A simple lens consists of a single optical element.

This too can be cancelled by including a third curved optical element.

To design optical elements, several algorithms are used to shape scattered radiation patterns.

This has the effect of keeping the optical elements parallel to each other.

Some designs for large telescopes use whippletrees, to support the optical elements.

There is no need for other optical elements to focus light behind a reticle.

Every part of a mirror or lens produces the same image as the whole optical element.

Infinity focus would be lost with an adapter which lacks optical elements.

This time the optical element was a globe cut in half, with black concentric circles painted on it.

And, all that power has an effect on those optical elements.