Whenever you’re comparing video security cameras and systems, you’ll see cameras described in terms of optical zoom and digital zoom capabilities.
In this post, we explain difference between digital zoom and optical zoom and why it matters in video security system design.
Optical Zoom
With optical zoom the focal length of the lens actually changes as you move closer to or away from the point of focus.
Inside a digital camera you have an image sensor. With optical zoom, the lens moves farther away from the image sensor as the zoom increases.
In effect, the camera lens is magnifying the focus area through the optical zoom functionality. Optical zoom in a security camera is akin to looking at an image through binoculars. You’re actually getting a “close-up” view through magnification.
Digital Zoom
Digital zoom is akin to cropping an image so that it appears to be magnified. It’s an artificial process that creates the impression of magnification through the cropping away of extraneous portions of the scene the lens would otherwise be showing in the field of view.
The focus area appears to be magnified, but it’s really just the elimination of the portions of the picture that you are less interested in through the cropping effect.
Why Does Optical vs. Digital Zoom Matter With Security Cameras?
Assume you have a security camera set up at the point-of-sale area of a retail store and an incident comes up involving the fraudulent use of a credit card.
With a digital zoom security camera, the attempt to “zoom in” to identify information on the credit card or ID being passed to the clerk would likely be futile. The attempted close-up would most likely be too blurry to be of much help.
An optical zoom camera, however, might provide the level of detail needed to confirm the credit card number or other identifying information about the suspect.
The downside to a single camera setup with optical zoom is that you lose surveillance coverage of the wider area otherwise covered by the camera as you zoom in on a particular area.
As another example, assume you have a large, fenced in yard area surrounding a contractor supply facility. The digital zoom cameras give you coverage of the whole area, but you won’t be able to zoom in as closely at high resolution to get a solid ID on a suspicious vehicle. The optical zoom camera can provide that coverage, while the digital zoom cameras can be positioned to provide maximum coverage.
Which Is Better: Optical Zoom or Digital Zoom?
For image quality purposes, optical zoom will always produce the best quality images for close-ups, but the quality comes with tradeoffs. With optical zoom, the field of view decreases as you zoom in. This means a optical zoom leaves certain areas “uncovered” during the zoom process, assuming you don’t have other cameras covering the broader area.
Another factor with optical zoom, is that you can’t use optical zoom on footage that’s already recorded.
Incorporate Both Optical and Digital Zoom Cameras in Your System
Ideally, you’ll use a combination of optical and digital zoom equipped security cameras, in most instances, to maintain surveillance over the entire area being protected while allowing for close-ups of key areas with cameras capable of optical zoom.
In our next post, we’ll take a look at a specific use case of one of our metal recycling facility customers where the optical zoom capabilities allow management to view loads remotely, assess the materials quality, and guide the staff on the ground on how to quote the load.
Contact Vulcan Security Systems in Birmingham, Alabama
References:
For more on the difference between optical and digital zoom, including the impact of focal length of lens: https://www.lifewire.com/understand-camera-zoom-lenses-493015
