Check the listing for details. Infinity Long Working Distance Plan Objective Lens for Metallographic Microscope. Condition: New. Listed at 37.99 USD. Description: 45mm Focal Plane Infinity Long Working Distance Metallographic Microscope Objective Lens Multi-Coated RMS Thread Plan Achromatic Objectives Connecting thread: international standard interface "4/5 inch * 1/36 inch", diameter M20.2*0.706MM The external thread has a diameter of 20.2 mm and a pitch of 0.706 mm. The lens diameter is 200mm, which can replace imported microscope objective, high-definition imaging, long working distance. Type of screw thread: Standard RMS (20.2x0.706) Magnification NA WD(mm) Focus(mm) Resolution(mm) DF(mm) Object field of view(mm) Image field of view（mm)） 5X 0.12 23.6 36 2.8 42.9 5 22.5 10X 0.25 17.8 18 1.34 10.1 2.5 22.5 20X 0.4 10.4 9 0.8 3.5 1.25 22.5 50X 0.55 7 3.6 0.61 1.4 0.5 22.5 100X 0.8 3.2 1.8 0.41 0.6 0.25 22.5