You have to be as careful about selecting security camera lenses, as you are about selecting a surveillance camera. A lot depends on getting a good footage from your security camera. The picture quality depends a lot on your security camera’s lens.
While considering lenses, you will come across a factor called field of view, (FOV for convenience), which is nothing but the height and the width of the picture produced by the lens. Different applications might need different FOV. You might want to change this factor to suit your needs at different points of time. This flexibility is offered by varifocal camera lenses.
Another important factor is the light condition of the place in which the camera is set
up. If the lighting does not vary too much, like in a store or office, then the best bet is manual iris lenses. But for areas, like parking lots for example, where the light is constantly changing, you must go for auto iris lenses. These lenses adjust their iris opening depending on the available illumination to give you better images.
Make sure you take the time to figure out what type and size lens you need before purchasing by looking researching, etc. One good resource is our lens comparison tool, which lets you see the field of view of different lens sizes at different distances from objects. That should give you a much better idea than just estimating.
October 21st, 2009 at 12:14 pm
[...] tested this in our shop with an auto iris lens on the camera. Whenever we made changes to the setting we would see changes in the image quality [...]
November 24th, 2009 at 1:11 pm
What is the most important thing to look for in a lens?
December 17th, 2009 at 12:23 pm
Cameron, there are a few important things to look for:
First, are you using this lens for general surveillance or are you wanting to see something in detail?
Second, You will need to get the distance of the area you are wanting to view and the height at which the camera will be mounted. You will need to do the Pythagorean Theorem to figure out your true distance. (The horizontal line will be your distance, the vertical line will be the height of the camera and the slanted line will be the true distance from the camera to what you are trying to view)
Third, Will a fixed lens (3.6mm) suffice, or will you need an adjustable lens (4-9mm) to manually adjust the zoom at the camera once it is mounted?
Fourth, Determine if you will need an auto-iris lens or manual-iris lens. In most cases, you will probably need an auto-iris lens, FYI. An auto-iris lens adjusts to changing light conditions whereas a manual-iris lens does not. For example, you would use an auto-iris lens outside and you could use a manual-iris lens in a warehouse that is lit 24/7.
Hope this helps!
Chris Belote
ApexCCTV Team