Olympus BX50 Polarizing Microscope – Geologist’s Guide
Read the edited video transcript for ‘Olympus BX50 Polarizing Microscope – Geologist’s Guide’
Hey, this is Chad with Munday Scientific and Microscope Marketplace. Today, we’re going to talk about this Olympus BX50 polarizing microscope. We just sold this scope, and it’s headed out to New Mexico. We’ll go over how to take it apart, put it back together, and highlight a few features that may help the end user.
As usual, Michael is going to join me, and we’ll get started.
Built-In Tool and Viewing Head Light Path
All BX-series microscopes include a built-in 3 mm Allen wrench, which is an incredibly handy tool and works on almost the entire microscope.
This scope is equipped with a trinocular viewing head. The pull rod controls how light is distributed:
- All the way in: 100% of the light goes to the eyepieces
- Middle position: Light is split between the eyepieces and the camera
- All the way out: 100% of the light goes to the camera adapter
Camera Adapter and Focus Adjustment
Let’s talk about the camera adapter and how to remove it. Mike, come in here and show this. The camera adapter is secured with a 3 mm Allen screw. Once loosened, the adapter can be removed.
This is an Optimum 0.5x camera adapter. The adjustment wheel moves the internal focal lens. This is important because the image seen through the eyepieces may not match what appears on the camera. To adjust it, first focus the specimen through the eyepieces. Then, with the camera attached, rotate the adjustment wheel while watching the screen until the camera image comes into focus.
If you need help with this, feel free to reach out—we’re happy to walk you through it, and we also have additional videos that cover this process.
Eyepieces and Diopter Adjustment
This microscope has one fixed eyepiece and one focusable eyepiece. The fixed eyepiece is adjusted using the diopter tube. We recommend aligning the zero mark with the white dot as a starting point.
The focusable eyepiece is especially important on a polarizing microscope because most users want a crosshair in one eyepiece. You can bring the crosshair into and out of focus by rotating the eyepiece. A small alignment pin fits into a slot, allowing you to rotate it easily with one hand.
Removing the Head and Bertrand Lens Assembly
To remove the head, insert the 3 mm Allen wrench into this access hole. Mike, show that here. Once removed, you’ll see the Bertrand lens assembly.
This setup is slightly different from the conoscopic lenses we typically show, such as the U-CAP. This system uses a U-PA configuration.
Analyzer and Wave Plate
The microscope includes a Bertrand lens and a rotating analyzer that turns 180 degrees and can be pulled in and out. There is also a dedicated slot for a wave plate. This customer requested a TP530 nanometer wave plate, which has already been installed.
We’ve centered the Bertrand lens ahead of time, so when the customer receives the scope, they’ll only need to install it and center the stage using the 10x objective.
Objectives and Centerable Nosepiece
This microscope features a centerable nosepiece and uses the same 3 mm Allen wrench. Always lower the stage before removing the nosepiece.
The scope includes 10x, 20x, and 40x objectives, and the customer will also receive a 4x objective. Each objective can be centered individually, but we’ve already completed this step. Once the nosepiece and stage are reinstalled, the user simply needs to center the stage to the 10x objective, and the scope is ready for use.
Condenser Removal and Features
Next, let’s talk about the condenser. Raise the stage, lower the condenser using the circular knobs on each side, and loosen the knurled thumb screw to remove it.
This is a U-PC2 flip-top condenser. It includes a polarizer on the bottom, which can typically be locked in place. There’s also an aperture diaphragm that allows you to adjust contrast. If you ever use a 2x objective, you can flip the top element out. For most objectives, the top element should remain in for optimal image quality.
Reinstalling the Condenser and Illumination Setup
When reinstalling the condenser, align the small pin with the groove in the back. Insert it slightly at an angle, rotate it until it slides into place, and lock it in.
The two adjustment screws are used to set Köhler illumination, which we cover in another video.
Above the condenser, you’ll find the field diaphragm, daylight blue filter, and neutral density filters (ND6 and ND25). These filters allow you to control color temperature and light intensity.
Stage, Slide Holder, and Centering
This microscope is equipped with a U-FMP slide holder. You can remove it by rotating the two release knobs. If you don’t want to use a slide holder at all, you can remove it entirely using the 3 mm Allen wrench.
If stage centering is needed, it can be done using the two centering screws located here. The stage also features a click stop, which helps locate the center position. The click stop can be adjusted here.
Reassembly Process
To reassemble the microscope, lower the stage, slide the nosepiece back into place, reinstall the slide holder if desired, and put the head back on. The flange slides underneath, and everything is secured with the 3 mm Allen wrench.
If you ever need to center the objectives, use a 1.5 mm Allen wrench. Insert it into the adjustment points on each side of the objective to fine-tune alignment.
Power Controls and Light Preset
The power switch is located here. Once the microscope is on, the rheostat controls the light intensity. There is also a preset button—if this button is pressed, the brightness knob will not function.
If needed, you can still adjust the light by inserting a flathead screwdriver into the preset adjustment. If the light won’t change, this preset button is usually the reason.
Bulb Replacement
Always unplug the microscope before changing the bulb. Insert the Allen wrench here to loosen the screw and remove the cover. This microscope conveniently includes a diagram on the back showing the bulb replacement process.
Slide the lamphouse off, loosen the top screw using the same Allen wrench, and remove the housing. Inside is a 12-volt, 100-watt bulb. We include extra bulbs and a dust cover with the scope.
Press the two retaining prongs down and lift the bulb out. Do not touch the new bulb—use the wrapper, a tissue, or a Kimwipe. Insert the new bulb, release the prongs, and ensure it is secure.
Reassemble the lamphouse, apply slight pressure to overcome the internal spring, tighten the screw, plug the scope back in, and you’re ready to go.
Intended Use and Closing
This microscope will primarily be used for geology work. If you have any questions about this scope or any other microscope we sell at Microscope Marketplace and Munday Scientific, give us a call at 919-775-5596 or email us at —Munday with a “U,” singular, not plural.
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