‘Project Beater’ – my Olympus BHB microscope rebuild is progressing nicely. The list of issues with it continues to be worked through. After sourcing a new fuse, I discovered that the electrics are fried. Rather than fixing 40 year old electrics to power the light source I decided to modify the light to LED instead. The original bulbs were 6V and 30W, and were soldered into a special mount.

As my bulb was broken, I cut it out from the mount, and attached a 3W 6500K daylight LED on the bulb base in its place.

This LED bulb could be powered from the bench top power supply I have, so I connected it up, and yes, we have light!!!

Next, how to attach a camera. The microscope is trinocular, with a camera port on the top. I sourced an Olympus 3.3x NFK photo eyepiece, and an old Nikon F Mount to microscope adapter, and they fitted straight on, giving me about 20x magnification (about 2x my eyepieces).

For a camera I fitted my monochrome converted Nikon d850. As I’m planning on doing mainly black and white images, this is the ideal camera for it, as it has a moveable LCD screen on the back, and electronic first curtain shutter. The setup is almost parfocal between the eyepieces and the camera, requiring only a small amount of refocusing.

With the slide prep kit I got, there were a few mounted specimens. Here’s a shot of the Mosquito larvae, taken with the 4x Olympus SPLan objective (overall magnification about 80x).

Given I’ve not really setup the light properly yet, this is encouraging. Next steps. I’ll probably rebuild the LED light source a little differently. The LED is not in the same position as the filament from the bulb would have been, which could be impacting how its focusing through the microscope. I also need to make sure its properly aligned. I have a green LED bulb, which I may make into a light source. As that would be a more monochromatic light source, I should get slightly sharper images due to reduced chromatic aberration. The photo eyepiece is a bit strong, so I may try and find a lower power one.

It’s been a fun build so far, and I’ve learned quite a lot about how microscopes work. More work to come, but for now, time for a coffee…..