the night vision device, rather you see the phosphor screen on the back of the tube. The objective lens focuses the image on to the front of the intensifier tube. That image is then converted in to electron energy. It paints that picture on the back of the tube. You need to have a sharp image to start with. Then your eye needs to be focused onto the back of the tube where the image resides. Every eye is different and therefore the ocular focus is very important. Focus the ocular first and then move to the objective lens. You may have to adjust each lens several times before getting a sharp image.
Q. How do I use a Bushnell Night Vision device in extremely low light, or no-light conditions?
A. All night vision devices need some available light to work. It is possible to see a bright image in low light or no light conditions with the use of an Infrared Illuminator. An Infrared Illuminator is standard on all Bushnell Night vision devices.
Q. Since a night vision device is sensitive to Infrared (IR) light, can it detect heat?
A. Night vision devices operate as a light amplifier for light in the "near visible" light range. Generally, this is in the 750-850 nanometer range. It can not detect heat, which is at a much lower end of the light spectrum and requires thermal imaging technology.
Q. What type of light source can be harmful to a night vision device?
A. Night Vision devices are designed for use in the dark. It may be harmful and can damage the device if you use it during the daytime or in other very bright situations. 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. With this said, Bushnell Night Vision devices have electronic protection against such damage. Most of these are simple turn off overload circuits, but some have more sophisticated and separate light sensing mechanisms.
Q. What characteristics might I expect from my Night Vision device?
A. All Bushnell Night Vision Monocular scopes are activated in a way that can not be left on when not in use. The power button is designed to give power only while being depressed.
The binocular devices do have on/off switches that require the user to remember to turn off the unit. Some level of "buzzing" sound is quite normal and is intended to be useful in remembering to turn off these units when done using them.
The image of a night vision device will not be as sharp as that of a daylight binocular. This is due largely to the image being generated on a phosphor screen.
Black spots may be visible in the image. This comes as a natural process of manufacturing the intensifier tubes.
Q. What's inside a night vision scope?
A. A night vision scope is made up of a set of optics (glass), a simple power supply (batteries, wire, transformer, regulators and capacitors) and an image intensifier (a glass vacuum tube with a light sensitive coating at one end and a phosphor screen at the other).
Q. Are Bushnell Night Vision devices safe?
A. Yes. All of Bushnell's Night Vision products include shield-encased image intensifiers to block x-rays. All of Bushnell's infrared illuminators utilize harmless filtered incandescent bulbs or light emitting diodes (LED's) instead of lasers.
Q. How should I care for my Night Vision device?
A. The number one damage factor is using the device in bright light. While all Bushnell Night Vision devices have a cut-off circuit when over exposed, exposure will shorten the life span of a night vision device.
Exposure to rain, fog, or even extremely high humidity may damage night vision devices. Built for use at night, they can withstand short exposure to dampness or high humidity conditions.
Night Vision devices have delicate vacuum intensifier tubes that are sensitive to impact and should be handled carefully.
Clean lenses the same way you would your camera. The lenses are optically coated and may be scratch if abrasive material is used or if dirt is rubbed into the glass. Usually there is no need to remove the lenses and clean inside.
Storage for long periods is best in a cool dry place with the batteries removed.
Q. What is the warranty for Night Vision devices?
A. Bushnell Night Vision products are unquestionably warranted to be free of defects in material and workmanship for one year after the date of purchase. In the event of a defect under this warranty, we will at our option, repair or replace the product.
More info at
http://www.bushnell.com/productinfo/nightv...ightvision.html
Bushnell Night Vision
Night Owl Optics
Optical Devices Shed Light on a Dark Subject.
Superman had heat vision, X-ray vision, telescopic vision and microscopic vision. Today, you can wield a power even Superman didn't have: night vision.
A new group of inexpensive monoculars and binoculars lets you see in the dark. Anybody who boats after the sun goes down should give serious consideration to having a night-vision device on board. They can keep you from running aground and help you see your rigging in foul weather.
The gizmos are idiot simple. You turn them on, look through them and focus them. The images are just like what you see on TV: grainy and green, but with surprising detail. For example, a printed sign can be easily read from about 20 yards away. Most of the night-vision gadgets on the market are hand-held monoculars, meaning you peer through them with one eye, like a sailor's spyglass. Binocular devices also are available, at about twice the price of a monocular, which range from $200 to $500. More expensive still are goggles designed to be worn on the head.
Why not just save some money and use a spotlight? Single source illumination--the sort of light you get from one bulb--makes it harder to see within shadows. And shadows conceal all sorts of hazards, like a barely submerged rock. Night-vision devices let you see within shadows.
Technically, night-vision gizmos amplify light, which means they increase light from the stars and any other light source. Remember that scene in "The Silence of the Lambs" where Agent Starling is trapped in a blacked-out basement? As she desperately struggles to find a crazed killer, he hovers inches away, watching her through light-amplification goggles. That couldn't happen. Night vision won't work in the absence of light.
Many night-vision devices get around that by building in an infrared emitter that floods an area with invisible light. They work fine with infrared light, but you'll lose your ability to be invisible; the infrared emitter glows like Rudolph's nose.
There are three different levels, or "generations," of night-vision equipment. The affordable devices designed for consumers are known as Generation I. Generation II and Generation III also are available in stores, but cost thousands of dollars and are used by the military. Each successive generation provides better images and longer battery life, at a higher cost.
Are these things fun?
The truth is, seeing in the dark is like taking off a day in the middle of the week to go people-watching. The good news is there aren't any crowds. The bad news is there's not a lot to look at.
Bottom line: If Superman couldn't do it, it probably wasn't all that cool to start with.
We tested five Generation I devices from three distributors in various locations and weather conditions. The brand name isn't especially important, because most Generation I gear is made in Russia and relabeled for export. For instance, the Bushnell model 26-2042W waterproof monocular looks identical to the Night Owl Optics NONO3Y, (see pic).
The $300 Bushnell 26-3652, a black, business-like monocular, took top honors. It's got a large, 52-millimeter objective lens combined with 3.6x image magnification. The combination is a great compromise of magnification, clarity and weight. The higher the magnification, the more light you lose, and the dimmer the image becomes. That's why astronomers need huge telescopes; bigger scopes pull in more light, which allows for increased magnification.
The 26-3652 runs on two AA batteries; most of the other devices we tested use exotic lithium batteries designed for cameras.
The device gets low marks for its clumsy battery compartment, which requires a screwdriver to open and close. The external mount on the infrared emitter also was a poor design choice. Every other device we tested has the infrared emitter--used to see in total darkness--integrated within the housing. The 26-3652's emitter plugs into a slot on the side, where it could easily be knocked off.
Resolution was excellent for a hundred yards. Shadows beneath the lifeguard towers on the Santa Monica beach late at night concealed nothing from this device, including two lovers entwined in the sand. And let us never speak of that particular experiment again.
Runner-up is the $300 MB-3 from Newcon Optik. It comes dressed in rain-slicker yellow, apparently the international symbol for "I'm waterproof!" It has a large 56mm objective lens but offers only 2.4x magnification. It runs on two AAA batteries and performed well over long distances. This was the smallest and lightest device we tested, but you pay for that with decreased magnification, which kept it from getting the top spot.
MB-3 from Newcon Optik.
Two of our least favorite monoculars were the $200 Night Owl NONO3Y and the apparently identical $300 Bushnell 26-2042W. The Night Owl claims a 3.1x magnification and a 42mm objective lens. But there was no detectable difference between it and the Bushnell 26-2042W, which only claims 2x magnification with its 42mm objective lens.
Bushnell 26-2042W
Night Owl NONO3Y
Both are waterproof--you can tell because they're yellow--and lightweight. But these devices only would be useful over a fairly small area, maybe 50 yards, tops. Plus, they use those annoying camera batteries. The only detectable difference between the two is in the labeling. Oh, and the Night Owl has a much trimmer, cooler case.
The worst-of-show has the highest price tag, the $700 Bushnell 26-3150 binoculars. They have a 50mm objective lens and 3.1x magnification. That power, combined with the depth perception available with the binocular format should have made these a standout. But they're unacceptable on nearly every level.
Bushnell 26-3150
To start with, they're big and heavy. But worst of all, each eyepiece has to be focused independently. This is not a piece of gear you'd want to use when what you're looking at is moving in and out of focus. Fortunately, the binoculars do have a tripod mount, suggesting that they're designed for viewing sitting still.
The Skinny Bushnell 26-3652 Monocular
* Price: $300
* The good: Big lens and high magnification
* The bad: External IR emitter mount
* Bottom line: Best of breed
*
Newcon MB-3 Monocular
* Price: $300
* The good: Small, light and waterproof
* The bad: Not a lot of magnification
* Bottom line: Gilligan would have killed for these
*
Bushnell 26-2042W Monocular
* Price: $300
* The good: Waterproof
* The bad: Least capable
* Bottom line: Rowboat material
*
Night Owl NONO3Y Monocular
* Price: $200
* The good: Waterproof; good price
* The bad: Stats seem inflated
* Bottom line: Least expensive of the lot
*
Bushnell 26-3150 Binoculars
* Price: $700
* The good: You don't have to go through life with this around your neck.
* The bad: Way overpriced, heavy, hard to focus
* Bottom line: You can do better by joining the Army
===========================================
Night Vision FAQs
From Bushnell's website.
Answers To Your Frequently Asked Questions About Night Vision.
Q. What is Night Vision used for?
A. Recreational uses consist of camping, hiking, fishing, boating, and nature viewing. Other uses include surveillance, search and rescue, and property management.
Q. What is the difference between night vision generations?
A. The key difference between the night vision generations is the intensifier technology. Gen. I devices use an intensifier tube that amplifies ambient light by accelerating electrons and striking a phosphor surface just like a Television. Generation II devices add a micro-channel plate that multiplies the number of electrons before they impinge on the phosphor screen, thus increasing gain; Generation III devices further add a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen. II devices. Generation II and III devices offer greater light amplification but a price beyond the reach of most buyers. Generation I devices are high quality and provide light amplification adequate for most recreational activities and for many professional uses.
Q. How does Night Vision work?
A. Bushnell Night Vision products 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 in to 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.
Q. Aren't all Night Vision products the same?
A. No. Only Bushnell Night Vision comes from a proven Leader and Innovator in the Sports Optics Industry.
Q. What is the effective range of night vision?
A. It varies anywhere from 10-400 feet. The maximum viewing distance depends on the conditions of use. Overcast conditions, fog, rain; etc. may reduce the effective distance of a night vision. An Infrared Illuminator will increase viewing range, especially in enclosed areas like a warehouse, cave, or thick brush.
Q. Why isn't there more magnification in a night vision device?
A. The more you magnify the more light you lose.
Q. Why do you focus both the front (Objective lens) and Eye-piece (Ocular)?
A. The short answer is that you don't see through the night vision device, rather you see the phosphor screen on the back of the tube. The objective lens focuses the image on to the front of the intensifier tube. That image is then converted in to electron energy. It paints that picture on the back of the tube. You need to have a sharp image to start with. Then your eye needs to be focused onto the back of the tube where the image resides. Every eye is different and therefore the ocular focus is very important. Focus the ocular first and then move to the objective lens. You may have to adjust each lens several times before getting a sharp image.
Q. How do I use a Bushnell Night Vision device in extremely low light, or no-light conditions?
A. All night vision devices need some available light to work. It is possible to see a bright image in low light or no light conditions with the use of an Infrared Illuminator. An Infrared Illuminator is standard on all Bushnell Night vision devices.
Q. Since a night vision device is sensitive to Infrared (IR) light, can it detect heat?
A. Night vision devices operate as a light amplifier for light in the "near visible" light range. Generally, this is in the 750-850 nanometer range. It can not detect heat, which is at a much lower end of the light spectrum and requires thermal imaging technology.
Q. What type of light source can be harmful to a night vision device?
A. Night Vision devices are designed for use in the dark. It may be harmful and can damage the device if you use it during the daytime or in other very bright situations. 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. With this said, Bushnell Night Vision devices have electronic protection against such damage. Most of these are simple turn off overload circuits, but some have more sophisticated and separate light sensing mechanisms.
Q. What characteristics might I expect from my Night Vision device?
A. All Bushnell Night Vision Monocular scopes are activated in a way that can not be left on when not in use. The power button is designed to give power only while being depressed.
The binocular devices do have on/off switches that require the user to remember to turn off the unit. Some level of "buzzing" sound is quite normal and is intended to be useful in remembering to turn off these units when done using them.
The image of a night vision device will not be as sharp as that of a daylight binocular. This is due largely to the image being generated on a phosphor screen.
Black spots may be visible in the image. This comes as a natural process of manufacturing the intensifier tubes.
Q. What's inside a night vision scope?
A. A night vision scope is made up of a set of optics (glass), a simple power supply (batteries, wire, transformer, regulators and capacitors) and an image intensifier (a glass vacuum tube with a light sensitive coating at one end and a phosphor screen at the other).
Q. Are Bushnell Night Vision devices safe?
A. Yes. All of Bushnell's Night Vision products include shield-encased image intensifiers to block x-rays. All of Bushnell's infrared illuminators utilize harmless filtered incandescent bulbs or light emitting diodes (LED's) instead of lasers.
Q. How should I care for my Night Vision device?
A. The number one damage factor is using the device in bright light. While all Bushnell Night Vision devices have a cut-off circuit when over exposed, exposure will shorten the life span of a night vision device.
Exposure to rain, fog, or even extremely high humidity may damage night vision devices. Built for use at night, they can withstand short exposure to dampness or high humidity conditions.
Night Vision devices have delicate vacuum intensifier tubes that are sensitive to impact and should be handled carefully.
Clean lenses the same way you would your camera. The lenses are optically coated and may be scratch if abrasive material is used or if dirt is rubbed into the glass. Usually there is no need to remove the lenses and clean inside.
Storage for long periods is best in a cool dry place with the batteries removed.
Q. What is the warranty for Night Vision devices?
A. Bushnell Night Vision products are unquestionably warranted to be free of defects in material and workmanship for one year after the date of purchase. In the event of a defect under this warranty, we will at our option, repair or replace the product.
More info at
http://www.bushnell.com/productinfo/nightv...ightvision.html
Bushnell Night Vision
Night Owl Optics
