Examples of Investigation and Measurement

Model of camera obscura
A pinhole camera is set up, consisting of a narrow diaphragm and – instead of the classical matt screen – a CCD array connected to a monitor. In this arrangement even dim images are detected and do not need to be observed in a dark room.

Influence of diaphragm size and position
By increasing the size of the diaphragm the brightness increases, but the sharpness of the image becomes worse. By changing the distance between diaphragm and CCD array the magnification of the pinhole camera is varied.

Influence of optics
The use of collimating lenses in front and behind the diaphragm increases the brightness and improves the sharpness dramatically. Several types of objectives can be set up and investigated. A variable diaphragm demonstrates the effect of screening and the changes of the depth of field are observed.

OXP-19 Required Equipment
1	02.0300	Profile rail OCM 650, 300 mm The high precision optical rails are made out of special anodized aluminum. The rails are the base for various modules attached to carriers.
1	02.1024	Carrier OCM 650, 20 mm with attached plate holder Using a spring loaded blade 50 x 50 mm, plates like filters or gratings can be fixed onto this module. The carrier allows the direct attachment to the optical rail. The carrier 20 mm and the holder are made out of special anodized aluminum.
2 2	02.2126 02.2132	Mounting plate OCM 650 for click 25, including carrier 20 mm Mounting plate OCM 650 for click 30, including carrier 20 mm Mounting plates are used to hold optical mounts. A characteristic feature of the mounting plates is the “click” mechanism of the inserts based on spring loaded spheres. Snapping in the groove of the inserted click mount, the optical element is kept in an exact position. On the other hand, the system allows a quick and easy change of the mounted inserts. The mounting plates are made out of special anodized aluminum. Mounted onto the carrier 20 mm, the mounting plates can be placed onto an optical rail.
1	02.2528	Click mount 25 mm with 0,5 mm hole aperture This click mount 25 mm contains a disk with a 0.5 mm hole aperture and is commonly used to reduce the acceptance angle of a photodetector. The click mount can be fixed onto a mounting plate (02.2126).
1	02.2529	Click mount 25 mm with 0,1 mm hole aperture This click mount 25 mm contains a disk with a 1 mm hole aperture and is commonly used to reduce the acceptance angle of a photodetector. The click mount can be fixed onto a mounting plate (02.2126).
1 1 1 1	04.0051 04.0053 04.0060 04.0062	Biconvex lens f=100 mm, mounted in click 30 mount Biconvex lens f=150 mm, mounted in click 30 mount Plano convex lens f=40 mm, mounted in click 30 mount Plano convex lens f=60 mm, mounted in click 30 mount different glass lenses are mounted onto a special anodized aluminum click mount 30 mm by two threaded mounting rings to be used in connection with a mounting plate (02.2132).
1	04.0138	IR block filter, size 50x50x3 This glass filter is used for suppressing IR light coming from a light source. The filter can be fixed onto a plate holder (02.1024). Dim: 50 mm x 50 mm x 3 mm
1	04.0308	Iris aperture mounted in click 25 mount, max. opening 14 mm The continuously adjustable laminar aperture limits the diameter of the beam from 1 mm to a maximum of 14 mm. The iris aperture is mounted onto a special anodized aluminum click mount 25 mm by a threaded mounting ring to be used in connection with a mounting plate (02.2126).
1	09.2930	CCD array with monitor The colour CCD array is fixed in a sleeve mountable onto a click 25 mounting plate 02.2126. It has a power supply and can be connected to 230 VAC / 50 Hz directly. The CCD can be connected to the monitor via a BNC cable. The CRT colour monitor screen has a diameter of 300 mm and is equipped with a BNC input. Further specifications of the camera: Video System: NTSC / PAL Effective pixels: 628 x 582 S/N ratio: more than 48 dB Sync frequency: NTSC 60 Hz / PAL 50 Hz.