Digital Zoom Vs Optical Zoom
A zoom lens allows you to vary lens focal length, and therefore make the subject larger or smaller in the image.
Digital zoom is not “true” zoom, as all it really does is digitally enlarge part of the image, which simulates “true” zoom. Typically, there is a noticeable loss in image quality when digital zoom is used, so it is really not desirable. In reality, digital zoom does nothing more than crop out a smaller section of the image. You could take picture of the scene zoomed out, crop away the undesirable portions in order to bring the subject in closer, and end up with the same result. There are people who would rather not, or don’t know how to use photo editing programs such as Photoshop, and for them digital zoom is indeed useful.
Optical zoom on the other hand, is when the camera actually brings the lens physically closer to the subject, in much the same way that binoculars do. Optical zoom is considered to be “true” zoom, as it is actually magnifying the image with the lens and not just simulating zoom, by cropping out a small section of the image. Using optical zoom enables you to get closer to the subject without loss of detail or image quality. The word “optical” references the fact that the lens is actually focusing on a smaller part of the image, with a sharper focus, which is very similar to how our eyes focus on objects that are further away.
Cameras with higher optical zoom are generally more expensive, so if you just take photos indoors then a cheaper digital camera is probably fine. If you take a lot of landscape photos, or outdoor photos that require you to focus on far away subjects, then paying more for higher digital zoom is wise.