In general, seeing tiny objects can be difficult but necessary, especially for scientists working in medicine, forensics, astronomy, and nanotechnology.
To aid in exploring such samples up close, researchers must enlarge them while maintaining complete detail visibility. Since then, powerful instruments have become available, making scientific research much easier.
One of the more prominent examples of these instruments is the microscope. Since it was invented, it has enhanced our sense of sight while allowing us to look directly at objects far too small to see with the naked eye.
Microscopes and other similar instruments accomplish this by making things appear larger (magnifying them) while also increasing the level of detail we can see (which in turn enhanced our ability to “resolve” two different objects by distinguishing between them.)
Along with the new abilities provided by these instruments came a slew of questions like, “What is the difference between magnification and resolution” and “which is more important, to have raw enlarging power or the capacity to examine a particular sample in detail?”
Key Differences of Magnification and Resolution
Magnification is the process of enlarging objects only in appearance and not in physical size. In optical equipment, light is bent to magnify an image until the magnification can no longer be distinguished. While the definition of magnification is quite clear, it’s confused with the term resolution all too often.
The ability of imaging devices to show the full detail of the specimen being imaged is referred to as resolution. When viewed through the imaging instrument, the resolution also applies to the degree of clarity, fineness, and sharpness of the generated image.
The distance between two distinct and observable radiating points is the primary determinant of resolution. A single microscopic imaging system may consist of multiple individual parts, such as a lens, recording and display components, and so on. These parts contribute to the imaging apparatus’ optical resolution as much as the environment where the imaging is taking place.
The telescope and microscope are two of the oldest and most widely used optical instruments still in use today. Generally, telescopes are used to magnify images from a distance, while microscopes are used to magnify small objects, usually for research purposes.
Understanding the Limitations of Magnification and Resolution that Led to the Invention of Electron Microscopes
In the past, scientists were able to figure out why they were unable to see an unlimited amount of detail when peering through a microscope. As it turns out, objects with less than half the wavelength of the microscope’s illumination source will not be visible when looked at using that instrument.
In the case of light microscopes, they utilize visible light with a wavelength of 400 nm or a minimum of less than one-thousandth of a millimeter. This limit indicates that objects smaller than 200 nm or about the width of an average-sized bacterium won’t be visible to users while using light microscopes due to the quality of their lenses.
This, among other limitations of light microscopy, led scientists to develop electron microscopes were invented. EMs have a much higher resolving capability than light microscopes. Therefore, they can be counted on to deliver far more detail.
The movement of high-speed electrons has a specified wavelength, the way light does. Since the wavelength of electrons is a thousand times shorter than visible light, electron microscopes are designed to resolve objects that are also thousands of times smaller. Currently, electron microscopes can detect objects as small as 10⁻⁹ m, or one-twentieth of a nanometer. They are more than capable of seeing molecules, viruses, and even individual atoms at this range.
Theoretically, electron microscopes are capable of visualizing even smaller objects than they do now. Although they are currently equipped with limited resolution due to technical aspects of viewing samples, it’s highly likely that they’ll soon be able to view objects at the projected resolution limit of the most powerful electron microscopes.
Magnification and Resolution: Which is More Important?
Resolution and magnification are inextricably connected. High magnification is usually associated with high resolution. However, when a sample image is enlarged, its resolution experiences a dip. One of the main causes for this decline is the irregularity in the design of the imaging system’s lenses.
Often, when two objects held apart at a distance are magnified repeatedly, their edges become blurry, making it impossible to identify two separate objects.
End-users should keep in mind that high magnification without high resolution won’t allow them to distinguish between an object and its sub-cellular components, even if it makes the tiny sample visible.
In most cases, scientists depend on the resolution to identify the difference between a sample and its parts. However, the significance of magnification cannot be understated, as an end-user should first be able to magnify to the point where resolution becomes useful.
When purchasing an imaging system, researchers and scientists require both magnification and resolution. Although various users have different methods of achieving resolution, it’s preferable to have both. Having the best possible resolution and detailed magnification is optimal for capturing stunning images for scientific research and other purposes.