Surveillance cameras come in many different sizes, shapes, and prices. There is a lot to consider when deciding what camera will do the job you need. Off-the-shelf kits are usually very low quality and will rarely produce useful results... thus, the little bit of money spent is often a total waste. Better to do it right the first time. Besides price, the considerations are:

Color vs Black & White	B&W cameras are less expensive than Color, but the price gap has narrowed substantially. Color cameras are more pleasing to watch, and provide the ability to discern color sensitive details such as clothing, hair, skin, vehicle color, etc. B&W cameras generally can see better in lower light than color cameras. B&W cameras typically have a higher resolution than their color counterparts. (see below)
Unibody vs Traditional	A unibody camera has a built-in lens which is not changeable. Usually it is a wide angle lens which is good if the camera is mounted close to the subject or you want to view a large area. You are stuck with whatever lens the camera comes with. These cameras have a minimal amount of auto-adjustment for varying light conditions. A traditional body camera comes without the lens. You then order the lens that best suits your application. You can have a wide angle lens, a zoom lens, a varifocal lens which lets you adjust the zoom, then lock it in when you like what you see, or an auto iris lens which will automatically adjust to a wide range of lighting conditions.
Resolution	Resolution is measured in "lines" or "TV lines", and refers to how clear or defined the picture will be. A high resolution camera will send a much more crisp image which will define more detail. Low resolution would be under 300 lines. Medium resolution would be 300-400 lines. High resolution would be over 400 lines. The trick is to match the camera with equipment you are recording on. VCR's record at 350 lines (same as a TV set), so having a high resolution camera is a waste. Most DVRs (Digital Video Recorders) can make use of the equivalent of approx. 400 lines. B&W cameras typically have a higher resolution than their color counterparts. Obviously, higher resolution cameras will carry a higher price tag. This is where a lot of people waste money  buying a high resolution camera with a low resolution recorder, or vice versa. An experienced CCTV technician can guide you in this area if you will let him.
Lux Rating	The lux rating is a measure of how much light is required for the camera to produce an acceptable image. A higher lux rating means that more light is needed, and the camera will not work well in low light conditions. Therefore, a lower lux rating is better. A rating of 3 lux would be high, while some cameras can get lower than .01 lux. A camera's lux rating can be enhanced by an auto iris lens which adjusts to variations in lighting conditions to a certain extent.  Generally, B&W cameras have a lower lux rating than color cameras. B&W cameras can also see in total darkness when there is infrared lighting installed. The human eye cannot see infrared light, but to a B&W camera, infrared light illuminates the area substantially. Infrared illuminators can be purchased separately, or some cameras have them built into the camera, but have a shorter range. Sadly, color cameras do not pick up infrared light, but we do have "day/night" cameras which produce color images when there is enough light, and switch to B&W mode when the lighting is insufficient for color. Combine this with built-in illuminators, and you have a great all purpose camera. (see below)
Covert vs Visible	Covert cameras are hidden or "spy" cameras. They are either hidden or disguised as something else, such as a smoke detector, motion detector, clock, or anything else other than a camera. Visible cameras are.... visible. Covert cameras are great when you want to catch someone in the act. Visible cameras have more of a deterrent value. Most people are less likely to do something bad if they know they are being watched. Covert cameras are generally very tiny circuit board cameras and have a "pin hole" lens which can see through a very tiny hole.
Indoor vs Outdoor	Indoor cameras need no protection from weather conditions, however they may need to be placed in a vandal resistant housing if there is a concern that someone may be able to reach it to vandalize it. For outdoor purposes, there are 2 choices. First is to place an indoor camera in a weatherproof housing which could have a heater and defroster built in. Second, you could install a camera which is built to be weather resistant without a housing. The former choice is preferable if vandalism is a concern.
Day/Night Camera	This is a nifty little camera which produces a color picture by day (or whenever there is enough light for color). When the light level gets too low for a color image, it automatically switches to B&W mode and turns on the infrared illuminators so that it can see in total darkness. The images below are taken in a room which is totally dark when the lights are out.
Lens	Traditional body cameras use a separate lens. Most lens range from 3mm (wide angle) to 16mm (narrow angle). Higher than 16mm is usually considered a zoom lens and can go up to 80mm and even higher. Some lens have a fixed iris (no adjustment for lighting), a manual iris (adjusted by hand), or auto iris (adjusts automatically). There are also varifocal lens which allow you to set the angle of view (or zoom) manually until you like what you see, then lock it there. Proper lens selection requires the help of a trained professional OR a lot of trial and error.
PTZ Cameras	Pan Tilt Zoom. These cameras require a control keypad or DVR to allow you to move the camera left, right, up, down, and zoom in and out. Most PTZ cameras can be programmed with an "auto-tour" which allows you to set up a pattern that the camera will follow over and over when no one is around to do it manually. They are much more costly than fixed cameras, but can be very useful if you want to scan a parking lot, zoom in on a license plate, or follow a suspicious customer around your store.
WDR Cameras	Wide Dynamic Range cameras are a recent development. This technology adapts much better to varying lighting conditions than even auto-iris lenses do. These cameras do a great job of handling background lighting issues that regular cameras cannot handle. For instance you would get quite a good image of a person standing in front of a window with a WDR camera where with regular cameras there would be severe glare from the outside background while the person would just be a gray shadow.
IP Cameras	These cameras so not need to be hooked up to a monitor or DVR to be viewed or recorded. Instead, they are connected to a LAN (Local Area Network) just like another computer would be hooked up to the network through a hub or switch. These cameras have a web server built in allowing you to connect to them from another computer on the LAN or over the internet. For instance, you can connect to many IP cameras using Internet Explorer or similar web browsers - as long as you have the right user name and password, and your network has been set up properly. If you wish to record, you can record onto the computer through which you are viewing the camera. Be warned that the recordings will use up a lot of your hard drive unless you limit how much drive space it is allowed to use before recycling. IP cameras send their images over your network and use a fair bit of bandwidth, which may slow down your network. These cameras are much more expensive than regular cameras.
Placement of Cameras	Take time to consider exactly what you want or need to see. If you need to be able to positively identify a person, their face should fill a large part of the screen. The picture above may not be useful as evidence to the police sufficient to get a conviction if the person were an intruder. There is not enough definition to establish a positive identity sufficient for court purposes because there are very few pixels defining the person's face; therefore this could be one of several people. However, if this were a business monitoring a stock room that only employees enter, this picture may serve the desired purposes very well since not all employees will have the same build, hair density, etc.  If you want to watch a large area to see general activity but do not need to define who is doing the activity, a wide angle lens can do a very nice job for you. When picking camera locations, try to avoid pointing the camera directly into a light source in order to reduce back lighting as much as possible. For example, when placing a camera to watch an entrance that has a glass door, remember that sunlight coming through the door at times during the day might "backlight" people as they come in. Just like your eyes, the cameras will adjust down automatically because of the bright light, and all that you will see is the outline of the person coming in. If they are backlit, you won't be able to see their features and neither will the camera. In most instances, you can reduce and even eliminate backlighting problems by placing the camera at an angle to the entrance, off to one side or the other, rather than pointing straight at the door.

Common Mistakes

More is Less	A common mistake is to try and cover a large area with 1 camera. If all you want to see is a general view of the activity in an area, this is fine. But, if you want to get a good description of a person, vehicle, license plate, etc., you will not be able to do so with a wide angle coverage. In order to get a good picture of a person, their body should fill up as much of the screen as possible. In this case, more is more - the larger they are on the screen, the more pixels there are to define features; hence a better description. This point is illustrated in the pictures below; in order to get a positive I.D. on a person, you need the person's image to fill a larger part of the screen.
Backlighting	Avoid placing a camera so that the background of the image you are looking at is brighter than the foreground. Backlighting will cause the person or object you are looking at to be merely a shadow because the camera is adjusting to the bright background as illustrated below. Some cameras have a degree of backlight compensation adjustment, but you pay extra for that feature, and it doesn' t entirely fix the problem.
Quality	Myth: All cameras are created equal, and if one is cheaper, it means I am getting a better deal. Fact: The myth is a myth, but it is how most people think. Many people waste money buying something because it was cheaper - only to find out that the job it does is useless. If the purpose of your surveillance system is simply to know when someone has entered an area, then a more basic system will do. However, if you need the clarity to get a positive I.D. of a person or object, you'll need to spend more to do the job.
		For example: This is a wireless camera with receiver that we purchased  from a company that advertises extensively on the internet. It was under 200.00 Cdn. It lasted about 3 months then quit. The hassles of packaging it up and sending it somewhere in California (postage pre-paid) was not worth the effort.

 

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