A varifocal lens is an adjustable camera lens with independently adjustable focus and zoom. This is usually done using a pair of knobs or rods located near the lens of the camera. In this article, we will outline when it is beneficial to use a varifocal bullet or dome camera.
Understanding Angle of View
The Angle of View is an important factor in deciding which camera to use and where to position it. A wide angle is great for capturing a large area, but it is hard to recognize a face from more than 40 or 50 feet away, even with a 1080p camera. A narrow-angle makes it possible to recognize someone’s face from 75 and even up to 100 feet away with a 4MP camera using digital zoom, but the area you can cover is more limited.
The shorter the lens length (or focal length), the wider the angle of view is for that camera. For example, a 2.8mm lens will have a slightly wider angle of view than a 4mm lens. Arcdyn varifocal dome and bullet cameras are adjustable from a 2.8mm setting to a 12mm setting. This means that when you have the lens set to 2.8mm, or the zoomed out setting, you have roughly a 95˚ Angle of View, and when you have the lens adjusted to 12mm, or zoomed in, you have roughly a 30˚ Angle of View.
Specific Uses for Narrow Angle of View
A varifocal camera can be useful if you want to focus on the end of a longer driveway, to a distant gate or property entrance, or on a dumpster at the far end of your business’ parking lot to prevent illegal dumping.
There are many unique scenarios that might benefit from the use of a varifocal camera, using a tool like our Angle of View Calculator can help you decide the best lens length for you.
Tips for Adjusting a Varifocal Camera
Finding the perfect setting for your varifocal camera can be a little bit tricky, but there are a few tips and tricks you can do to make it easier on yourself when installing Varifocal cameras.
The first is to get your remote viewing app configured before installing and adjusting the camera. That way you can view the camera live on your smart phone while you install the camera. It is also helpful to have a helping hand to watch the camera while you install the camera, that way you have both hands available when up on a ladder.
If you think you may need to adjust the level of zoom periodically, you should consider a varifocal camera with a Motorized Lens. All of our HD+ Varifocal cameras have a motorized lens that will allow you to adjust the zoom and focus from the NVR or your smart phone. This is different from a PTZ camera since you can only Zoom, but you cannot Pan and Tilt.