Zoom can be described as to close in on your subject. In a camera, it can be achieved in mainly three different ways.
The first one is the basic one, which involves the photographer moving close to the subject.
The second type of zoom is what we are going to talk about here today, optical zoom. It is when the lens within the barrel actually moves to change the focal length and hence zoom. This change in focal length causes the subject to appear closer or farther away depending on the use. Image quality does not degrade while using optical zoom.
The images below show the use of optical zoom. The viewpoint has not changed, just the focal length has changed from about 55mm to 180/200mm.
The third type is the digital zoom. This is where the camera, using its own algorithms, zooms in on the image. It has the previously captured image to begin with and then works on it. The photo quality degrades and after a certain point, it begins to pixellate.
So, dear readers, if you are buying a new point and shoot camera, it is always the optical zoom that you should pay heed to.
Last time, O was for Overexposure.