Abstract: Optical high-pressure transmission cells of the type used, for example, for SFC-FTIR, comprise a pressure-resistant housing part with two intersecting bores, one of them forming a fluid passage and the other one forming a light transmission path. The bore forming the light transmission path is provided with inserted windows. There is a demand in infrared spectroscopy, for supercritical fluid chromatography, for particularly pressure-resistant cells of simple design, which demand has not been satisfied heretofore. In the case of the proposed measuring cell, the windows are designed as stepped windows having central cylindrical neck portions engaging the bore serving as a light transmission path so that the chamber is delimited by end faces of the neck portions. Sealing is effected by O-rings.

Abstract: A micro-flow cell for chromatographic, spectrometric or scintillation measurements comprises a capillary tube, preferably made of glass or silica glass, through which flows the medium to be examined, and a holding device for said capillary tube. The holding device is separably composed of at least two parts which can be separated in their longitudinal direction. The capillary tube is fixed in the holding device by suitably formed connectors so as to be stress-free and tension-free to the greatest possible extent.

Abstract: A coupling device for attaching frame-shaped accessories to photographic equipment which includes an annular rib (32) projecting in the axial direction with an annular collar projecting radially outwardly that continuously extends over 360.degree. and has conical guide surfaces (33A, 33B) at one axial end surface of a first frame-shaped accessory (20, 60) to be coupled. Another accessory (60, 20) to be coupled has at one axial end surface several supports (65) projecting parallel to the axis which are somewhat elastically flexible in the radial direction, with claws (67) that are pointed radially inwardly. The supports (65) and the claws (67) of one accessory (60) are formed and attached in such a manner that the claws (67) can be connected to the annular collar (33) of the other accessory (20) in a coupling grasp and can be disconnected again from the annular collar (33), whereby the claws (67) glide over the conical guide surfaces (33A or 33B), the supports (65) being somewhat flexible and elastic.

Abstract: A focusing-screen holder (13) provided with a focusing screen (14) is connected to a camera back (11) by means of springs (15). At least one cam plate (17) is located on the focusing-screen holder (13). This cam plate (17) can be swung between two end positions by means of an actuating handle (26) and cooperates with a slide face (22) of the camera back (11). In its first end position, cam plate (17) enables the focusing screen holder (13) to enter into abutting relation with the camera back (11) through the force of the springs (15). By swivelling the cam plate (17) to its second end position, the focusing-screen holder (13) is lifted off the camera back (11) against the force of the springs (15). The cam plate (17) has a radial cam (52) which is in abutting relation with an actuating pin (50). The latter is under the effect of a retarding mechanism (36) so that swivelling motions of the cam plate (17) from the second to the first end position are damped, dependent upon the actual velocity.