Zeiss Convertible Anastigmat by Ross, London, c. 1895

Ross was one of the renowned lens makers granted Zeiss' license to produce the convertible Anastigmat developed and patented by Rudolph and later named "Protar-Satz" (Zeiss was at that time not capable of meeting the overwhelming demand alone). The convertible lens consist of a front lens with the readable engravings "Zeiss Patent", "27 ½ in." (focal length) and an illegible lens speed. Furthermore 2 blank rear lenses and 2 rings to be screwed into the rear of the tube. The front sections of the tube carries engravings for front lenses F 7/14 ½ in., F 12,5/23 ½ in. and F 12,5/27 ½ in. Iris diaphragm. In original leather case.

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)