CCTV 101

On the following pages we will address these one by one. Additionally, we will educate you as to a general understanding of some not-so-obvious differences.
(back to top)

.......................................................................................................

Image Device/Pick-up Device/Image Sensor (CCD)
CCTV Cameras come in a variety of shapes and sizes. At the heart of these devices is an image device, also known as a CCD image sensor. You will see on technical descriptions that it says “1 D4” CCD or 1/3” CCD”. Without getting into very technical specifics, if all other thing are equal, a 1/3” yields better results than a 1 D4”, and a 1 D2” is better than a 1/3”. 98% of what is in the market today is 1 D4” or 1/3”.

Is there a big difference between a 1 D4 CCD and 1/3 CCD?
Yes, there is a difference. How much depends on your requirements. If you are not dealing with an overly critical situation, the difference may be minimal, but if you are looking for the best image possible, then yes. It could be the difference between being able to identify someone or not. It's just a single aspect of as number of issues we will address here. Each one having a partial effect towards the ultimate resulting image. All combined results in the difference in quality and price.

“Could I tell the difference between the two?”
If you put them side by side, then absolutely. If they weren't, you probably couldn't tell. An analogy would be if I took a photograph of something with a $5.00 disposable camera, and then took a picture with a $10,000.00 Nikon, could I tell the difference. Both, individually, may look okay. It's when you put them side by side that you see the difference.
(back to top)

.......................................................................................................

Indoor vs. Outdoor
When a camera is indoors, it is not always subject to the same concerns as being outdoors. Lighting outdoors changes throughout the day, due to the changing positions of the sun and cloud cover. It can become a factor indoors as well, as there may be exposure to windows, causing the same effects.

Question #1 to ask in making a camera selection is, “Do I need an auto-Iris?”

You will see products often advertised as “outdoor” cameras. This is a very misleading statement. Usually, the only thing outdoors about them is that they have a “water resistant” housing. Therefore the thought process is, “Okay! I can install the camera by itself outdoors, right?” Wrong! Why, because although it is water resistant, it is not “fog proof.” Environmental conditions will cause condensation. Condensation causes moisture. Moisture not only gets on the lens but does mange to get inside the camera as well. The solution is an outdoor housing that has both a heater and blower. The camera is placed inside the housing, which regulates the environment. So virtually any type camera can be used outdoors, as long as it can fit in an environmental housing.
(back to top)

.......................................................................................................

Lighting
The human eye adjusts to changing light conditions by the iris dilating and constricting. Without it, think of what it would be like – it would be either too bright or too dark depending upon how your iris was fixed.

Similarly, the camera needs to adapt to changing light conditions. One of these adaptations is performed by a function known as “auto-iris”. It works similar to the human eye allowing more light in when it gets dark, and reducing the intake of light when it's bright out. A manual iris serves no purpose in changing light conditions, as you are not going to climb up on a ladder and make changes to the lens throughout the day. A manual iris becomes applicable where you have fixed lighting conditions, such as in an interior office or hallway, which is not subject to ambient light.

Low Light

So, are all auto-iris the same? No. Some have better abilities to adapt to lower light conditions than others. Maybe you have noticed when you bought your digital movie camera; they talked about “lux”. A lower lux number camera is capable of functioning in lower light; some better than others.

So, how do I know if a camera is a low lux camera? In surveillance cameras, a low lux camera is one with a designation of 0.05 or less in color and 0.003 in black and white. When you see a referral to a camera being “ExView”, which is a Sony trademark, it identifies this as a low lux camera. What an ExView camera does when it gets dark is automatically switch from color to black and white to give the images better contrast and depth.

Infra-Red

Low light should not be confused with zero light. Outdoors, there is always some light. Indoors, you may have situations of zero or near zero light. A room with no windows and the lights turned off as an example. In these cases, a low lux camera won't produce any results and you would require an “infra-red” (IR) camera if you want to see anything. An infra-red camera has illuminators. These illuminators send out a beam, of sorts, creating visibility for the camera. The more illuminators you have, the further it reaches and the larger the area it can cover. Think of it as a flash light of sorts.

Therefore, if you have a very large dark area, the IR camera may not reach the farthest end of the area.
(back to top)

.......................................................................................................

Security
One of the other conditions with outdoor cameras is vandalism. If the camera is not inside a protective housing, there is a potential for damage. Therefore, the outdoor housing not only addresses the environmental issues, but that of camera security as well.
(back to top)

.......................................................................................................

Power Requirements
Something important to note about outdoor housings is they output 24 volt of AC current. So when you are selecting a camera that is going to be placed outdoors, try to find a camera that is capable of 24 volts AC. Otherwise, you are going to have to run 2 power lines from the location, since you can't put a 24 volt AC device on the same circuit as a 12 volt DC device, which most cameras are. Many of the better cameras are dual voltage and can use 12v or 24v, so this eliminates the problem. Some of the issues concerning installations can be found in the How to Install portion of the web site.
(back to top)

.......................................................................................................

Camera Assembly
At this junction, it is important to understand a little bit of the realities of how manufacturers construct surveillance cameras.

Virtually all CCTV camera manufacturers are “assembly” companies. The critical components, such as optics and sensors, are purchased from suppliers. The housing and non-critical components are fabricated and then all put together and assembled. There are only a handful of suppliers in the world that manufacture the pickup sensors. The main ones being: Sony, Panasonic and Sharp. This is similar in nature to the television industry, where for decades manufacturers, have either bought a Trinitron tube from Sony, or a Blackstripe tube. So it didn't matter the dozens of names on the outside of the TV it was either one or the tube inside. The same is in the camera business.

There are hundreds of manufacturers, but they all use the same primary components. There are though, phenomenal quality differences, from factory to factory. In our experience, you will find some products with a defect rate of near zero and others as high as 25%. This is an issue of Quality Control.

In the CCTV business, the Sony components are considered the premium products. It is more expensive, but the difference is apparent. Again, if we showed you a camera with a Panasonic pickup element and asked you to look at it, then showed you one with a Sony pickup, could you tell the difference, maybe? But if you put them side by side, you absolutely could. The colors are more vibrant and crisper in the Sony.
(back to top)

.......................................................................................................

Resolution
The manufacturers of the pickup elements make two basic grades for each sensor size as well as one for each of black and white and color. A standard type 1/3” CCD color is 380 lines of resolution, while a high resolution is 480 lines. In black and white, you have a standard resolution of 420 lines, and high resolution of 600 lines. When you see the varying claims of resolution above these standard specs, all I can say is beware. Again, we all buy the same products from the same factories, so the hardware specs should not be different.

Remember, if you buy a camera that is at a lower resolution, the DVR can not enhance the quality of the image. In other words, the DVR may be able to broadcast 480 lines of resolution but if it only receives 380, then that is the maximum definition you may achieve.

Which brings us to the question of what resolution of camera is needed. Each situation is different and is dependent upon our objective. There is one key that you will hear us mention all throughout our papers, which is, “You are only as fast, or as good, as you're slowest, or weakest element.” It would make no sense to buy a top of the line camera with the best of everything and then put a cheap lens on it. You wouldn't buy a Nikon body and put a $29.00 lens on it and conversely, you wouldn't take a $99.00 35mm camera and put a $5,000.00 lens on it. These are self defeating. Quality must match all the way down the line.

Where will you see the difference between high resolution and low resolution, is when, you are trying to make out details like reading a license plate.
(back to top)

.......................................................................................................

Lens Selection
When you select a lens, you are first trying to determine the area you wish to cover; the width of the shot, and where the central focal point will be. The unfortunate problem is; your needs for a shot in a particular camera view might fall into two categories. Let's take, for example, you have a retail shop, and the camera is set up to cover a large area, you may be able to see an incident occur, but not be able to distinguish the facial features because of where it occurred. So, you have one of a few choices – make sure you select a high resolution lens so you have better detail of the image, or select a higher mm lens to cover a smaller area, backed up with an additional camera to cover the balance of the target area.

There are also some other tricks you can use to minimize costs. You may not have to use a whole slew of cameras, if you know you are going to get a close-up view of a subject elsewhere. For example, if you had a camera at the front entrance to the store, that the subject has to pass through, then you have a good look at them and what they are wearing. So, even if they move about the location elsewhere, you can associate the face you saw at the front door, with the clothing they are wearing seen from a distance. To make the selection process easier our website has a lens guide, which you can reach by clicking the following link.

Although there are a myriad of lens sizes, there are a small group that comprise 95% of the market. Typically, they are 4mm, 6mm, 8mm, or a 4mm-8mm varifocal. The varifocal gives you the ability to select anything within the range. So, when you install the camera, you would make adjustments to it until it covers that area you desire. Varifocal lenses cost significantly more money then the fixed 4, 6, and 8mm lens but the quality is substantially better. There is a very measurable difference. So much so, that we would tell you, that if you purchase a high resolution camera, you would be wasting your money if you bought a fixed lens. Again, match quality with quality.

Selecting a lens, as well as the number of cameras, at times can be a difficult task because you have a balancing act of trying to keep cost down, at the same time as accomplishing your goal. So, do you go with better quality cameras, but fewer of them, or lesser quality cameras but more of them? Although, when you start to add more cameras, the cost of the DVR increases, as you require more ports. So it is all dependent on your budget. We like to try to back into a solution predicated on the budget. This way you have a matching system of quality all the way through, and one that allows for change and growth plans.

When a lens is fixed, understand the image will not get any better than the original. Can the software increase the size of an image? Absolutely, but when it does so, it pixelates, meaning it gets the fuzzies. Don't believe claims that say they can read a license plate on a speeding car at 100 feet away with a standard 4-8mm lens. It's not happening.
(back to top)

.......................................................................................................

Camera Styles
Pan/ Tilt/ Zoom Cameras
For zooming in on features at a distance, you require Pan, Tilt, Zoom (PTZ) cameras. PTZ's are very expensive cameras, and cost in the thousand-dollar and up range for a good one. PTZ's are good in that, you can set them up to do tours, (if the DVR has that ability) that you pre-program or remotely control. You can also tie them into sensors or set up motion detection, whereby in the event of a sensor or motion triggered, the camera will swing around to that location and record. The drawbacks of a PTZ, is while it is touring a large area, it may miss an event while it is on the tour.

Other Camera Styles
CCTV cameras come in a number of shapes and sizes. They, in no way, reflect the quality of the product. Two cameras, with similar components, in different shaped housing should not perform substantially different, if they are constructed properly. So, shape and size is more a preference and convenience matter. If you have a drop ceiling, a dome camera is perfect because you simply screw it flush into the ceiling tile. No need for brackets or housing. Domes come available with vandal-proof housings. If you want it to be less obvious the domes come in different diameter sizes and finishes.

Other housings may be better suited if there is no ceiling space usable. Or, it's simply too high. So a traditional camera, or other camera that can sit on a bracket, which screws into a wall, may be more practical. Again, if aesthetics is a concern there are smaller or sleeker modern looking ones in different shapes and colors, which are not as visible.

The only camera that falls into a special category is a covert camera. Covert cameras may be the size of your thumb with a pinhole lens, which can be placed behind a wall, picture, or other covering, or they are available in the form of clocks, smoke detectors, teddy bears, pens, you name it.

But beware the privacy laws regarding visual and audio surveillance is very strict, and surreptitious recording is illegal in many jurisdictions. There is an expectation of privacy and if that privacy is violated it may be a criminal offense. POSTING SIGNS ALONE, DOES NOT RELIEVE YOU OF YOUR LEGAL RESPONSIBILITY. Check with a lawyer or your local authorities.

A few years ago there was a sweep in the Northeast by law enforcement officials of reputable security dealers, where any cameras that contained a listening device were confiscated.
(back to top)