Optical microscopes rely on visible light passing through samples and magnify images through lens systems. Their resolution is limited by the diffraction limit of light waves, typically reaching up to 200 nanometers. Electron microscopes, on the other hand, use electron beams as their "light source" and focus them through electromagnetic lenses. Since electron wavelengths are much shorter than visible light, their resolution can reach nanometer or even sub-nanometer levels. This fundamental difference in principles defines their completely different application boundaries.

Optical microscopes are like "all-rounders," particularly suitable for observing live cells and conducting fluorescence labeling experiments. Their advantages include simple sample preparation, user-friendly operation, color imaging capability, and the ability to maintain sample viability. Electron microscopes, meanwhile, act as "professional analysts," operating in high-vacuum environments with specially prepared samples. Their extraordinary resolution can reveal ultrastructural details such as viral structures and material crystal morphologies.

The choice between microscope types should be based on three core considerations: observation target scale, sample characteristics, and budget range. Optical microscopes are sufficient for observing micrometer-scale structures like organelles and bacteria, while electron microscopes are necessary for studying nanometer-scale targets like viruses and protein complexes. For live cell samples or dynamic observations, optical microscopes are the only viable option, while electron microscopes provide deeper insights into materials like metals and nanoparticles.

Optical microscopes have relatively lower acquisition costs and simple maintenance requirements, making them affordable for most laboratories. Electron microscopes not only involve expensive equipment but also require specialized sample preparation devices and professional operators, resulting in higher operational costs. Therefore, selection should consider not only initial investment but also long-term maintenance and personnel training expenses.