Eyepiece magnification (left: with naked eye, right with magnifying glass)<br><i>h</i> = object height; <i>v</i><sub>1</sub>, <i>v</i><sub>2</sub> = object distance; <i>φ</i><sub>1</sub>, <i>φ</i><sub>2</sub> = view angle; <i>f</i> = focal length
<a href="//commons.wikimedia.org/wiki/User:HHahn" title="User:HHahn">HHahn</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>