CHAPTER 5 Types of Objectives 37
and not flat. The higher the magnification you’re using, the worse this effect gets.
But how to make an image flat again? Clever optical designers came up with objectives
that are calculated to eliminate the field curvature. You get a flat image,
sharp to the edges. Such objectives are indicated by the word »plan« or »planar«.
Flatness of an image is particularly important in reflected light applications. All
objectives for reflected light work (Epi objectives) are flat-field corrected all the
way to the edge.
Markings on the Objective that Reveal
Secrets
There is a lot of written stuff or otherwise visualized information on an objective
lens. Just like a short user manual – so let’s have a quick look at what you can get
from this (Figure 5.1).
Figure 5.1: What objectives can tell you
