Français Giant Brass Lens, 1881

Français, Paris. No. 5118, for multiple focal length, brass tube for waterhouse stops, with extension tube. 1) Petzval front lens, glass (F = approx. 110 cm) clean and well, glass diameter approx. 132 mm, glass signed "Français 1881", holder sticks, inside lens some slack, probably inside the usual paper for justage missing. (3/3) - 2) Petzval back part, mount with other thread, only 2 turns usable, on negative lens signed "6-5 pouces F-AG + (?) AG". Good pictures with approx. 4,5/60 cm. (All f-measurement infinity as distance from aperture-slot) Last lens outside with rotations-symmetrical scratches. Height with sunshade 36 cm. (3-/3-4) - 3) Petzval back, inside on metal signed with pencil "Laverne", correct thread. For approx. 5,4/70 cm. On glass border brocken parts, up to 14 mm (when hidden with cover, then there is a clean diameter of 103 mm). Inside holder sticks, about that uncleaned and picture quality therefore not tested. Height with extension tube and sunshade 46 cm. Weigth approx. 7,5 kg. (4/-) - 4) Petzval front lens from another giant lens, sun-shade on it sticks. Multiple usable, as A), because no original thread, provisional mount with one turn on tube as a kind of aplanatic system of approx. 4,5/58 cm, thanks to only 4 glass-air surfaces brillant pictures. A notice - the first portrait lenses, as Geiger in Stuttgart 1839, were constructed from 2 telescope achromats in very long distance. Or usable as B) high-speed combination, because it can be provisionally mounted on the Petzval back of the 4,5/60 cm (!) with a resulting F = approx. 3,6/480 mm. On infinity is a plane pictures size of over 30 cm diameter. (3-/3-) - High-tech from yesterday, it made possible a maximum of speed for studio collodium photography. The corresponding original camera is in our auction. See Lot no. 274.

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)