Distortion will appear as ripples in the straight edge as it moves across the field of view. You should see what you're looking for . It seems obvious, but be sure a microscope lets you clearly see the features you want to examine. If the instrument you are testing passes all these tests made with real samples, the instrument will perform well for you. A microscope that works well for inspecting bare boards will likely lack the depth of field needed to inspect populated PCBs.
Some differences boil down to aesthetics.
You may simply like the positions and angles of knobs on one instrument more than those on another, and you may not be able to explain why. There's nothing wrong with choosing a microscope that meets your needs and that you like . C.G. Masi works as a freelance technical journalist. Observing Interference Fringes First-time users of microscopes tend to think that the edge of a sharply focused object seen at the limit of resolution will appear as a slightly soft blur, as if slightly out of focus. In fact, at a microscope's resolution limit, edges start to display interference fringes.