Table 3976. Comparison between optical and electron microscopes.

	Light/optical microscope	Electron microscope
Probe source	Light source	Electron source
Lenses	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	Yes	No. But stained tissue
Recording media	Eye or photographic film	Phosphor screen or photographic film
Wavelength of probe	> 10 nm	Less than 1 nm
Information delivered by the microscope	Less details	More details
Depth-of-Field (DoF)	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
Maintenance	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.