- 1 What is focal length of CCTV camera?
- 2 What is fixed lens CCTV?
- 3 What is a vari focal camera?
- 4 What is the range of a CCTV camera?
- 5 How far can a 2.8 mm lens see?
- 6 Why is CCTV so blurry?
- 7 Why is my security camera blurry at night?
- 8 What causes ghosting on CCTV cameras?
- 9 What is the difference between 2.8 mm and 3.6 mm lens?
- 10 Does zooming affect focus?
- 11 How far can a 12mm lens see?
- 12 What are fixed focal length lenses good for?
- 13 What is the average focal length of the human eye?
- 14 What focal length means?
What is focal length of CCTV camera?
The focal length (measured in “mm”) of a lens determines how far the camera can see. The most common focal length on security cameras is 3.6mm, which will allow for roughly a 72 degree field of view (FOV described below). This particular focal length works well for residential or small office surveillance applications.
What is fixed lens CCTV?
Fixed or vari-focal lens A fixed or board CCTV camera lens has a set viewing angle. This means the camera lens cannot be zoomed in or adjusted in any way. Fixed lens cameras are generally less expensive so can be a good option if the layout of an area is not likely to change (such as a room in a house).
What is a vari focal camera?
A varifocal lens is a camera lens with variable focal length in which focus changes as focal length (and magnification) changes, as compared to parfocal (“true”) zoom lens, which remains in focus as the lens zooms ( focal length and magnification change).
What is the range of a CCTV camera?
They normally quote two figures, the number of TVL and the IR range. This might be called the night time range. IR range is a largely made up number based around how far away from the camera Infra red light can be detected.
|2.8mm lens||1.5 metres|
|6mm lens||5 metres|
|9mm lens||6 metres|
|12mm lens||7 metres|
|22mm lens||12 metres|
How far can a 2.8 mm lens see?
In general a 5MP 2.8mm lens will offer you around 105° field of view and a 5MP 4mm lens will offer you an 87° field of view.
Why is CCTV so blurry?
So why are we still seeing blurry CCTV footage if they’re so much better than smartphone cameras, you ask? This is because of image/video cropping on low resolution video. Blur, on the other hand, happens when the sample video is recorded in low FPS and still image is captured from a frozen image frame.
Why is my security camera blurry at night?
Basically, the IR lights are what make the security camera see in the dark. However, quite often this IR light bounces back from a close object and comes back “blinding” the camera’s lens (eye). This light reflection is what makes the image show as blurry or foggy.
What causes ghosting on CCTV cameras?
Ghost on CCTV cameras can also be caused by slow shutter speed, high gain, high DNR, high DWDR and smoothing settings. Taking the noise reduction for example, the higher the noise reduction is, the worse the CCTV camera ghosting effect becomes.
What is the difference between 2.8 mm and 3.6 mm lens?
A 3.6mm lens is designed to provide an approximate 78° field of view and is the perfect camera in most CCTV applications. Most people think that a 3.6mm lens won’t show a large field of view, but as you can see from the below images, there’s not a huge difference between a 2.8mm and 3.6mm lens.
Does zooming affect focus?
The technique of zooming in to check focus and then zooming back out to the desired focal length is common in the video industry, where lenses do tend to maintain the same focus distance across the zoom range. In the still photography world, however, lenses may shift the focus distance as you zoom in and out.
How far can a 12mm lens see?
At 12mm you will achieve around a 30° angle of view and identification at around 50 feet. The real trick is that this lens can be set to anywhere between those two different focal lengths.
What are fixed focal length lenses good for?
A fast fixed focal length lens allows action-stopping shutter speeds to be used in low-light situations. Fixed focal length lenses are sometimes the only solution for dark indoor sports photography.
What is the average focal length of the human eye?
The eye has a nominal focal length of approximately 17mm, but it varies with accommodation. The nature of human binocular vision, which uses two lenses instead of a single one, and post-processing by the cortex is very different to the process of making and rendering a photograph, video or film.
What focal length means?
Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens. The longer the focal length, the narrower the angle of view and the higher the magnification. The shorter the focal length, the wider the angle of view and the lower the magnification.