CCTV Camera Lenses : A Beginner’s Guide

Security Camera LensesWhen designing a surveillance system for your home or business, one of the main things to consider is what type of security camera lenses you’re going to use with your cameras. This will help you determine how much light will enter the camera, what area your camera covers, and how well it can see that area. Hopefully these tips will help you choose the perfect lens!

The iris of a lens is an important detail to cover and there are manual irises and auto irises. The difference should be obvious but, what they do might not be. An auto iris lens is really quite amazing; it does what your eye basically does. The darker it gets in the area surrounding it, the more the iris opens up to allow in more light into the lens and onto the sensor chip just like your own eye does with your corneas. A manual iris on the other hand is just that, manual. The feature of auto adjusting to the environment does not come with this type of lens. You would use this type of lens where the light levels do not change such as a warehouse or office space. Since the lighting does not change there is no need for the iris to adjust and you’ll save a few bucks.

Points to Remember

  • Auto Iris vs. Manual Iris : Whether or not the lens will or will not adjust to new ambient light levels throughout the day. Pro Tip: Manual for indoor, auto for outdoor.
  • Focal Length : Affects your range, depth, angle, and field of view. Pro Tip : The larger the mm, the further you’re able to see, but the smaller the field of view.
  • Varifocal vs. Fixed Lens : A fixed lens lets you view objects at a specific distance whereas a varifocal lens allows you to set the viewing distance.

The focal length is an equally important aspect of a lens. The focal length is what tells you your range, depth, and angle of view. This will always be measured in millimeters; the larger the mm the narrower your view. However, with a large mm lens you Security Camera Lens Field of View Comparison Chartget an increased view in distance. There are fixed lenses and varifocal lenses. A fixed mm lens would mostly be used for viewing a fixed location for the entire time that camera is there i.e. an office, door, or hallway; whereas a varifocal lens is made to be adjusted. You can use this type of lens for many purposes. I would normally recommend this type of lens to someone that does not know the exact distance they need to be covering. This can come up when trying to watch a parking lot or parking garage. You would use the varifocal lens to adjust the field of view to your specific needs and if your needs change in the future, adjust the lens!

Choosing the right lens can be a very difficult task and the expert security consultants at ApexCCTV are ready to field any questions you may have about the right lens for your application. Give us a shout @ 800-997-8460 and we’ll go our utmost to get you the right fit!


3 Comments on CCTV Camera Lenses : A Beginner’s Guide

  1. KD on Wed, 19th Dec 2012 5:29 pm
  2. WOW!! This is awesome information Brandon. I can see alot of end users and installers benefiting from this blog. I look forward to your next post. Happy holidays!

  3. Brian on Thu, 27th Dec 2012 4:59 pm
  4. This is very helpful information. Thank you for writing it!

  5. Security Tech Guy on Wed, 9th Jan 2013 8:33 am
  6. I have directed several installers to this image in the past…. there is no way to make it more clear than that image right there.

Tell me what you're thinking...
and oh, if you want a pic to show with your comment, go get a gravatar!