Two metallographic microscopes can look almost identical from the outside and differ in price by a factor of four. The difference is almost never the body — it is the optics, the illumination path and the stage. Understanding which of those you are paying for is the difference between buying the right instrument and buying a specification you will never use.
Objectives are the most expensive part of a microscope, and their correction class drives the price:
| Class | What it corrects | Cost impact | When it matters |
|---|---|---|---|
| Achromat | Two wavelengths | Baseline | Routine structure checks at moderate magnification |
| Plan achromat | Two wavelengths + field flatness | +30 – 50% | Photography, measurement across the field |
| Semi-apochromat | Three wavelengths + flat field | +80 – 150% | Colour fidelity, fine inclusions, coating interfaces |
| Apochromat | Four wavelengths, highest NA | +200% or more | Research, fluorescence, critical dimension work |
The practical test: if you photograph the field and the corners are blurry, you need plan correction. If colours fringe at high magnification, you need apochromatic correction. If neither bothers you, an achromat is not a compromise — it is the right purchase.
A four-objective turret (5×, 10×, 20×, 50×) is standard. Adding 100× adds cost both for the objective and because a 100× dry or oil objective demands a better stage and a sturdier stand. A coded nosepiece — which reports the magnification to the software and switches the calibration automatically — adds cost but removes a whole class of measurement errors.
| Configuration | Relative cost | Adds |
|---|---|---|
| Halogen, brightfield only | Baseline | Continuous spectrum, good colour rendition |
| LED, brightfield only | Similar | Stable colour temperature, long life, dimmable |
| LED + darkfield | +25 – 40% | Particles, scratches, voids, edge defects |
| LED + darkfield + polarised | +40 – 60% | Anisotropic phases, coatings, stress |
| Above + DIC | +80 – 120% | Surface topography, step height |
Darkfield is the single most cost-effective upgrade for inspection work. It is also the one most often skipped, because on a shiny polished sample it looks like nothing has changed until you find the first particle that brightfield missed.
Stage size is a proxy for what the instrument can hold. A 75 × 50 mm travel stage handles mounted specimens. A 150 × 100 mm stage handles PCB sections and small assemblies. A 210 × 210 mm stage handles a full 200 mm wafer. Each step roughly adds cost, and an inverted configuration — which opens the stage area but complicates the optics — adds more.
A 12 MP USB 3.0 camera with measurement software typically adds a modest amount to the package. A cooled camera for low-light work, or a 4K HDMI camera for PC-free operation, adds considerably more. Software is where the value concentrates: measurement, grain size, coating thickness, report generation and audit trails are what turn images into records.
| Level | Optics | Illumination | Typical use |
|---|---|---|---|
| Entry | Achromat, 3 – 4 objectives | Halogen brightfield | Teaching, incoming visual inspection |
| Standard | Plan achromat, 4 objectives, 75 × 50 stage | LED brightfield + polarised | Routine metallography, coating checks |
| Research | Semi-apochromat, coded nosepiece, DIC ready | LED brightfield + darkfield + polarised + DIC | Failure analysis, semiconductor, measurement reports |
Send us the sample, the measurement and the sample size, and we will quote a configuration rather than a catalogue number.
Tell us the material, the feature you need to see and the magnification range. We will recommend a microscope and quote it.
