How To Select an IP Camera Lens

January 27, 2011 by Nathan Miloszewski

There are several elements that affect an IP camera’s image quality and field of view but the one component that is affected first, the piece that is in the first line of approach for a source of illuminance is:  The IP camera’s lens.

IP camera lenses dutifully perform several key funtions:

  • Defining the field of view:  Defining how much detail and how broad the scope of a scene will be captured and ultimately, displayed.
  • Controlling the amount of light:  Controls how much light gets passed to the image sensor so that an image has the proper exposure.
  • Focusing:  Maintain proper focus by adjusting elements within the lens assembly or, by adjusting the distance between the lens assembly and the image sensor.

When selecting an IP camera lens the field of view that you need or desire for you application will determine the type of lens you select.

There are (3) field of view types and (3) main types of lenses.

Field of View

When selecting a lens ask yourself which field of view you need.  Again, the field of view is the amount of area covered and the level of detail to be viewed.  In short, this is determined by the focal length of a lens and the size of the image sensor.  Those specification are also usually found on an IP camera’s data sheet.

There are (3) field of view classifications:

  1. Normal View: Same field of view as the human eye
  2. Telephoto View: Magnification of a narrower field of view providing finer details than what can be delivered by the human eye.
  3. Wide-Angle View: Larger field of view with fewer details than in normal view.

Lens Types

Depending upon which field of view you want will determine the type of lens you need.  There are (3) main types of lenses:

  1. Fixed Lens: Only one field of view (either Normal, Telephoto, or Wide-Angle view) is available because the focal length is fixed.
  2. Varifocal Lens: Offers a range of focal lengths and therefore, different fields of view. The field of view can be manually adjusted and whenever the field of view is changed, the user must refocus the lens manually.
  3. Zoom Lens: Similar to a varifocal lens in that different fields of view can be selected however, there is no need to refocus the lens once the field of view has been changed.

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