A video surveillance system has to be functional 24 hours a day in order to aid in the prevention of crime and the perpetrators prosecution. While designing a security system, it is important to consider lighting conditions as a factor that significantly affects camera image quality. Poor lighting conditions can compromise an entire system. Adding AXTON white or infrared (IR) security lighting will increase the effectiveness of your camera in adverse lighting conditions.
While visible or white light is easy to understand, IR light is a concept that is hard to grasp by many. IR light behaves and functions the same as white light, without being visible to the human eye. This is THE ONLY DIFFERENCE. Therefore, for site layout/design purposes it should be treated the same as white or visible light. The amount of visible light around us, also known as ambient light, is measured in lux (e.g., 0.05 lux or 0.1 lux). Because IR light is not in the visible light spectrum, it cannot be measured in lux. The most common way to measure IR light is in watts/M² or Ft². It tells us the IR energy saturation produced by an IR light source over a specific area.
Most camera manufacturers do not test or specify camera sensitivity to IR light. They only define the minimum amount of VISIBLE LIGHT in lux necessary for adequate camera performance. Day/night security cameras typically have a minimum visible light rating ranging from 0.1 lux (a crescent moon on a starry night) to 0.001 lux (an overcast night in a very remote location). Those numbers are often overly optimistic when it comes to providing a dependable/usable image in such low light conditions. Oftentimes these numbers are confused with, or incorrectly interpreted as, sensitivity to IR light. IR light can only be measured in watts/M² or Ft². From manufacturers’ data it is impossible to tell how well an IR illuminator will work with a particular camera without actual lab or field testing. At Axton we have worked very hard to build ongoing relationships with most of the major security camera manufacturers. This has given us the ability to test our products in varying types of lighting and weather conditions.
Below are some commonly asked questions and answers. Also please feel free to contact our tech support via e-mail at firstname.lastname@example.org or call 801/519-0500.
Only the true Day/Night cameras using a physically removable IR cut filter perform well with IR illuminators.
There is a very simple rule: NO LIGHT = NO IMAGE. Even the most advanced and sophisticated Day/Night cameras WILL NOT function in pitch dark or even in very dark conditions. An IR illuminator or white light is required to aid the camera to produce images usable for security purposes.
Performance range for all AXTON lights is specified in the product datasheets. We are very conservative in our numbers. For testing we use mid-range “true Day/Night 1/3” CMOS-based Cameras with physically removable, not digital, IR cut filters that are most widely used for security applications. If you’re using a TRUE Day/Night camera from a REPUTABLE manufacturer with a physically removable IR cut filter, you will get the same or even better results.
The performance of the entire system depends on all of its components, including the camera, the lens, the IR reflectivity of the object and the IR illuminator. To get the most performance out of your system in lowlight follow these simple tips:
- Use true Day/Night cameras with a physically removable IR cut filter.
- Use an IR or White Light illuminator with adequate output power.
- Make sure your camera is equipped with an IR corrected lens. It solves the problem of focus-shift between night and daylight, which causes a blurry picture.
- Match the angle of the IR illuminator to the camera’s field of view.
To increase the lowlight performance and range of a true day/night camera used with an IR light you need to evaluate each system component and how they complement each other. The lens is a very important component as is the output power of the IR illuminator. If you need long-range performance, increasing the IR output power alone will not be sufficient; an appropriate lens will have to be used and vice-versa. Also, keep in mind that light output power verses range is governed by the “inverse square law”. The law simply states; to double the range, the output power must be increased four times. If you want the range to triple, output power needs to be boosted nine times. It’s important to note that higher megapixel cameras require more light.
The IR corrected lens eliminates the focus shift which causes the image to be out of focus and blurry when used with IR illumination. The blur occurs because white light has different focal point than IR light does. The IR corrected lens optimizes system performance under all lighting conditions (day-time and night-time w/IR) and delivers the best possible image quality, especially when used with IR illuminator.
When selecting an IR illuminator make sure its illumination angle matches the camera’s lens field of view (FOV) IR illuminators with the same output power but different illumination angles WILL have different effective ranges. As a rule of thumb, the narrower the illumination angle is, the greater the range; wider illumination angles make the effective range of the IR illuminator shorter.
The built-in automatic Day/Night switch is operated by a sensor or photocell, which automatically turns the IR illuminator or white light ON in low light (Night) and turns it OFF in daytime.
IR and White light illuminators with a built-in automatic Day/Night Switch function perfectly well in simple one or two camera installations. In larger projects however, there may be problems synchronizing the lights with cameras. The Day/Night Switch will either turn the light ON before or after the camera switches to night mode. It is almost impossible to adjust the photocell threshold manually to match the camera. As a result, there may be “blind spots” or lapses in surveillance when the camera switches to night-mode without the IR illuminator because they are not in sync. This can be avoided by synchronizing the camera and the illuminator via the Input/Output (I/O) ports on the illuminator and the camera. As soon as the camera switches to night mode, it sends a signal through the I/O port and turns it on immediately. This works 100% of the time, no matter how many cameras or what types of cameras you have on site.
Ambient (visible) light has a great impact on the IR illuminators ability to aid the performance of a day/night camera. The visible light at the scene dilutes the IR light produced by the illuminator, making it less dense, which impacts its range and camera performance. It is similar to using a conventional flashlight during the day — even though it’s ON, there’s no real difference.
The 850nm wavelength is standard for most security and other applications where a camera requires additional lighting. The 850nm light produces a very faint red glow at its source, but otherwise it is not visible to the naked eye. Most of the true Day/Night cameras with removable IR cut filters have great sensitivity to 850nm wavelength IR, that’s why they are so widely used for IR illumination. Overall the 850nm has an excellent range vs. visibility ratio hence it is ideal for most security and camera lighting applications. The main advantage of the 940nm wavelength is that, in most cases, it is completely invisible to the human eye. This is an imperative for law enforcement and military applications where covert operation is essential to mission success and safety. Traffic and railroad applications also benefit from 940nm wavelength because the red glow can be falsely interpreted as a signal. Only a handful of cameras are sensitive to 940nm wavelength and the range is about 40-50% shorter than 850nm is. We recommend when selecting a 940nm IR illuminator to be sure that your application really needs it and that your camera is capable of recognizing it.
All of AXTON’s IR or white light illuminators have extended low-voltage or PoE/PoE+ power inputs. If the location has low-voltage or PoE available there is no need for an additional power source. We offer outdoor rated power converters if you only have access to 110V-240V power. Some of our larger systems already come with a 110V-240V to low voltage power converter option for providing the unit with the required power.
The Pan/Tilt U-bracket is included with all lights that we sell except for Nano Series lights which also come with custom mounting brackets and Omni Series indoor lights which require no mounting bracket. We also have additional brackets that are designed to fit with the Pan/Tilt U bracket in various mounting configurations. See the brackets section of our website for more information.