Vertical monocular heads provide a vertical photo tube for attaching a camera; there are no inclined binocular eyepieces. Most Olympus compound microscopes can be fitted with a vertical monocular head. Some people with eyesight problems that make it difficult for them to use the binocular eyepieces prefer to view images on a monitor, using a camera on a vertical photo tube. There are no lenses, mirrors or prisms in the vertical tube, so photomicrographs may have slightly more contrast than using a trinocular head.
The vertical monocular heads for the BH, BH-2, CH, CH-2, CK2, CK40 and IMT-2 are interchangeable.
For the Olympus BH-2, CH-2, CK2 and CK40 microscopes, the normal vertical monocular head was the cream BH2-PT Vertical Phototube. It has a standard outside diameter of 25 mm so that a PM-ADF eyepiece adapter can be attached to provide a 38 mm circular dovetail. An NFK photo eyepiece is inserted in the dovetail, and a Photomicro Adapter L attaches to the dovetail.

Olympus BH2-PT Vertical Phototube

Olympus OM Eyepiece Adapter PM-ADF
For more information, see:
For the IMT-2, Olympus produced the sturdier IMT2-PT Photo Tube that incorporates the 38 mm circular dovetail. An NFK photo eyepiece is inserted in the dovetail, and a Photomicro Adapter L attaches to the dovetail.

Olympus IMT2-PT Photo Tube
For the BH, CH and IMT microscopes, the grey BH-PT Vertical Phototube has a standard outside diameter of 25 mm so that a PM-ADF eyepiece adapter can be attached to provide a 38 mm circular dovetail. An FK photo eyepiece or NFK photo eyepiece is inserted in the dovetail, and a Photomicro Adapter L attaches to the dovetail.
The only difference between the BH-PT and the BH2-PT seems to be the colour.

Olympus BH-PT Vertical Phototube
For more information, see:
The older E, F, M and N microscopes had a vertical photo tube with the standard outside diameter of 25 mm so that a PM-ADP eyepiece adapter could be attached to provide a 38 mm circular dovetail. A P photo eyepiece is inserted in thedovetail, and a Photomicro Adapter L attaches to the dovetail.

Olympus E, F, M and N vertical monocular head

Olympus OM Eyepiece Adapter PM-ADP
Olympus supplied instruction manuals with its microscopes. Free PDFs of many of the manuals are available from the Olympus microscope documentation page.
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Created 3rd November 2026 — Updated 3rd November 2026
Copyright © 2026 Alan Wood