Biotar 1.8/7.5 cm Lens, c. 1924

Carl Zeiss Jena. No. 625119, in Zeiss VII mount (with the standard tube height of 35 mm), with original unengraved iris diaphragm, unused, optics clean when viewed under point light, all lens elements can be unscrewed. - Note: The lens has eight spaced transitions. At the front is a single lens of 44 mm diameter close to the iris diaphragm; behind it in the rear section in an unthreaded tube of 42 mm diameter are two thin individual lenses with spacer; behind these is a thick triple-lens cemented lens block with an end surface of 38 mm diameter, held in placed by a single thread. Image illumination is well over 85 mm diameter at open stop and infinity. In a test with the lens mounted plane-parallel on a 6 x 6 SLR, the image appeared well illuminated, without field curvature and noticeable reflections when viewed on the screen without a magnifying glass in the focus range. When tested with a strong magnifying glass inspection and test samples, this resulted in a professionally usable image circle of approximately 50 mm diameter, increasing when dimmed. - An early forerunner and possible competitor with the lens designs by Ludwig Bertele, the 4.5 x 6 cm format may also have been considered here, however the Ermanox lens won the race. The global success of the Sonnar under the later aegis of Zeiss may also have played its role. The inconspicuous, standard-looking engraving is typical for several of the test lenses and prototypes by Zeiss. Literature: Erhard Bertele, "Ludwig J. Bertele, a Pioneer of Geometric Optics", 2019, p. 56: "Even apart from its inherent reflections, the Merté lens produced a very attractive image."

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)