How to Pick the Right Camera Lens
By Christian M Gillman
When building a surveillance system for your home or business a little planning can go a long way in making sure you find the right security camera and CCTV lens combo. By heeding a few of these tips and gaining some knowledge; you will make it that much easier to find the perfect CCTV lens.
Lens Selection Often Drives Camera Selection
The type of CCTV lens you choose to use with your security camera can often drive the type of camera you will use as well. The reason for this is due to the fact that different style security cameras support different format lenses.
If you already have a security camera make sure you know what type of lenses it supports. For example a mini camera is unlikely to support a zoom or motorized type lens; whereas a C/CS mount type security camera would. The C/CS mount camera however would not support M12, M9, or other types of mini CCTV lenses.
CCTV Lens Focal Length
To determine what focal length you are going to need you can use a lens calculator. You will first need to assume a fixed width of view at a particular distance, and then plug this information into the lens calculator to determine what focal length is best suited for your application. Usually a quick Google search can help you find a lens calculator for the different format CCTV lenses out there such as 1/3", 2/3", 1/4", etc...
Now something you should keep in mind is that after you determine your focal length you need to decide on whether you want a fixed focal length or a varifocal type CCTV lens. The answer to this hinges on if you plan on changing the view at all. If you want to be able to change the view; then you should find a varifocal type lens containing your needed length in its range. If you don't need to change the view of your camera at all; then it would be wise to just stick with a fixed focal length.
Knowing The C/CS Mount Lens Difference
When it comes to box style security cameras, they are categorized into 2 mounting types; C or CS mount. Most of the modern cameras you see today use the CS mount format because it allows for the use of both C and CS CCTV lenses.
To be able to use a C mount lens on a CS mount security camera you will have to be sure you have the proper 5mm adapter ring to allow the lens to get the proper distance from the imager. Be warned however that if this ring is present when you have your CS mount lens mounted it will not allow for a proper focus, and it could potentially damage your CCD imager.
On the other hand a CS mount CCTV lens cannot be used with a C mount security camera, as it will not be able to get close enough to the imager to achieve a proper focus.
Optical Zoom vs Digital Zoom
This topic is somewhat more related to the zoom CCTV lenses and the capabilities found on the camera, but it is something good to know when dealing with a zoom capable security camera and lens.
Optical zoom is generally the better of the two and it's your camera/lenses ability to bring the image in front of you closer without loss of resolution.
Digital Zoom is your camera simply enlarging a portion of the image you see and showing it to you. This technique results in a loss of image quality.
Christian M Gillman has worked in the surveillance industry for over 6 years. Subscribe to our monthly newsletter, learn more about surveillance, and find great products at http://www.cu1.com
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