of your home, business, or other property.
A fixed lens simply means that the lens’ focal length is set and cannot be adjusted.This means that the user cannot adjust the field of view, making it important for the user to pick the right focal length, as it cannot be changed once the lens is installed. This can leave you with a very narrow field of view where you need a wider angle, or a wide field of view where a narrower capture would have been more appropriate. In short, the smaller the lens is, the wider its angle will be. The larger it is, the narrower the angle will be.We will go into more detail about angles below.
Adjusted Lens (Varifocal)
A Varifocal lens, on the other hand, can be adjusted. This means that you can pick the angle of a varifocal lens, using the camera’s knobs or other adjustment settings to change the angle. While these cameras do you give you considerably more freedom when it comes to the angle of your security cameras,they are also more expensive.For those that want to be able to adjust their field of vision, get a better angle on a building, corner, or alcove on their property at any given time, or want the ability to get both sweeping and detailed shots through just one camera, a camera with a varifocal lens is the one that you want. It is important to note that the focus
will often need adjusting with one of these cameras.
No Iris, Fixed Iris, Manual Iris
Like the iris in our own eyes, the iris of a camera is used to detect light and creates the depth perception that makes it possible to determine how far things are away. The iris of a camera should be able to determine how much light the camera needs to capture,
in order to get the best picture. But not all cameras, especially security cameras, are equipped with an iris.
In some instances, they are not necessary. Some cameras will come with a fixed iris—the opening cannot be adjusted. But if the camera is in a setting where the quality of light does not change, having no iris or a fixed iris can be perfectly fine. There are plenty
of circumstances, however, where an iris could be beneficial—including any room where the lights are turned off at night, but you
still want a functional security camera.
Some cameras will come with irises, but they have to be adjusted by hand. Again, these cameras could work in areas where the
light does not often change, but when it does, it is not inconvenient to manually adjust the camera’s settings.
Auto iris, on the other hand, actually sense the light in the room and picks a setting that captures a clear, high-definition picture of
the area, that is neither too washed out or too dark. The camera uses its analog signal to adjust its iris to the perfect setting for the changing light in the room. There are some issues with these types of irises,as they can be affected by diffraction or even blurriness. The only real negative of an auto iris lens is that the owner does not have the power to adjust it, if needed.
There are three basic types of lens angles. These are 2.8 mm, 3.6 mm and 6 mm.The shortest explanation that can be given about these angles is that the lower the number, the wider the angle. For example, 2.8 mm will give you a wider shot of your property than
a 6 mm angle. Larger lens angles mean a smaller field of view, but the objects inside that field of view will be larger and sharper. Smaller lenses will give you a wider picture, with objects appearing smaller and less detailed.