
Here's a little demo for you to show how far away I was from the eagles the other day. The overall picture was shot with the camera zoom set at it's shortest length of 75mm. The small rectangle near the center that's slightly brighter blue is with the lens set at 300mm. This is what most camera makers refer to as optical zoom.

Above you can see the full picture at 300mm. As you can see, the eagles are stil pretty much dots near the center.

And here is a detail of the picture where you can actually make out the birds. This is an 8 megapixel camera, so there is a lot of detail in there. This would be digital zoom. All I'm doing is cropping out extraneous information. The picture is smaller, but it's easier to see what you're looking at.

I could go really crazy and zoom in on just one of the birds if I want, but the picture quality is getting really poor.

You can take the digital zoom to it's logical limit, if you'd like, but pretty soon all you can see are the zeroes and ones that lie behind the digital data.