Basic knowledge of low-light night vision devices
Shaanxi Ireeda Protective Technology Co., Ltd.
Engineer Manager : Ms.Melin
WhatsApp: +8618291418396
E-mail: melin@ireeda.com
Whether you're a professional or a beginner, whether you're looking for night vision monoculars, night vision goggles, night vision binoculars, or advanced day and night vision systems, you'll find the best options. All night vision equipment descriptions and specifications include many specialized night vision terms. Here, Ireeda , as a professional night vision device developer and manufacturer, will explain the descriptions of the most commonly used terms.
Optical equipment terminology
- Magnification – simply the degree to which an object is magnified. For example, using 7×35 binoculars, the object appears seven times closer than an object without binoculars. The number immediately following the "×" is the diameter (in millimeters) of the objective lens (front). Therefore, using a 50mm objective lens will magnify a 10×50 pair of binoculars by 10 times.
- Field of view (FOV) - The field of view is the width of the area you see at 1,000 yards, measured in degrees or feet.
- Bright light source or strong light protection – an electronic circuit that shuts off or cuts off the power to the night vision device when exposed to strong light (such as car headlights). This protects the image intensifier and extends its lifespan. The device will deactivate and resume normal operation within 1-2 minutes.
- EyePiece Focus - Used to match your night vision range or binocular vision to a specific field of vision.
- Image intensifier or intensifier tube - an active component in a night vision system that amplifies light and displays the available image. Infrared (IR) illuminator - provides an amplified light source to the system, producing an enhanced image in very low light conditions (such as a cave where there is no ambient light to amplify).
- Objective lens– gathers all available light and focuses it onto the image intensifier. It also provides image magnification.
- Phosphorescent screen – Located on the back of the intensifier tube, the green phosphorescent screen displays a visible nighttime image. The human eye is most sensitive to green contrast. Photocathode – Light is converted (photon energy) into electrons (electrical energy), which are then amplified. The objective lens focuses the available light onto the photocathode's photoelectric surface, where the light is excited and passes through the electron tube as electrons.
- Resolution – a measure of the ability to render and display detailed images. Image intensifier resolution remains constant and is expressed as the maximum number of line pairs per millimeter (LP/MM) that can be recognized when a black-and-white striped pattern is focused on a photocathode.
- Exit pupil – The exit pupil is the size of the axis through which light travels into the eye. The more light, the better the contrast. In practice, you can see the exit pupil by holding the eyepiece of your binoculars about 12 inches from your eye. It is the bright ring in the center of the eyepiece. The exit pupil is expressed in millimeters and is usually calculated by dividing the optical power by the objective lens diameter. A 7×35 binocular has an exit pupil of 5 millimeters.
- Prism systems – the left and right tubes of binoculars are connected by an axis. The two most common prism systems are porro and roof. Porro Prism binoculars are characterized by an eyepiece offset from the objective lens. Roof Prism binoculars have lenses arranged in a straight line, resulting in a more compact design.
- Coated optics – The optical glass surface is coated with magnesium fluoride to reduce light loss and glare caused by reflections. Most binoculars are fully multi-coated to further enhance the field of view and reduce eye strain. Some binoculars feature special image-enhancing, amber, high-contrast coatings.
- Waterproof – describes the binoculars' ability to remain completely dry inside when exposed to moisture or fully submerged in water. The binoculars are sealed with O-rings and filled with 100% dry nitrogen, also resisting all forms of moisture.
- Stray light – When light entering binoculars is reflected from the inner surface, the reflected light eventually exits as stray light inside the binoculars. This unfocused light typically degrades the image quality of the scope.
- Focusing Range - All binoculars have infinity focusing capability. Therefore, the main difference between binocular models is the minimum focusing range. Bird enthusiasts tend to prefer models with a polarizing range of approximately 15 feet, but 20 to 25 feet is generally acceptable.
The range of sights you choose will significantly impact how well it works under certain conditions. For example, someone who only wants to use their scope at a rifle range can often drive up and easily set up their gear, including a prism scope with a large objective lens. Target shooters can easily use an 80mm porro prism scope on a full-length tripod without worrying about compactness or lightness, as their car is several yards away. On the other hand, someone planning a moose hunt might be very concerned about weight and the ability to pack the scope in a backpack. Typically, roof prism scopes offer a more compact and lightweight design for hunters or backpackers, making them packable and portable for long distances. While some porro prism scopes are very compact, others offer a wider field of view and resolution, but may not be practical to pack them in the woods. Other features hunters need to consider are rubber armor to protect the scope from blunt force trauma. Waterproof scopes offer a solution for hunters working in rain and snow. This is not a complete list of all the factors to consider when choosing a sounding scope, but hopefully it provides some insight into some of the more critical ones.
- Magnification – The magnification function of a dot sight allows users to observe objects much closer than they would with the naked eye. Magnification is a function of the oscilloscope's optical system and the eyepiece used.
- Objective lens diameter – The objective lens of a scope is used to collect incident light. A 60mm objective lens will collect more light than a 50mm lens. When more light passes through your eye, you will see a brighter, sharper image. Resolution (the ability to see details) is also a function of objective lens diameter.
- Eye relief – Eye relief refers to the minimum distance between the eyepiece and the eye of a point sight endoscope, still allowing you to see the entire field of view. Hunters and shooters who don't wear glasses can use most scopes and eyepieces without any problems. People who wear glasses are more concerned about eye relief. When a person is wearing a standard point sight eyepiece, their glasses may touch the eyepiece. The need for eye relief is a specific individual requirement. Sometimes, people who wear glasses are more comfortable looking through an observation scope without their glasses.
- Optical lens coatings – Lens coatings play a crucial role in focusing light onto the objective end of the lens (which travels through the fundus to your eye). The lens coating portion is responsible for providing brighter, higher-contrast images.
Contact Ireeda for professional, fast, and accurate solutions, product development, and manufacturing services for low-light night vision devices，contact melin@ireeda.com
Shaanxi Ireeda Protective Technology Co., Ltd.
Engineer Manager : Ms.Melin
WhatsApp: +8618291418396
E-mail: melin@ireeda.com
