Fixed Lens or Varifocal Lens?

Easily explained, adjustability. A Camera with a fixed lens does not have an adjustable lens. In most cases the camera itself can be ajusted, turned right or left or up and down, but the lens is fixed to whatever size that it is. A 3.7mm lens for example would be considered a wide angle, a 16mm lens would be a much more narrow view. The lower the lens size the wider the view and the higher the lens size the more narrow the view. So the question comes down to, do you want to cover a large area ( a wide angle view) or focus more on one smaller area ( a narrow view).  A good example of a camera with a fixed lens, in this case a 4.3mm would be one of our Day/Night color cameras.

There is a solution if you do not know. A varifocal lens is adjustable. A varifocal lens can be adjusted  for a wide angle veiw or adjusted to a narrow veiw. There are a variety of sizes on the market. There are lens that can adjust from 2.8mm to 8mm or 8mm to as much as 25mm. However a 25mm lens is a very tight narrow view. A more common size that is excellent for most all applications is 4MM to 9mm like our Auto Iris Varifocal Dome Camera.

So which style lens is best for you? If you are covering a large area and want to see as much of that area as possible, a wide angle lens will work just fine. If you have a large area but really only interested in a particular part of it a more narrow fixed lens will work. If you are not sure just how much you want to cover or maybe your needs will change over time and you want to have a wider or more narrow view, a camera with a varifocal lens works great.