Zooming on your video borescope involves getting a closer view of distant surfaces. Optical zoom uses an actual lens adjustment and digital zoom adjusts the digital image itself.
Optical zoom: An optical zoom is a true zoom lens, like the zoom lens you’d use on a photographer’s camera. There are no video borescopes manufactured with true optical zoom at this point in time.
Digital zoom: Some video borescopes offer a digital zoom, which is simply image processing. When you use a digital zoom, the borescope camera enlarges the image area at the center of the frame and trims away the outside edges of the picture. The result is the same as when you open an image in your photo-editing program, crop away the edges of the picture, and then enlarge the remaining portion of the photo. Enlarging the “zoomed” area also enlarges the pixels and reduces the image resolution and the image quality.