Very Early Brass Petzval-Type Lens by Dörffel, Berlin, c. 1841-4

Dörffel, Berlin. Brass mount with rack-and-pinion focusing (working), threaded elements, brass front cap inside with an handwritten note about a price, height of the lens with lens hood 15,5 cm, diameter lens hood 8 cm, diameter of the front achromat 51 mm (approx. 4/20 cm), glass clean. References: D’Agostini, "Photographic Lenses in 19th Century Germany and Austria" 2016, p. 19, for reference to Cornwall’s "The history of photography in Berlin 1839-1900": "… the optician Carl Theodor Dörffel (1810-1878) in Berlin was the first in Germany who built and sold German cameras. On 16. September 1839 he presented his first camera in his sales room at Unter den Linden 46 and took orders." (translation from the German original) - A rare lens by the first commercial German camera maker (and probably a lens maker too), the only known example.

布雷克拍品等级是为了方便竞买人判断拍卖品的成色而设置的。布雷克等级用1到6级来标注外观和功能的成色，(从非常好到非常差)。 在目录图册里用括号里的2个数字来表示，前一个数字表示外观成色的级别，后一个数字表示功能成色的级别。如(3/2)表示外观成色是3(满意的)，功能成色2(好)。 成色 定义参照下列标准： 1 - 非常好 (未使用过，没有使用痕迹) 2 - 好 (新，极少的使用痕迹) 3 - 满意的 (普通的使用痕迹) 4 - 及格的 (明显的使用痕迹，某个非主要部件是后配的) 5 - 有缺陷的 (极明显的使用痕迹, 某个主要部件是后配的，功能上有缺陷，需要修理) 6 - 非常差 (严重破损, 缺少重要部件)