Surveillance and Security Camera Buyer's Guide
Although the way security cameras are used hasn't changed that much over the years there have been significant advances in the technology used in cameras. Today's cameras are, cheaper, smaller, and better than ever and the recording equipment is far more sophisticated and rich in features.
We want to make the sometimes confusing search for CCTV monitoring and recording systems easier for you. This guide is written to help you select the best and most economical type of video surveillance equipment for your application. It will also help you learn more about cameras, lenses, Digital Video Recorders (DVR), cabling, power supplies, and related accessories. If you have any questions as you read this guide, please do not hesitate to call our expert staff at 866-424-9070 for advice.
Wired VS Wireless
Wired security cameras are the optimal choice, as they provide the best video quality, zero interference, and are cost effective. They can be installed hundreds of feet away from the security DVR system. Figure 1.1 shows a typical connectivity diagram.
With wired security cameras you do not have to power the camera locally. Siamese cable provides video and power in the same cable, so you can connect your cameras to the DVR and power them remotely. We have a comprehensive inventory of wired security cameras. We also offer Siamese cable pre-cut to commonly used lengths and on a spool. For runs longer than 700 Ft., we recommend using CAT5e cable and Balun connectors. Using this method, the video signal can be transmitted up to about 1,300 Ft.
We can refer you to professional installers in your area; however, using our step-by-step installation guide, the layperson can easily and quickly install our video surveillance products.
Wireless cameras are relatively expensive and are not as reliable as wired systems. Most wireless systems are Line of Sight (LOS). Remember that wireless security cameras require power to operate. So Wireless cameras are relatively expensive and are not as reliable as wired systems. Most wireless systems are Line of Sight (LOS). Remember that wireless security cameras require power to operate. So even though by going with a wireless solution you can eliminate the need for coaxial cable for video transmission, you still have to wire the camera to a power source.
Cameras & Lenses
There are many security camerasomplementary Metal Oxide Semiconductor) or CCD (Charge Couple Device) chips. The size of the chip is normally 1/4", 1/3" or 1/2". As a rule of thumb, the larger the chip size, the higher the quality of the image produced and the higher the price. However, with advances in technology, higher density 1/4" and 1/3" CCD chips can now produce as high an image quality as many older 1/3" or 1/2" chips. The most popular size is 1/3" and you don't see many cameras with 1/2" anymore.
Some of the more popular security camera types are dome cameras which are aesthetically more pleasing. They blend into your surroundings especially with drop down ceilings and are great for use in stores, lobbies and other public places. Infrared cameras have become very popular in recent years for their ability to film in total darkness by the use of IR illuminators.
Traditional CCTV security cameras are larger and are often referred to as "full body" cameras or "box cameras". They are usually sold without a lens, which gives you the advantage of being able to choose the right lens for the application.
Pan/Tilt/Zoom cameras are still relatively expensive and are typically designed for select applications such as in law enforcement and casinos. As the name implies, PTZ cameras can pan, tilt and provide optical zoom and are best deployed when an operator is available to actively monitor and manipulate the PTZ camera.
Spy cameras are small and often disguised making them the cameras of choice for covert applications.
Most cameras have a built-in 3.6mm lens that provides roughly a 72 degree field of view. Figure 1.2 shows some popular lenses and their respective field of view:
Some cameras come with a varifocal lens, so the focal length can be adjusted. Please visit our Lens Comparison Tool to learn more about lenses and field of view.
Higher Resolution and HD Video
Megapixel IP cameras can capture High Definition Video (HD Video) and provide greater detail improving identification. A 2 megapixel camera is an excellent choice for an application such as capturing license plates and can cover a 24 foot wide point of entry or exit.
Electronic Pan/Tilt/Zoom (ePTZ)
Zoom has always been available with analog cameras, but is often slow and relies on live video information. With megapixel cameras, you can zoom, pan and tilt with your previously recorded video surveillance data that has been stored on a Network Video Recorder (NVR).
One of the factors that has contributed to the explosive popularity of megapixel IP cameras is their ability to provide wider coverage and more detail. A 2-megapixel IP camera can cover an area 6 times greater than an analog camera. With a 2-megapixel camera potentially taking the place of 6 Analog cameras, the installation costs can be significantly reduced (see the diagram below).
This section will help you understand basic camera specifications and their effect on the performance of the camera.
Analog camera resolution or picture quality is measured by the number of horizontal lines the chip in the camera provides. It is called "TV lines of resolution" or TVL. The higher the TVL, the better the quality of the image.
- Standard image quality is 380TVL to 420TVL.
- High image quality is 480TVL.
- Very high image quality is 540TVL to 700TVL.
Color VS Black & White Security Cameras
Color cameras are the preferred choice for most applications, however, black and white cameras are slightly cheaper, more sensitive to light and can see better in lower light conditions.
IR security cameras turn to black and white during low light conditions and return to color in good light conditions. IR cameras have gained popularity due to this flexibility.
Indoor VS Outdoor Cameras
If you are installing a camera outside and it is not going to be mounted in a weatherproof camera housing, it must be a weather resistant camera. All of our outdoor cameras are fully weather resistant.
Lux & Light Sensitivity
The light sensitivity of a camera is measured in Lux.
If a candle is one foot away from an object, it throws one foot candle of light illumination onto the object. This is about 10 "Lux," and is an informal definition of Lux. The luminescent value of Lux tries to relate the energy per unit area falling on a surface to what the human eye perceives.
|Direct sunlight||100,000 - 130,000 Lux|
|Full daylight, indirect sunlight||10,000 - 20,000 Lux|
|Overcast day||1,000 Lux|
|Indoor office||200 - 400 Lux|
|Very dark day||100 Lux|
|Deep twilight||1 Lux|
|Full moon||0.1 Lux|
|Quarter moon||0.01 Lux|
|Moonless clear night sky||0.001 Lux|
Field of View
The field of view (FOV) is the height and width of the picture size produced by a lens. FOV can be adjusted to your application using a different lens. There are two basic types of camera lenses: fixed focal (or monofocal) and varifocal (or zoom). FOV of a fixed focal lens can not be adjusted. FOV of a varifocal lens can be adjusted. Varifocal lenses are usually more expensive. Figure 1.3 illustrates the FOV of various lenses.
|Detailed Lens Chart|
|5 feet||10 feet||25 feet||50 feet||75 feet||100 feet|
|2.8mm||6.4 X 8.6||12.9 X 17.1||32.1 X 42.9||64.3 X 85.7||96.4 X 128.6||128.6 X 171.4|
|4.0mm||4.5 X 6.0||9.0 X 12.0||22.5 X 30.0||45.0 X 60.0||67.5 X 90.0||90.0 X 120.0|
|6.0mm||3.0 X 4.0||6.0 X 8.0||15.0 X 20.0||30.0 X 40.0||45.0 X 60.0||60.0 X 80.0|
|8.0mm||2.3 X 3.0||4.5 X 6.0||11.3 X 15.0||22.5 X 30.0||33.8 X 45.0||45.0 X 60.0|
|12.0mm||1.5 X 2.0||3.0 X 4.0||7.5 X 10.0||15.0 X 20.0||22.5 X 30.0||30.0 X 40.0|
|16.0mm||1.1 X 1.5||2.3 X 3.0||5.6 X 7.5||11.3 X 15.0||16.9 X 22.5||22.5 X 30.0|
|25.0mm||0.7 X 1.0||1.4 X 1.9||3.6 X 4.8||7.2 X 9.6||10.8 X 14.4||14.4 X 19.2|
|50.0mm||0.4 X 0.5||0.7 X 1.0||1.8 X 2.4||3.6 X 4.8||5.4 X 7.2||7.2 X 9.6|
|75.0mm||0.2 X 0.3||0.5 X 0.6||1.2 X 1.6||2.4 X 3.2||3.6 X 4.8||4.8 X 6.4|
By knowing the object distance and the required target area, you can determine what lens is required for your application.
For example, using the chart above for a 1/3-inch format camera, viewing an object at a distance of 50 feet with a target area of 15 feet by 20 feet, scan down the "50 feet" column to the stated target size; scan left to see that a 12mm lens is required for that application.
Auto Iris VS Manual Iris
Auto iris lenses are a good choice for locations where light is constantly changing, such as an outside parking lot and building entrances. The iris for these lenses automatically opens and closes according to the changing light conditions. Manual iris lenses are a good candidate for areas with consistent light, such as shopping centers, schools, libraries, and offices. Manual iris lenses are good for these types of locations because the iris setting of the lens only needs to be set once during the installation. Manual iris lenses are less expensive than their auto-iris counterpart.
With regard to surveillance and digital video recording, there are 3 main categories of recording equipment: PC-based DVRs and Linux DVRs and NVRs.
PC-based DVRs are built around a PC running on the Windows operating system. In addition to the usual components that are used to build a PC, a video capture card with 4, 8, 12, 16 or 32 camera inputs is required. The capture card receives analog video from the cameras and converts it to a digital signal. It then compresses that digital signal and stores it on the hard disk drive for archiving and playback. The DVR software also provides live view, remote access, camera control and other administrative functions. PC-based DVRs are easier to use, more feature-rich, and usually cost more than standalone DVR's. You can add more cameras to a PC-based DVR at a later time by adding additional video capture cards or extension cards (as available per manufacturer).
Some people are under the misconception that any personal computer with a DVR capture card will do the job. Many crashes, system lock-ups and instabilities that consumers (end users) are faced with can be blamed on poorly designed computers that do not have the processing power for handling multi camera video processing.
Our PC-based DVR systems are built using name brand components like Intel-based motherboards, Intel processors and Seagate hard drives. Each system is hand-built by a seasoned CCTV veteran in our state of the art lab. A second technician performs a 72 point inspection of the system to ensure that all the hardware and software configuration settings are correct. The surveillance system you get from Virtual Surveillance comes preconfigured, Plug-N-Play and ready to go so the only thing you need to do is run the cable and connect the cameras to the DVR. We warranty our DVRs for parts and labor for one year.
Linux DVRS, also referred to as standalone DVRs run on Linux operating systems that are designed to run a single application. Standalone DVRs are not as feature-rich as their PC-based counterpart, but are a good choice for those less comfortable with PCs, or for applications where the environment would inhibit the use of a PC. They are more cost-effective for some applications. The Linux DVR software provides live view, remote access, camera control and other administrative functions; however some of the entry level standalone DVRs may not offer remote access.
Motion detection is built into the DVR software and is not a camera function. DVR software analyzes the video frames coming from the camera frame by frame and when it detects change in the frame or movement it will start recording. The sensitivity of motion detection can be adjusted to increase sensitivity or to eliminate false triggers. The more sophisticated DVRs allow the user to define areas where motion can be ignored, such as ignoring the movement of a ceiling fan. Other advanced features are available such as object left behind and missing object detection.
Most security camera video signals are transmitted using coaxial cable like RG59 and RG6. The most popular cable is Siamese Cable, which is a combination of RG59 for video and a pair of 22-gauge wires in one jacket for power. This design makes it so that you only need to run one cable for each camera. This type of cable is good for runs under 750' and comes on spools of 500' or 1000'. Using RG6, you can achieve runs longer than 750'. However, most CCTV professionals use CAT5e and Balun connectors for cable runs over 750'.
Pre-cut Plug-n-play Siamese Cable is available from 25' up to 150' and is a good choice for a casual install.
Depending on the type of DVR, video from cameras can be displayed on a regular TV monitor or PC monitor. Most PC-based DVRs and recent Linux DVRs provide both options.
Each camera requires a power source. There are two types of power supplies: 12V DC and 24V AC. Most cameras operate on 12V DC.
Individual power supplies are a good choice for 1-2 camera projects. If you have 3 or more cameras, a multi-port power supply is advisable. You can connect 4, 8 or 16 cameras to a multi-port power supply.
We hope this guide has been helpful to you. If you have any questions, please do not hesitate to call our knowledgeable staff at 866-424-9070 for expert advice.