User`s manual

Biaxial Displacement Follower User’s Manual Version 1.4, April 19, 2004 IM1013
Page
6
The Lenses
Lens Systems
To accommodate the working distances and measurement ranges that individual applications may require, the standard lens
set supplied is appropriate for a variety of situations. Included in the set are a 105mm enlarging lens, a 50mm variable-focus
camera lens, and five different extension tubes.
The 105mm lens is capable of focusing at fourteen unique working distances and corresponding measurement ranges
depending upon how it is assembled on the tracking head with the possible combinations of extension tubes. The 50mm
lens, used with the same extensions, can focus at an infinite number of working distances and corresponding ranges of
measurement.
If the standard lens set cannot meet an application’s requirements, DE can supply alternative lens systems to meet almost
any standards. Feel free to consult the factory for assistance in selecting an appropriate system.
In determining the measurement range and working distance for the 105 mm lens in varying configurations with the
extension tubes and the 105mm lens, refer to Figure4 and the Standard Lens Sheet on page 22. Keep in mind that the total
displacement that the tracker is to follow should be comparable to the full scale measurement range for the chosen lens
system.
Figure 4
Lens Calculations
A few simple calculations will determine the proper extension barrel and working distance associated with a particular full-
scale measurement range. Please note that these calculations yield theoretical results which will differ slightly from those
obtained in actual practice.