|
 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 (ß’=-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
an optical engineer for
help designing your system.
Download the Macro
System Brochure. |
