Selection of Components
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A complete system consists of a lens,
an adjusting helical focus mount,
a camera adapter
and possibly one or
more extension tubes.
As a rule, the magnification ß’, defined as the negative ratio
of image size to object size, and the object-to-image distance OO’, the distance
between the object and the sensor/film, are specified by the imaging task. Consult this
chart for more information.
For enlarged images (ߒ=-1...-5) it is recommended that the lens is used in its reversed position;
that is with the front mounted toward the camera. Please keep this chart in mind.
Based on these charts, a lens can be selected that has a suitable object-to-image distance for the
required magnification. The flange-to-image distance (the distance of the mounting surface of
the lens from the sensor/film) needed for selecting required extension tubes, is obtained by
extending a perpendicular line upward on the current image scale and reading the value on the
measurement line of the selected lens.
This value is made up of the flange-to-image distance of the camera (the distance of the sensor/film
from the mounting surface of the camera) and the individual lengths of the camera adapter,
helical mount and any possibly needed extension tubes. In order to have reserve focus adjustment
available, the calculation should start out from a helical mount in mid position
(23.4 mm with +/-6 mm of focus travel).
The length of the extension tube is therefore obtained by deducting the known flange-to-image
distance of the camera, the length of the adapter, and the average length of the helical mount from
the flange-to-image distance.
Contact our sales engineers for help designing your system.
Download the Macro System Brochure.
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