Optical zoom works much like the zoom lens on a 35 mm film camera. It changes the length of your camera’s lens and draws the subject closer to you. The optical zoom keeps the quality of the picture. Digital zoom works differently. It simply takes the picture and crops it then enlarges the part that is left. It causes the quality of the photo to be reduced, sometimes greatly.
What this means in terms of output is you may have a larger view of an object with the digital zoom, but chances are your image will become unfocused. Details will become lost. It is actually best to turn off the digital zoom feature of your camera if possible. This will prevent you automatically zooming in too close as the digital zoom is often an extension of the optical.
There are a couple of things you can do if you want a closer view of a subject but want the quality of your picture to still be good. Try moving in closer when you take the picture. Often only a foot or two will do the trick. If this isn’t possible, you can set your camera to take a picture at its highest file size. This will result in a photo that can be cropped to include only your desired subject, yet allow for an image that is still clear.
Digital zoom has its place. It can be used if the only destiny of your photo is the internet. Photos online can be a much lower quality in the camera and still appear acceptable when sent through e-mail or posted on a web gallery. If your goal is printing, however, seek a camera that has a greater optical zoom and turn off the digital zoom. Your pictures will be better in the end, even if they are not as close up.