Olympus BH Identification

Page on identifying BH vs BH2

In general:

• Parts are mechanically compatible
  • I've seen many Frankenstein systems on the surplus market
  • Mixed parts will "mostly work" but give sub-optimal images
• Paint
  • BH: silver paint
    • Illuminator, frame
  • BH2: white or black paint
    • Black paint on low end illuminators (BH2-MA, BH2-RLA)
    • White paint on higher end BH2-ULA
    • White paint on observation tube, base
• Objectives
  • BH: finite
  • BH2: infinity
    • Sometimes Mitutoyo M Plan Apo are also used (with caveats)

Illuminator

Models:

• BH-MA
  • Silver paint
• BH-RLA
  • Silver paint
• BH2-MA: BF
  • Black paint
• BH2-RLA: BF, DF
  • Black paint
  • Vs BH2-MA: has "pull BF" knob
• BH2-UMA
  • White paint
  • High end illuminator
  • Very distinct looking...you won't confuse it with others

Practical information

Designed to do some correction in objective, some in eyepieces

• Ex: "Olympus NeoSPlan" objective + NFK relay lens
  • Ok
• Ex: "Olympus NeoSPlan" objective + touptek relay lens
  • Aberration
• Ex: "Mitutoyo M Plan Apo" objective + touptek relay lens
  • Ok
• Issue: NFK1.67 very expensive for APS-C camera
  • Proposal: use less expensive NFK or eyepiece to do correction and then touptek relay lens for final sizing

BH and BH2 are mechanically but not optically compatible

• Can use turrets interchangeably
  • Ex: use RMS threaded MSPlan on BH2 using BH's turret
• Mixing illuminators will cause aberrations