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Outdooroptics support services

Under normal use, no maintenance is required for many years. If you are a private person and you have a problem with your device, please contact your dealer.
Are you a dealer and do you have problems with a device? After you have logged in as a dealer, you can fill in a repair form (RMA form) and contact our service department.

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The NightSpotter series

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The NightClip series

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The NightScope series

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Glossary and Technical terms

Equivalent backlight (EBI)

This is what you see in a picture tube turned on, but in complete darkness. It is affected by temperature, the warmer the night vision device, the brighter the backlight. The EBI is measured in lumens per square centimeter (lm / cm2), the lower the value, the better. The EBI value determines the lowest light value at which you can see something. Objects below this amount of light are masked by the EBI.


Die Fähigkeit eines Bildverstärkers oder Nachtsichtsystems, zwischen nahe beieinander liegenden Objekten zu unterscheiden. Die Bildverstärkerauflösung wird in Linienpaaren pro Millimeter (lp/mm) gemessen, während die Systemauflösung in Zyklen pro Milliradian gemessen wird. Für ein bestimmtes Nachtsichtsystem bleibt die Bildverstärkerauflösung konstant, während die Systemauflösung durch Änderung der Objektiv- oder Okularoptik durch Hinzufügen von Vergrößerungs- oder Relaislinsen beeinflusst werden kann. Häufig ist die Auflösung im gleichen Nachtsichtgerät sehr unterschiedlich, wenn sie in der Mitte des Bildes und am Umfang des Bildes gemessen wird. Dies ist besonders wichtig für Geräte, die für Fotografie oder Video ausgewählt wurden, bei denen die gesamte Bildauflösung wichtig ist. Gemessen in Linienpaaren pro Millimeter (lp/mm).

Image distortion

This problem is more easily recognized in high light conditions. Image distortions are detected by vertical objects such as trees or poles that appear to wave or bend when the user moves their head vertically or horizontally when looking through the glasses. Ground surfaces in the hovering direction can swell or sink. The distortion does not change during the life of an image intensifier. Limits for permissible distortions are an important part of the performance data, since excessive distortions can impair the viewing of the image and thus the ability of the operator to perform necessary flight maneuvers.


The picture tube output that creates the visible picture. Phosphorus (P) is used on the inside of the screen to create the glow and therefore the image. Depending on the manufacturer and generation of tubes, different phosphors are used in image intensifier tubes.

Image disparity

This condition can exist if there is a difference in brightness between the two image intensifier modules within the same binoculars.


Auto Gating is an electronic solution to maintain visibility even in difficult lighting conditions (car headlights, thunderstorms, muzzle flashes, etc.) and to extend the life of the image intensifier tube. It is a tried and tested means of maintaining the high MTF (Modulation Transfer Function) and resolution that is achieved at full operating voltage. At the same time, the exposure of the image intensifier tube to high illuminance levels is reduced.

Chicken wire

Ein unregelmäßiges Muster aus dunklen Linien im Bildbereich oder in Teilen des Bildbereichs. Unter den schlechteren Bedingungen bilden diese Linien sechseckige oder rechteckige Linien.

Electronic noise

also known as scintillation. A faint, random, sparkling effect across the image area. Scintillation is a normal feature of microchannel image intensifiers and is more pronounced in low light conditions.

Fiber optic inverter

Ein Bündel mikroskopisch kleiner lichtdurchlässiger Fasern, die um 180 Grad gedreht wurden.

Field-of-View (FOV)

The width or solid angle of the outside scene that can be viewed through the side and vertical amplifier tubes. Typical NVGs have a 40 ° FOV value. There are NVGs in development that are trying to significantly increase this FOV to improve pilot performance. An example of a wide FOV NVG would be the Panorama NVG '.

FOM – Figure of Merit

The FOM value is calculated as follows: S / R x lp / mm (S / R = S / N signal - signal-to-noise ratio). The FOM value can currently * for Gen. II, Gen. II +, ECHO, SuperGen®, Gen. III, XD-4 ™ and XR5 ™ values ​​exceed 2000. (PHOTONIS is able to manufacture XR5 ™ tubes with FOM values ​​up to 2340, which is currently an absolute top value. Your purchase is reserved for very few state security institutions). Tubes with very high S / R = S / N and very high resolution (lp / mm) thus have the highest FOM.


Also called brightness enhancement or luminance gain. This is the intensity with which an image intensifier tube amplifies the light input. It is usually measured as a tube gain and system gain. In every night vision system, the tube gain is reduced by the lenses of the system and is influenced by the quality of the optics or a filter; therefore, system gain is a more important measurement for the user.

Gallium arsenide (GaAs)

The semiconductor material used in the manufacture of the Gen III photocathode.

Generations of image intensifiers

Image intensifier tubes are classified according to GEN numbers assigned by the US Army's Night Vision Laboratory. Each GEN denotes a new contract or manufacturing process.
Note: Generations do not define the performance data of the image intensifier.

  • Generation I
    It started with electrostatically focused Generation I tubes with high image resolution, wide dynamic range and low noise.
  • Generation II
    Introduction of the microchannel plate for a much higher gain in the 1980s. The original image resolution was lower than that of the first generation amplifiers, but the gain was much higher.
  • Generation III
    In the late 1980s, an image intensifier with a GaAs photocathode was developed, which has an increased sensitivity in the near infrared range. In the late 1990s, Gen III tubes came to the market with greatly improved performance. These types are known as Gen III Omni III and Gen III Omni IV.

In 1996, PHOTONIS introduced the new European standard for low-light imaging. This new performance family offers superior performance that exceeds the performance of GEN III image intensifiers.

Bright spots

These are signal-induced errors in the image area, which are caused by an error in the film on the MCP. A bright spot is a small, uneven, bright area that can flicker or appear constant. Bright spots usually go away when the light is hidden. Not all light spots make ANVIS unusable. A test can be done as follows: Place a cupped hand over the lens to block out all light. Make sure that no bright spot is just a bright area in the scene being viewed. If the bright spot remains, there is an emission point that must be checked.

Brightness enhancement

The brightness gain is determined by the ratio of the output brightness in units of lm / cm2.


See Fixed Pattern Noise.


This is the process of moving light rays in parallel lines. The process of aligning the various internal optical axes of a system with one another is also called this.


Is the unit of light flow that is perceived by the human eye in a second.

Line pairs per millimeter (lp / mm)

Units for measuring the image intensifier resolution. Usually determined from a 1951 Air Force Resolving Power Test target. The goal is a series of patterns of different sizes, consisting of three horizontal and three vertical lines. The lines and the distance between the lines in each of the different patterns differ in width; the narrower the width, the greater the resolution needed to distinguish the lines in a particular pattern. Human subjects must be able to clearly distinguish all horizontal and vertical lines of a particular pattern so that an image intensifier can achieve the resolution represented by that pattern.

Light sensitivity (photoresponse)

Also called photocathode sensitivity or photoresponse. The ability of the photocathode material to produce an electrical response when exposed to light waves (photons). Usually measured in microamps of the current per lumen (mA / lm).


Moving an observer's eyes inward from parallel to view a nearby object.

Microchannel plate (MCP)

A metal-coated glass pane that multiplies the electrons generated by the photocathode. PHOTONIS SAS produces MCP's with 11 million pores and is constantly developing and improving the MCP's performance for improved image intensifier tube performance. Electrons entering the channel hit a wall and knock out additional electrons, which knock more electrons, creating a cascading effect. MCPs eliminate the distortion characteristics of GEN I systems. The number of holes in an MCP is an important factor in determining the resolution.

Microamps per lumen

The measure of the electrical current (A) generated by a photocathode when exposed to a measured amount of light (lumens).


The illuminance is measured in lux. it is the illuminance that is generated on an area of ​​one square meter from a uniform point source with an intensity of one lumen per square meter.


The shortest wavelengths in the infrared, typically 750 to 2,500 nanometers (nm). GEN II works from about 440 to 950 nanometers.


Military specification term. These are the minimum acceptable requirements for products procured by the U.S. Department of Defense. The use of the term MILSPEC means that the product complies with the applicable military specifications.

Photoresponse (PR)

See photosensitivity.


The input surface of an image intensifier, which absorbs light energy and in turn emits electrical energy in the form of an electron image. The type of material used is a key feature of generations of image intensifiers.

Phosphor screen

The phosphor screen converts electrons into photons. A very thin layer of phosphor is applied to the output light guide system and emits light when it is hit by electrons. See also photocathode.

System reinforcement

Corresponds to the tube gain minus the losses caused by system components such as lenses, beam splitters and filters.

Signal-to-noise ratio (SNR)

A measure of the light signal that reaches the eye divided by the perceived noise from the eye's perspective. The SNR of a tube determines the low light resolution of the picture tube; So the higher the SNR, the better the ability of the tube to resolve objects with good contrast in low light conditions. Since SNR is directly related to the sensitivity of the photocathode and also takes into account the phosphor efficiency and the MCP operating voltage, it is the best single indicator for the performance of an image intensifier.

Black spots

Black spots are cosmetic defects or dust particles between the lenses and arise during production. They do not affect the performance or the reliability of the device.


The magnification power of the lens. Quadruple performance (4x) means that the image appears four times larger than when viewed with a 1x lens.


Three types of distortion are most relevant to night vision devices: geometric distortion, S distortion, and sheer distortion.
  • Geometric distortion - is inherent in all Gen 0 (infrared tubes, e.g. B-20) and Gen I and in some Gen II image intensifier tubes that use electrostatic rather than fiber optic image inversions. Geometric distortion is eliminated in picture tubes that use a microchannel plate and glass fiber for image inversion, but there may be some S-distortion in these tubes.
  • S-distortion - results from the twisting process in the manufacture of fiber-optic inserting machines). Usually the S-distortion is very low and difficult to see with the naked eye.
  • Sheer distortion - can occur in any picture tube that uses fiber optic bundles for the phosphor screen. It appears as a cutout or offset in a straight line, which is viewed in the image area because the line was sheared.

Different initial brightness

This condition is evidenced by areas of different brightness in or over the image area. The lower contrasts have no pronounced demarcation lines and do not impair the image quality. This condition should not be confused with shading.

Blendschutz / Bright Source Protection (BSP)

An electronic function that reduces the voltage to the photocathode when the night vision device is exposed to bright light sources such as daylight or vehicle lighting. The BSP protects the picture tube from damage and extends its lifespan. However, BSP can cause resolution to decrease if it works.


Also known as electronic noise. A faint, random, sparkling effect across the image area. Scintillation is a normal feature of microchannel image intensifiers and is more pronounced in low light conditions.


Do you have a question about your image intensifier? Here are our most asked questions. For more specific questions you can contact our service departement or your local dealer.

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