Optical vs. digital zooming. What's the difference, you ask?
Let's just say you asked.
The difference, I would tell you, is that optical zooming accomplishes the zoom using adjustments to the lens optics, enlarging the image projected on to your camera's sensor. Digital zooming is essentially a crop of the sensor image. In other words, an optical zoom is far superior, and is really the only kind of zooming you should do.
Current phone-based cameras support only digital zooming, and that's why you should never zoom with your phone.
Why am I telling you all of this?
Because this week, I decided to digitally zoom a previous image of mine. But it's ok, I know what I'm doing.
Let's just say you believe that.
Anyway, about a month ago, I posted an image of daffodils. There were two daffodils in the shot, and I decided to "zoom" in by cropping the photo such that the foreground flower fills the frame. I also emphasized the flower's color and de-emphasized the background color. Here's how it turned out:
The danger of a "digital" zoom like this is that you're throwing away pixels. The loss of resolution can sometimes lead to a problem. But it was ok in this case because the original image had a high resolution (3572x2858). After cropping, the photo above still has a resolution of 2206x1471, which is still big enough to produce a good quality image at a decent size.
The moral of the story is that digital zooming is to be avoided, unless you have the pixels to allow it.
And, now you finally know the reasons why.
Let's just say you've been wondering.