This is The Meyer&Gorlitz PRIMOPLAN 75mm f/1.9. Chapter 18.

This is the third chapter of four for this series of "soap-bubbles" producers, the Meyer Optiks. This chapter explains M42 lenses "Cooke Triplet" & "aberration". 這是“肥皂泡”製作人 The Meyer Optiks 系列的四章中的第三章。 本章介紹 M42 鏡頭“Cooke Triplet”和“像差”。 Music: Untold Words‪@FPMMUSIC‬ Sources:commons.wikimedia.org; lensbeam.com; wikipedia.org; pencilofrays.com Graphics of "Development of the Double Gauss Lens" By Paul1513 at en.Wikipedia, CC