What Is CCTV?

By: Nahshon Roberts

CCTV stands for closed circuit television. It is a system where the circuit is closed and all the elements are linked. This is different from broadcast T.V. where tuners pick up the signals from the airwaves. For purposes of this article, linked means connected by wiring, microwave, infrared, etc.

What's It Used For?

The most obvious and common use for CCTV is for security. This type of installation is used in a variety of locations such as stores, banks, and government buildings. However, there are so many other uses. It can be used for monitoring traffic. It is used in sports stadiums to focus on the audience. It can be hidden in trains and buses to detect vandalism. It can be used to monitor animals in a zoo. It can even be used to reproduce infrared vision. The applications are almost limitless.

What's In It?

It all starts with the camera. This creates the picture that is transmitted to the control area. Most CCTV cameras are not fitted with lenses. They must be obtained separately and screwed on. There is a standard screw thread although there are different mounts. Not all lenses have focus adjustment. Most have iris adjustment. Some wide angle lenses do not have a focus ring. There is a BNC jack for connecting the video cable. In the case of line powered cameras, this coaxial cable also provides power. The monitor is what receives the signal that the camera creates. A CCTV monitor is similar to a television set but it does not have tuning circuits.

Simple CCTV systems consist of a camera connected to a monitor with coaxial cable. This cable also carries the power needed for the camera. This is called a line powered camera. The Pye Observation System was such a system and was popular during the early days of CCTV. It was affordable and could be set up with a minimum of difficulty. The next big step in the technology was allowing for four cameras to be connected to the monitor simultaneously. The view could be programmed to cycle through the available cameras or go to a particular camera chosen by the user.

Record For Posterity

Another big advance was when footage could be recorded and stored. The footage would be played back according to the viewing cycle the user chose. Once the footage is recorded, it cannot be changed to go to a different camera. The next step would be cameras that were able move and swivel. Simple platforms that move on a horizontal plane are called scanners. If a platform moves on both vertical and horizontal units it is called a pan, tilt unit.

The concept of CCTV is simple enough to understand. It is the application of such technology that still holds many undiscovered gems. Such a simple concept can be tapped for its limitless potential. And for the end user, it can serve as a great tool to accomplish many different things. In the end, that is the most important thing.

Beginning Photography Tips, A Few Basic Tips For Taking Digital Photography

By: Mick Legg

My first tip for taking digital photography for anyone whether they are beginning, or have some degree of experience is “don’t be frightened of your camera”. Get used to handling your camera so that you feel comfortable with it. Make sure you know where all the controls are, and familiarise yourself with their functions. This is one of the basic beginning photography tips that often gets overlooked as it is such an obvious one.

Once you are comfortable handling your digital camera and have learnt how to use all the controls and functions, my next tip for taking digital photography is to take lots and lots of pictures. The beauty of digital photography is that you do not need to keep every picture that you take. You are not paying for a long processing sequence like you would be if you were using a camera that uses rolls of film, so you can be a lot more extravagant when it comes to taking pictures. Plus you may just take a prize winning photo purely by chance, and any photos you don’t want you can simply delete.

Another of the basic beginning photography tips that people often forget is to hold the camera steady. Again this may sound pretty obvious but it’s surprising just how many of us forget this simple little tip when we rush to get a good photo. It is important to actually practice holding the camera so that you automatically steady it for every picture that you take. How often have you seen the chance of a great picture only to rush it and ruin the shot? It’s far better to get one or two great pictures than dozens of blurred or poor quality ones.

My next tip is to always make sure that you have enough memory capacity on your digital camera. There is nothing worse than coming across something that would make a great picture only to find that you have no more room on your camera. Get into the habit of going through the photos stored on your camera on a regular basis, and deleting the ones you don’t want, and downloading and storing the ones you do want onto your computer, or have them printed off. Also buy a second card for your camera so that you always have a spare one with you just in case you need it.

Once you have got this far you should have loads of photos that you have taken, now is the time to study these and see if there is room for improvement. Maybe some of them are still coming out slightly blurred, so you will need to pay attention to your focusing. Remember that a digital camera has a tendency to take a little longer to focus when compared to a camera that uses roll film.

Maybe you are not happy with the lighting on some of your pictures, so try practising using the flash. The flash on a camera is not only designed to be used when taking photos indoors, it is also great for getting good sharp pictures outside as well, especially if the subject is in shade or if the natural light is low, like in the late evening.

I suppose that one of the most important beginning photography tips that I can give you is to “get out there and have some fun with your camera”. Take loads of photos and practice as you go. Use your camera as often and as much as you can. My last little tip would to be to get hold of a good book on digital photography, this way you will get all the tips for taking digital photography and learn all the usual mistakes to avoid right from the start.

Digital Cameras Are Small And Compact And Take Great Pictures

By: David Fishman

Digital photography is a booming business and is slowly going to take over the film camera market. Compact digital cameras are the most popular and common of the camera types. To get a better quality picture you need to increase the number of pixels, so the cameras with more mega pixels will have a sharper image. Underwater digital cameras are small and lightweight, and the quality is comparable to film if you go for the higher resolution shots. Digital pictures have improved dramatically, and are now incredibly clear. The main problem that most have is that after the picture is taken many people don't develop the pictures or don't have a a way to do it.

How exactly does it differ from the traditional camera? Up to the point when the image is captured, the process is the same in both. When you release the shutter the mirror moves out of the way and the image is captured in the same way as any digital camera. Zooming in on a subject works by cropping some of the image out of the picture. The thing to remember is the higher the resolution, the more realistic the image is, matching closest what the actual image is. The image is then enlarged to fill the camera frame, by doing this you will loose the quality of the photograph. If an image is too bright or too dark you can re-take the image.

Digital cameras are not that expensive today a 2 mega pixel camera can be had for less than $50. Also important to note is the memory capacity of the camera. In other words, how many pictures will the camera hold? Understanding a little bit about how pictures are recorded on a digital camera and then subsequently saved on a computer is critical but fairly simple even for a beginner. The key to getting the best possible digital pictures is to make sure the right camera is bought. Digital cameras are becoming more and more popular. Whether your pictures are good or bad it does not matter, with a digital camera you have full control.

In burst mode the camera shoots a fast series of photos for as long as the shutter button is held down or until the camera's memory is full. In this mode the camera writes the photos to a temporary memory which is very fast but small. When the shutter button is released or the memory is full the camera starts the slow process of writing the photos to the flash memory. Memory is also a very important issue to consider.

In terms of features it may not have any more than a simple point and shoot model. Picture quality is normally an improvement from the more basic cameras. The price of a digital camera printer is lowering whilst the quality is increasing. As far as image quality is concerned, there are a couple factors - picture resolution, presence of noise in the camera, dynamic range, and the color quality of the image. Depending on the camera purchased and the accuracy of the settings, the quality can rival and sometimes even surpass a regular 35mm camera.

Basically, a mega pixel is capable of storing a million bits of information about a photo. Because the digital SLR cameras are more professional, they come with a hefty price tag.

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