If you are thinking of buying a CCTV camera for the first time you could find the choice a little baffling. What lens to choose? CCD or CMOS? Wired or Wireless? 16mm to 3mm?
I will try to give a quick guide to help you choose.
I will start with CCD or CMOS? simple. CCD will give you a better picture quality then CMOS which are used on the low end CCTV cameras. These are still useful if you are on a budget.
Wired or Wireless? I get asked this everyday. I try to advise buyers to opt for the wired option if possible as this will give 100% reliable results even thought is may be less convenient, it is the best option.
Wireless can be very useful but has the drawback of suffering from interference from a range of other devices including, the now very popular, wireless internet. You could find that your wireless internet will not function at all if you have a wireless CCTV system. Some people do get on with wireless very well and everyone's circumstances are different but I would not recommend wireless if you wish to use motion detection recording. Any interference would trigger the DVR to start to record and waste a lot of HDD space.
Which lens to go for? OK, imagine a CCTV camera is a Camcorder. If you zoom in you will get a close detailed look but you will not have a wide angle. If you zoom out you will have a wider angle but not such a detailed image. It is the same with a CCTV camera.
The bigger the lens in any listing description, the more zoomed in it will be. ie: 16mm is quite zoomed in and this is what a garage would use to look at car number plates in a forecourt. At the other end of the scale the same garage may use a 4mm lens to view the whole forecourt in a wide view.
You can buy Vari Focal lenses. These eliminate the chances of choosing the wrong lens because they are adjustable. These are very popular but more expensive.