ED glass has been incorporated into selected elements for superior optical performance.

A - "Art Series", large aperture prime lenses, high optical performance.

It shares the same high optical performance as the standard zoom.

Far superior in optical performance, even wide open, from infinity to the close-focus limit at half life size.

This phenomenon is called chromatic dispersion and has important implications for the optical performance of the eye, including the stereoptic effect.

In general, these lenses are well-regarded and have fine optical performance.

This increased optical performance means a higher weight, however (each lens is around 4-5 kilograms).

As a result, optical performance can be improved since there is no extra layer covering the display.

Boasts high optical performance, constant f/4 aperture and versatile 24-120mm focal range.

In overall optical performance, it is nearly impossible to surpass.