This is The Meyer&Gorlitz PRIMOPLAN 58mm f/1.9. Chapter 17.

This is the second chapter of four for this series of "soap-bubbles" producers, The Meyer Optiks. This chapter is all about the Meyer lenses before the M42 mount. 這是“肥皂泡”製作人 The Meyer Optiks 系列的四章中的第二章。 本章都是關於M42卡口時代之前的Meyer鏡頭。 Music: "23 Chills" from Chillcarrier.de‪@orangesounds3486‬ Sources:commons.wikimedia.org; lensbeam.com; wikipedia.org; pencilofrays.com holmarc.com/meniscus_lenses Graphics of "Development of the Double Gauss Lens" By Paul1513 at en.Wikipedia, CC