Fixed lenses are commonly seen in the small, easily concealed weatherproof ‘bullet’ cameras that are sealed, and fairly inexpensive. Therefore, the fixed lens is still a mainstay of video surveillance systems for the general consumer. Choosing the best focal length for your particular situation is important. You need to ask yourself these key questions:1-Is the camera just going to be used for a wide coverage (say to cover the parking lot at my business or my front yard) to monitor general activity with little detail?
2-Is the camera going to be used to cover a specific narrow target area (say an entrance way or doorway) where I want to identify the face of the subject, and therefore need greater magnification? Here are some steps that may be useful in determining the best focal length security camera: First, determine the target distance – that is how far away your subject is likely to be. The idea here is to ascertain the target distance based on the situation. It’s not an exact assessment, but choose a target distance that is representative of the area you want to cover. For example, if you want the security camera to keep watch over your car parked in the driveway, choose a spot to mount the camera and then measure the distance from the camera to the far end of the car furthest from the camera. That way you’re able to cover the car and the surrounding area that a perpetrator might have to cross in order to access your car. The idea is to choose an average distance away from the camera that the perpetrator is likely. Next, determine the width of the target area – that is the width of the area that you want the camera to cover. You want to choose a coverage area that is wide enough to capture the action, but not so wide that the magnification is diluted. Remember there is a trade off between coverage area and magnification, in that if you increase one you’ll decrease the other (all other things being equal).Here’s where you need to make a decision as to whether you want more magnification or greater coverage area. If you want more magnification then you would choose the longer focal length, if you want a wider coverage area then choose the smaller focal length.For example, let’s say that you have a security camera and your target distance is 25 ft. and your desired target width is 15 ft. Remember, there is a trade-off between magnification of detail and coverage area!
If you want a better chance of identifying your subject at a distance you might want to go with the stronger focal length of say 16 mm to give you better detail. Keep in mind though, the field of view will be narrower which entails a smaller coverage area. For security camera with the target distance at 25 ft., using a 16 mm lens gives you are coverage width of only 7.5 ft. This lens may help you get a subject’s face in detail, but you may just miss him if he doesn’t walk through the narrow target area! (This high magnification focal length might be good for a doorway or entrance that is a narrow target area is or if your target is at a greater distance).
Security Video Technology (SVT) is a nationwide security solutions contractor and security surveillance integrator. We are based out of the greater New Orleans area and service clients primarily along the Gulf Coast from Tallahassee, Jacksonville, Destin, Fort Walton, Pensacola, Miami, Florida, Mobile, Fairhope, Gulf Shores, Alabama and Gulfport, Biloxi, Mississippi east to Baton Rouge, Lake Charles New Orleans and Shreveport, Louisiana as well as Beaumont, Dallas, Houston, Texas on the west.