Heyde Photogrammetric Camera for Alpine Regions, 1926 onwards

Gustav Heyde GmbH, Dresden – Aerotopograph GmbH, Dresden, for Optikon AG, Zurich. Robust photogrammetric camera no. 8902 based on an aerial camera, for 13 x 18 cm plates, exceptional lens by Carl Zeiss Jena with the Double Protar 6.3/26 cm consisting of Protarlinse 480 mm no. 317585 and Protarlinse 480 mm no. 317xxx with yellow filter in a special mount, glass clean under point light, compound shutter is open and non-functional, the camera has the usual Protar aperture scale in millimeters. After inserting a cassette into the back and removing the slide, pressing the side locking levers causes the entire inner measuring mark frame block (inner format 115 x 166 mm) to spring against the photographic plate (for photogrammetry, there were negative plates with optically flat surfaces). The reseau-markings are centrally positioned, each perforated with R (right), L (left), V (front), and H (back). Shutter release (non-functional) is achieved by operating a lever on the right handgrip. Includes focusing screen back. – Note: The Double Protar was the only lens that, thanks to its mere four glass-air surfaces, was free of stray light and virtually distortion-free for this angle of view, even under the most challenging lighting conditions in the changing light of high mountains. The camera was intended for alpine expeditions; the mounting points for elevation suspension are located on the side of the camera, their angles had to be noted manually. Includes transport case. This is the only known measuring camera with the Double Protar lens.

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)