The Difference Between Digital And Optical Zoom

Many people who are trying to decide if they should buy and carry a point-and-shoot camera in addition to their smartphone often wonder if there is much in the way of advantage for the camera. This is a topic we have discussed on this blog before. And, as a camera store, we are, predictably, of the opinion that a real camera is much better than a smartphone's built-in camera. We've already covered the fact that the sensor in a dedicated camera will be better and larger than the sensor found in a smartphone camera. However, there is another way in which a point-and-shoot will generally beat out a smartphone camera and that is in the area of zoom. A camera will generally have the ability to do optical or "true" zoom while a smartphone will only be able to do digital zoom. What's the difference? A lot. "True" optical zoom takes place when the lens is extended out of the camera, creating a telescope-like effect that allows the camera to narrow its focus. This also creates the illusion that the camera is closer to the subject because of the removal of the greater background and periphery as well as the magnification of the focal point. To do this requires that part of the lens be able to move, creating distance between itself and the focusing sensor. Digital zoom is a different beast entirely. Instead of magnifying the subject, digital zoom crops out the surrounding area and enlarges the subject, using a bit of software to color in the empty pixels. To see how this works and why it doesn't give the clear vision that true zoom gives, open up any image on your computer in your image editor of choice and "zoom" in a few times. You're not seeing clearer detail -- you're seeing pixels. The same process happens with digital zoom -- you don't get a sharper image with a tighter focus, you get an enlarged version with guesstimated coloring. The details won't be clearer as they are with a camera -- the focus will just be larger. Why don't smartphones offer true zoom? For the same reason they don't offer many other features you'll see on a camera -- space. Smartphone cameras are good for complete novices or for getting a quick picture when you don't care if the quality is very good or not. However, for anyone who cares about how their photos look, the smartphone camera is no substitute for a real camera. -- da Bird