Objective

An objective, or infinity corrected objective, may be used as a "taking lens" for an ultra version of the Zoom 6000, 12X, or Precise Eye.

If a coax illuminator is used, it is better to incorporate incident light objectives. Incident light objectives are coated to produce less back reflections.

With coax, some vignetting will occur if the system is working the objective below it's normal field of view (less than 1X+ on the zoom setting).

The stated objective mag is only accurate when using a rear tube lens (decollimating lens) of the proper focal length, usually 200mm. As the focal length of the zoom varies with mag, the effective mag of the objective will vary.

A similar phenomenon occurs with the stated NA of the objective. A certain zoom setting must be reached before the full NA may be utilized.

Navitar has a selection of thread adapters which permit coupling of common objectives to the lower end of their "ultra" lens systems.