I remember hearing a saying for people in Hollywood: the gross is a dream, ask for a cut of net. In cameras, the idea is “the digital zoom is a lie, ask for the optical.” The amount of zoom is one of the most important digital camera comparisons, and most point-and-shoots will list 2 different zoom values for their cameras, like “3x Optical 5x Digital.” Some of them will tell you this gives the camera a full 15x of zoom, which sounds great. But, there’s a but.
Optical zoom uses the lens to change how much of a scene is hitting your sensor. This means that whether wide or tele, you’re using all of your camera’s megapixels. What digital does is reduce the number of pixels from the edge the camera uses, making it look like you’ve zoomed in farther. So, let’s kick our digital zoom in on that picture, and we’ll get something like below. 
The yellow represents the area of the sensor not being used, and you can see that what’s left does, indeed, look zoomed in on.
This is actually a process called ‘cropping,’ and you can do it just as easily using the software that comes with your camera. What’s the problem with using less pixels? After using digital zoom, or cropping, you’ll have a much smaller picture, as you can see below.
If you try printing the picture on the right, it’ll have to be sized up to be as big as the one on the left, and this’ll make is look fuzzier, less sharp, and less detailed.
If you don’t want to make that sacrifice, but still need more zoom than your optical zoom can give you, some Nikon Coolpix cameras and Canon PowerShot digital cameras (among a few others), have available point and shoot lens adaptors, which will add more zoom to your optical zoom.
So, when you’re deciding what camera to buy this Christmas season, decide how much zoom you need and look for ones that have it stated as “optical.”
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