Mitutoyo Objective Adapter
The Mitutoyo adapter with M26x36 TPI fits their long working distance objectives.
The PSM will work with any bright field infinity corrected objective designed for use with no cover glass. For very long working distances, a singlet plano convex lens mounted on an Edmund or Thorlabs 1” tube will work just fine. Keep in mind the loss in magnification with increased efl of the objective lens. The tube lens in the PSM has an efl of 100 mm so a 100 mm efl objective will work at 1:1 magnification.