Cardinal point (optics)

Okay kiddo, so you know how when you look through a camera or a pair of binoculars, things look closer or farther away depending on how you adjust the lens? Well, there are some special points called cardinal points that help with this process.

The first cardinal point is called the object distance, and this is where the object you want to see is located. Then there's the first focal point, which is where the light from the object is bent by the lens and meets in a point. The second focal point is the same thing, but for the light that's already passed through the lens.

Finally, there's the image distance, which is where the image of the object is formed after it's been magnified by the lens. These cardinal points help the lens focus the light and create a clear image for us to see. Pretty cool, huh?