Par-Focalizing The Zoom System - Navitar 12X Zoom Instruction Manual

Navitar Motorized Zoom Systems Instruction Manual for Windows
9

Par-focalizing the Zoom System.

All Navitar Zoom Systems are designed to be parfocal (maintain focus as they
change magnification), but they must be setup in a prescribed manner.
The rule of thumb is "set the front conjugate (distance from lens to object) at high
mag, and the rear conjugate (distance from lens to image plane) at low mag."
Note: If an integral focus is present on the zoom lens, set if halfway between
extremes of travel.
1. Zoom to the highest magnification.
2. Adjust the stand, or other support, to provide a rough focus, and then fine tune
it with the integral focus, if present.
3. Zoom to the lowest magnification.
4. Without disturbing any adjustments made in #2, adjust the upper adapter to
produce best focus at the image plane.
The system should now zoom between extremes without losing focus.
Revision B Page 16 of 23 2/17/2004