Olympus CX23 Review
Posted: Sat Mar 18, 2023 4:50 pm
I’ve got on my work bench an Olympus CX23 microscope. This is a current model, positioned as an educational microscope for schools and colleges. I decided to compare it to a laboratory-grade microscope (BX40) and see what you would sacrifice if you opted for a CX23 instead.
Probably the first thing you’d notice is how light this microscope is – specs say about 6kg / 13lb. It feels like a half of BX40. The internal aluminum-alloy frame is covered by plastic panels, and they are a bit creaky when you press on them hard. The upper frame is divided into two arms, this reminded me of a classic Steindorff Microbe Hunter https://www.microscopy-uk.org.uk/mag/ar ... dorff.html (I’d love to own one someday!). Being a “school” microscope, the 10x/20mm eyepieces and the 30° head are locked with additional screws, they require just a couple of turns to release. The four Plan Achromat objectives (4X, 10X, 40X, and 100X Oil) with F.N. 20mm are just set really tight in the nosepiece, no thread locker is used. I was able to unscrew them with a silicone pad with no problems and no marks left. Note how the inner optical elements of the 4X and 100X objectives protrude well beyond the objective thread into the nosepiece. This makes them unusable in other Olympus microscopes – they stop the revolver’s rotation when installed into BX40.
On the other hand, optics from BX40 – the objectives and the tilt head – fit perfectly in the CX23 and perform normally – the head dovetail is the same, and the air inside the two Olympus microscopes seems to be identical
CX23 uses an LED light source, and, for student’s safety (my guess), its max. brightness is limited but sufficient for transparent specimen observation. The LED has a visible magenta tint when viewed from outside, but it is not very noticeable when looking through the optics.
This microscope uses a simple Abbe 1.25 condenser, its height can be adjusted by a knob, and a variable aperture lever has markings at 4, 10, 40 and 100x positions. Olympus makes a kit containing a field diaphragm and a condenser centering lens https://www.olympus-lifescience.com/en/ ... ontent6318 to add Kohler illumination, if desired. Does anybody know where I can buy this kit in the USA, or has one for sale? I think the kits from older models (CH and CX series) would fit also – my filter holder from the old CH2 fits perfectly into this condenser. I tried to hand-hold the condenser from the BX40 under the stage, it fits fine and provides better contrast, but mounting it will require a 3d-printed adapter, as this condenser is mounted to the condenser carrier using 3 screws, not a dovetail.
The mechanical stage is rack-less, it uses wire to drive the specimen holder, its movement is precise and without any backlash.
I was pleasantly surprised how well the optics performs in this microscope – the 4x, 10x, and 40x (I did not test the 100x) Plan objectives create evenly lit, sharp image from edge to edge, without any hint of softness at the edges, and minimal chromatic aberration on par with Olympus BX40 Plan objectives – in fact, when the 22mm eyepieces from BX40 are installed in the CX23, the image remains sharp to the edge!
The small power brick can be inserted into the base, so only the power entry connector is accessible, so you can use it as a regular, brick-less microscope, if desired.
What I liked:
- Lightweight
- Small footprint
- Great ergonomics
- I find it good looking, but it’s in the eye of the beholder, I guess
- Great optical performance
- Condenser is height-adjustable, has a diaphragm.
- Rack-less, precise mechanical stage
- Compatible with Olympus UIS/UIS2 optics (upgradeable)
What I did not like that much:
- Plastic panels are a bit creaky
- Frame and stage are not as sturdy as BX40, but this is expected (not flimsy in any way)
- LED has some magenta tint, limited max. brightness.
- Uses an external power brick (but small and hides in the base)
- Condenser is very basic, upgrading will require custom parts.
- Kohler illumination is not included (kit is available, but is difficult to find).
Why am I looking at microscopes like CX23? The work bench you see in the top photo is my electronic bench where I work on my electronics projects. I don’t have a dedicated place to use a microscope when I feel like it, so I have to bring the microscope from the closet to this bench. I have some back problems, and carrying something like BX40 I have now is difficult. I am in search for a “no optical compromise” lightweight microscope, I am not sure yet if this CX23 is the ticket… any ideas will be appreciated.
Probably the first thing you’d notice is how light this microscope is – specs say about 6kg / 13lb. It feels like a half of BX40. The internal aluminum-alloy frame is covered by plastic panels, and they are a bit creaky when you press on them hard. The upper frame is divided into two arms, this reminded me of a classic Steindorff Microbe Hunter https://www.microscopy-uk.org.uk/mag/ar ... dorff.html (I’d love to own one someday!). Being a “school” microscope, the 10x/20mm eyepieces and the 30° head are locked with additional screws, they require just a couple of turns to release. The four Plan Achromat objectives (4X, 10X, 40X, and 100X Oil) with F.N. 20mm are just set really tight in the nosepiece, no thread locker is used. I was able to unscrew them with a silicone pad with no problems and no marks left. Note how the inner optical elements of the 4X and 100X objectives protrude well beyond the objective thread into the nosepiece. This makes them unusable in other Olympus microscopes – they stop the revolver’s rotation when installed into BX40.
On the other hand, optics from BX40 – the objectives and the tilt head – fit perfectly in the CX23 and perform normally – the head dovetail is the same, and the air inside the two Olympus microscopes seems to be identical
CX23 uses an LED light source, and, for student’s safety (my guess), its max. brightness is limited but sufficient for transparent specimen observation. The LED has a visible magenta tint when viewed from outside, but it is not very noticeable when looking through the optics.
This microscope uses a simple Abbe 1.25 condenser, its height can be adjusted by a knob, and a variable aperture lever has markings at 4, 10, 40 and 100x positions. Olympus makes a kit containing a field diaphragm and a condenser centering lens https://www.olympus-lifescience.com/en/ ... ontent6318 to add Kohler illumination, if desired. Does anybody know where I can buy this kit in the USA, or has one for sale? I think the kits from older models (CH and CX series) would fit also – my filter holder from the old CH2 fits perfectly into this condenser. I tried to hand-hold the condenser from the BX40 under the stage, it fits fine and provides better contrast, but mounting it will require a 3d-printed adapter, as this condenser is mounted to the condenser carrier using 3 screws, not a dovetail.
The mechanical stage is rack-less, it uses wire to drive the specimen holder, its movement is precise and without any backlash.
I was pleasantly surprised how well the optics performs in this microscope – the 4x, 10x, and 40x (I did not test the 100x) Plan objectives create evenly lit, sharp image from edge to edge, without any hint of softness at the edges, and minimal chromatic aberration on par with Olympus BX40 Plan objectives – in fact, when the 22mm eyepieces from BX40 are installed in the CX23, the image remains sharp to the edge!
The small power brick can be inserted into the base, so only the power entry connector is accessible, so you can use it as a regular, brick-less microscope, if desired.
What I liked:
- Lightweight
- Small footprint
- Great ergonomics
- I find it good looking, but it’s in the eye of the beholder, I guess
- Great optical performance
- Condenser is height-adjustable, has a diaphragm.
- Rack-less, precise mechanical stage
- Compatible with Olympus UIS/UIS2 optics (upgradeable)
What I did not like that much:
- Plastic panels are a bit creaky
- Frame and stage are not as sturdy as BX40, but this is expected (not flimsy in any way)
- LED has some magenta tint, limited max. brightness.
- Uses an external power brick (but small and hides in the base)
- Condenser is very basic, upgrading will require custom parts.
- Kohler illumination is not included (kit is available, but is difficult to find).
Why am I looking at microscopes like CX23? The work bench you see in the top photo is my electronic bench where I work on my electronics projects. I don’t have a dedicated place to use a microscope when I feel like it, so I have to bring the microscope from the closet to this bench. I have some back problems, and carrying something like BX40 I have now is difficult. I am in search for a “no optical compromise” lightweight microscope, I am not sure yet if this CX23 is the ticket… any ideas will be appreciated.