Incorrect. You're misunderstanding the way the system works. Let's see if I can explain it again less confusingly.

I will preface this by saying that this is a feature only available on some brands and models of camera, not all of them. Conceptually, though, it's quite simple once you understand it.

The 3x zoom lens is not projecting a bigger image onto the sensor. That's the point: It's projecting the same 3x size image onto the full width and height of the sensor.

Let's say the sensor is, I dunno, 1000 pixels wide, just to make the math simple.

Then, to grab the image off the sensor, let's say I only use the middle 640 of those pixels.

Instead of taking the whole image off the whole sensor and downsampling it, I'm still using the 1:1 pixels of the sensor as they already exist.

But because I'm only looking at the cropped middle 640 of those pixels, I'm effectively getting a farther zoom than 3x.

This of course only works if you're deliberately using a lower rez than the sensor is capable of. And of course, you'd get the same result if you'd simply shot at the full rez and then cropped the picture after the fact.

Make sense?