Comparison between Optical/Light and Electron Microscopes
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Table 3976. Comparison between optical and electron microscopes.
Light/optical microscope
Electron microscope
Probe source
Light source
Electron source
A series of simple curved glass lenses
Electrostatic or electromagnetic lens
Spatial resolution
Under optimal conditions (excellent lenses, oil immersion) the resolution is ~ 200 nm. See page4526
TEM: 0.05 nm; SEM: ~ 1 nm.
Ability of observing living cells to biologists
No. But stained tissue
Recording media
Eye or photographic film
Phosphor screen or photographic film
Wavelength of probe
> 10 nm
Information delivered by the microscope
Less details
More details
Shallower due to the properties of its glass lenses (e.g. DoF is ~1 µm) Deeper because SEM/STEM don't use lenses to directly form images, but they form images by scanning a focused beam from pixel to pixel, e.g. for a working distance of 20 mm, the DoF is ~0.4 mm at 100x, 40 µm at 1,000x and 4 µm at 10,000x
Maximum magnification power
2,000 times
As high as 20,000,000 times (for TEM); as high as 1,000,000 times (for TEM)
Operation condition
Operates at atmospheric pressure Operates under high vacuum to prevent the electron beam from being scattered by gas molecules
Easier to maintain
Not easy
Typical price
$100 or more
More expensive; $100,000 or more
Main problems
Low spatial resolution
Specimens must be fixed in plastic and viewed in a vacuum; specimens can be damaged by the electron beam
Other differences
The oldest (Starting in the 17th century), simplest and most widely-used form of microscopy
Starting in the 20th century
Specimen limitation
Any specimens Gases cannot be analyzed and liquids are limited to those that have very limited volatility and will not contaminate the column and specimen chamber because specimens must be exposed to vacuum conditions.