Security Camera Guide
Which type of Security Camera should I use?
A security camera can come in many different styles including dome, bullet, infrared and box. The CCTV camera that will work best for your application will depend on several factors such as whether you will use the security cameras inside or out, during the day, nighttime, or both.
Bullet style security cameras are the most popular. They can be used inside or out. These security cameras come in black and white in color and come with all of the required mounting hardware. The security camera casings are weather resistant and don't require added external protection. Most security cameras have a fixed 3.6mm lens that allows you to see facial features out to about 35 feet and provides a 90 degree angle of view. This is the widest angle you can have without distorting the picture. Click here for more information about bullet security cameras.
Infrared security cameras are very popular as they allow an image to be seen in little or no lighting conditions. These days many security cameras offer infrared and can be used inside or out. The cameras have small bulbs installed around the outer edge of the lens which allows the security camera to see in no light for up to 25 feet to 100 feet, depending on the camera - even further with a little bit of light (like street lighting or an outside light.)
The advantage to box security cameras is that the lens can be changed. You'll want a special camera lens if you need to see further than 35 ft. The color box security camera allows you to change lenses on the camera giving you the ability to zoom into a particular area. Varifocal camera lenses allow you to adjust the focus from 5 to 50 mm. These lenses can be used inside only unless you put it in special housing for outdoor use. Click here for more details about box security cameras or Security Camera Lenses.
Dome security cameras basically provide a different look. The electronics inside the camera are the same as a bullet or box camera, but with a more tamper-resistant enclosure. Click here for more facts about dome security cameras.
The term Bullet Camera comes from its resemblance to a rifle bullet. Generally long and tapered like a cylinder, it looks like an oversized ammo cartridge. Bullet cameras offer a versatile mounting bracket that can be pointed in any direction.
Bullet cameras can be both fixed lens or varifocal. Fixed lens cameras usually come in 3.6mm. Other lens sizes are available but 3.6mm is the most common. Varifocal lens can be adjusted on the camera with a screwdriver at the time of mounting. Varifocal lens are usually 2.8mm to 12mm which will allow you to zoom to the target and maximize
Modern CCTV cameras capture images in color which is best for daytime lighting. For nighttime viewing, many cameras include infra-red bulbs and a night vision mode, which captures images in black and white at night. The cameras will display color during the day and automatically switch to black and white infrared viewing when light levels are low. Resolution levels are usually about 500-700 lines, any higher resolution would lead you to an IP or HD-SDI solution. For color, the higher resolution the better the picture.
Bullet cameras contain the same electronics as every other camera. Nothing makes a bullet camera better than a dome camera or box camera. They are just a different shape and allow for different mounting positions.
Bullet cameras most commonly use 12 volt DC power. However, their are some models available that are dual voltage, 12 volt or 24 volt. You can find the bullet style cameras in Analog, IP, and HD-SDI formats.
The Dome Camera is obviously named for its dome shape. Everyone has seen these security cameras in businesses and stores. Because of its shape, its difficult to tell exactly where the camera is aiming unless you see it up close. Dome cameras are generally used inside buildings, although the armor domes can be used outside as well.. You can mount them on the ceiling or on a wall. They are available in black and white (b/w) and color, and the basic unit has good video resolution (500 lines up to 700 lines).
An advantage of a dome camera over a bullet is that a dome is more difficult to tamper with. A bullet camera can easily be moved by someone who can reach it, or can be covered by something like a jacket. Due to the design of a dome CCTV camera, they are sometimes better suited for areas where they may be in reach of someone who is wishing to tamper with a camera. They are also lower profile than a bullet camera, which makes them more difficult to notice.
Dome security cameras work great both indoors and outdoors. Many common uses are indoors in the corner of the room to capture large area, or in a hallway. Outdoors the can be used under an overhang or on the side of a building.
The advantage to a box camera is that the lens can be changed. These cameras are also sometime referred to as a "c-mount" camera. If you need to see further than 35 or 40 ft then you'll need a c-mount camera with a special lens. C-Mount lenses are available from 4mm to 100mm. A 4mm lens provides facial detail and a 70 degree angle of view focused up to about 35 ft. An example of where you might use a fixed 4mm lens is in a small office, or at home to focus on your driveway. Refer to our LENS CHART HERE
If you want to use c-mount cameras outside, you must put them in an outdoor camera housing. See Outdoor Housings HERE
CCTV lenses are available in two different lens mounts. "C-mount" lenses have a flange back distance of 17.5mm; "CS-mount" lenses have a flange back distance of 12.5mm. The flange back distance is the distance from the flange of the lens (beginning of the lens mount) to the focal plane. All of the C-Mount cameras we sell can be adjusted for installation of a CS-Mount lens as well as a C-Mount lens. See Varifocal Lenses HERE
Which Security Camera Lens Should I Use?
How far you need to see will determine what security camera lens you should use to best fit your application. A 4mm lens will give a 70 degree angle of view with 35 feet of facial detail. This works great for residential or small office security camera applications. If you need to see further you would go with a higher powered lens. Keep in mind that the further you want to see will narrow the field of view of your picture.
A higher millimeter lens will provide further distance, but narrows the field of view. So, a 16mm lens would provide about a 15 to 20 degree angle of view at a focus distance of about 35 ft (or a 70 degree angle of view at about 140 feet). In general, a 8mm lens is like a 4mm lens zoomed in 2 times. Similarly, a 16mm lens is like the 4mm lens zoomed in 4 times.
Many times, the best option is to use a varifocal lens. This will allow you to vary the focus from 5 to 50mm. So when you install the camera you can fine tune the focal distance and angle of view. An example of where you might use a varifocal lens is outside (or inside) a large commercial building where you need more distance than 35 ft. and the varifocal lens will allow you to adjust the focal distance to your preference.
What If I Do Not Know Exactly How Far I Need To See?
Instead of going with a fixed focus lens you can go with a varifocal lens. With a simple adjustment you can manually zoom in or zoom out and focus the camera to the exact distance needed to get a clear picture. Varifocal lenses come in all different sizes: (3.5-8mm; 9-22mm; and 5-50mm) just to name a few. This is the best option for large commercial applications because you can adjust the focal distance to what works just right.
A Pan Tilt Zoom camera (PTZ) allows you to pan (back and forth), tilt (up and down), and zoom (focus in and out) your camera remotely. The PTZ is controlled using a remote PTZ controller or you can control it through the software of your DVR system or an external controller. The disadvantages of a PTZ camera is that they can be more expensive compared to a normal camera. And all the moving parts make it susceptible to wear.
Pan Tilt Zoom cameras require an additional control wire run from the CCTV recorder to the camera in addition to the standard coaxial and power cables. There are all-in-one video/power/control wires available, or if you already have coaxial and power cables run a single control wire can be added to the run. Many installers use two twisted pairs from a CAT5 ethernet cable to create ther control wire. Megapixel IP PTZ cameras can transmit their control data over the ethernet cable connected to the camera.
As with other camera types, PTZs can be found in analog, IP, and HD-SDI formats. With their large viewing range, a PTZ camera is best suited as an "overwatch" type camera taking the place of four individual cameras. They can also be rather large in size, heavy, and require very specific mounting conditions. Those are factors to consider when looking at a PTZ camera.
License Plate Recognition (or LPR) cameras are becoming very popular in a number of scenarios. LPR cameras are very different in the way they process the images. LPR cameras are designed to capture license plates in all types of conditions. License plate cameras are designed to capture vehicle license plates in video. There are some systems that are capable of seeing the license plate and recognizing the characters on the plate and saving the information to a database that can be searched later.
A good LPR camera should have the ability to be adjusted to the environment to capture plates successfully. Not all cameras are capable of recognizing license plates. A standard CCTV camera may not have a fast enough lens, or deal with adverse lighting conditions. In general, you do not want to have the camera looking at the plate at any angle greater than fifteen degrees. This means that a camera mounted on a roof of a building or up high is not in the correct position to see and capture license plates clearly. This is partially due to the reflective nature of plates, so trying to see a plate at an extreme angle will not be possible due to glare.
The biggest difference between Analog and IP is the video quality. IP cameras produce HD quality video. Megapixel come in different resolution ranging from 1 megapixel to 5 megapixel and can be found in all of the same type of enclosers that analong cameras come in. If you are looking for true HD video quality, then you need a camera that is at least 2 megapixel as that delivers the full 1080p resolution.
IP cameras can also include a fixed lens or a varifocal lens. Megapixel cameras can be powered using standard 12 volt DC or PoE (Power over Ethernet). Some cameras are dual voltage, 12 volt or 24 volt. Megapixel cameras can be accessed through the internet or NVR system.
Due to the higher resolution picture the cameras produce, an IP camera will require more hard drive space in the NVR system. Network Video Recorders function just like a CCTV surveillance recorder, where the camera footage is recorded to a hard drive. For IP cameras it's recommended that the NVR has at least 2tb of storage. The more cameras on the system, the more storage will be required to store footage.
The latest CCTV technology is HD-SDI, or HD CCTV. Just like with IP Cameras and Analog cameras, you can find HD-SDI cameras in all sorts of enclosures such as bullets, domes, boxes, and even PTZs. HD-SDI is different from IP in that it delivers a full 1080p digital image over pro-grade coaxial cable with standard twist-on BNC connections to the digital video recorder.
What HD-SDI gives you is crisp and smooth high-definition video without any latency or delay in the image. This is very important for high-risk areas such as cash registers, banks, and casinos where clear and smooth video is required to see details on things such as money changing hands. The high resolution video also makes large areas easier to cover thanks to the size of the image that the cameras can capture and the detail that can be seen in the image.
Lens: The lens determines the field of view the camera provides. Lenses range from 2.8mm to 18mm on an average. The larger the lens size the farther it will view. The draw back to a 12mm or 18mm lens is that the horizontal view narrows to as little as 15 feet.
*Many of our customers require a standard fixed wide angle 3.6mm lens. They are designed to be installed in a corner, provide a 90 degree field of view, and provide effective surveillance in a 30 x 30 foot area. If you need to adjust the angle and are not sure when viewing a cash register or looking down aisles, we recommend a vari-focal lens which you can adjust manually based on the angle and distance of the camera to the subject. For example, with a cash register we recommend a 4-8mm vari-focal lens so you can manually adjust and capture the money, hands, and register close up. When in doubt, go with a vari-focal adjustable lens.
Lux and low lighting chart
During the day the amount of illumination reaching a scene depends on the time of day and atmospheric conditions. Direct sunlight produces the highest-contrast scene, allowing maximum identification of objects. On a cloudy or overcast day, less light is received by the objects in the scene, resulting in less contrast. To produce an optimum camera picture under the wide variation in light level (such as occurs when the sun is obscured by clouds), an automatic-iris camera system is required. Typically, scene illumination measured in foot-candles (ftcd) can vary over a range of 10,000 to 1 (or more), which exceeds the operating range of most cameras for producing good quality video images. The chart above summarizes the light levels occurring under daylight and these low light level conditions. The equivalent metric measure of light level (lux) compared with the English (ftcd) is given.