Buying a microscope may seem straightforward, but it can quickly become overwhelming due to the variety of options available. With each model designed for specific purposes, choosing the right one can be tricky. Every microscope offers unique features and capabilities, helping you explore new discoveries and excel in your field.
Types of Microscopes
Compound
Among the many types of microscopes, the compound one is the most popular. It’s also known as a biological microscope. A stable, technologically advanced compound microscope has high magnification. It uses a compound lens system, meaning, it has multiple lenses. More lenses means more magnification.
These types of microscopes have several subcategories. The first one is a phase contrast microscope. This one uses a phase contrast objective lens and either a phase slider or a phase condenser to add contrast to the sample without staining it. They’re mainly used to observe blood cells or bacteria.
The second one is the polarizing microscope. This one is used as a polarizer and an analyzer for cross-polarizing the light and recognizing the colour differences of the thing that’s being analyzed. This is a microscope used in the pharmaceutical industry for examining chemicals. Geologists and petrologists use it as well to study thin slices of rocks and minerals.
A metallurgical microscope can only see reflections or both transmitted and reflected light. The objective lens lets this reflected light come through. It’s mainly used in industrial settings when there’s a need for large magnification of the samples (especially metals). Some models even use darkfield microscopy. This is a technique that will emphasize specific features of the sample such as fractures and flaws.
Last but not least is the fluorescence microscope. It’s also known as DIC or differential interference contrast) microscope. It works by using various light wavelengths to fluoresce a sample and allow you to study and examine it more precisely.
All of these microscopes provide a two-dimensional image. Their magnification range is around 40x-1000x and have an all-metal construction. This makes them strong, stable and very durable. They’re great to use in a lot of surroundings such as schools, labs, on-field use and much more.
Stereo
With stereo microscopes, you can examine a wide range of samples that are pliable enough to hold them in your hands. A stereo microscope usually has a magnification of 10x to 40x and produces a 3D image, or a “stereo” image. This is a very versatile microscope that can be used in many different surroundings such as science, coin collection, botany, manufacturing, quality control and more.
A stereo microscope can give you reflected and transmitted illumination. Plus, you can use it to examine a simple that doesn’t let light pass through. The most common samples observed using this microscope are coins, plants, insects, metal or plastic parts, fabric weaves, wires, printed circuit boards and even for observing frog anatomy.
Inverted
There are two types of inverted microscopes: metallurgical and biological. The magnification in the biological once is 40x, 100x, and occasionally 200x and 400x. This makes looking at living samples in a petri dish possible. You place the dish on a flat surface and the lenses are housed beneath the stage.
The inverted microscopes are mainly used for cell biology, live cell imaging, in-vitro fertilization, developmental biology, microbiology and neuroscience. People use them to analyze and research tissues and cells. Metallurgical microscopes are very unique. They’re used to find fractures and faults in larger samples with extreme magnification.
They’re very similar to the biological inverted microscopes. The only difference is that there’s no petri dish. Instead, scientists find or make a smooth side of the sample so it can sit flat on the surface. This polished, smooth sample is also known as a puck. Just like the compound microscope, this one is very practical and widely used.
Metallurgical
Metallurgical microscopes are made for observing samples of objects that don’t let light go through them. They have a magnification of 50x, 100x, 200x, and sometimes 500x. They can observe and examine micron-level cracks in metals, paint and grain sizing. They’re most commonly used in automobile manufacturing and by companies that work with and analyze metal structures, glass, composites, ceramics, wood, liquid crystals and polymers.
Polarizing
Polarizing microscopes use polarized light combined with reflected illumination or transmitted illumination. They’re used to examine minerals, rocks and chemicals. They’re used daily by pharmaceutical companies, geologists, chemists and petrologists. These microscopes have an analyzer and a polarizer. The analyzer determines how much light passes and in which direction and the polarizer allows just certain light waves to pass.
How to Choose a Microscope
Magnification
It doesn’t matter if you have to buy compound microscopes or metallurgical ones, the magnification options are the same. Microscopes have 2 magnification sources, the eyepiece and the objective lens. You get the overall magnification by multiplying the lens power by the eyepiece. For example, if the eyepiece is 10x and the lens is 2 you get a total magnification of 20x. Some microscopes can have up to 5 objective lenses and they’re usually found in labs and clinics.
Microscope Head
Microscopes can have 3 different heads, monocular, binocular and trinocular. The monocular ones are often used in schools, binocular are good for any adult and the trinoculars have a camera in the third piece which is intended to take pictures and videos of the sample as you’re working on it.
Coarse or Fine Focus?
Have you noticed the small knob on the side of the microscope? That’s the focus knob. If it’s just the knob it means it has a coarse focus. If it has another smaller knob on top of it, it means it has fine focus as well. It’s always a better idea to have both because that way you’ll get a clearer picture of the sample and focus on smaller particles.
Light Source
Things like heat, lamp, colour accuracy and ease of replacement will help you decide which type of light to get on your microscope. Incandescent lights are warm and inexpensive but will heat up quickly and have a short life. Halogen lights are bright, warm, and easy to replace but don’t come with a dimmer and have a short life.
Fluorescent lights have a white light with no heat and have a low lamp life. LED lights are very bright and don’t have any heat. They often come with a dimmer and have a long lamp life. They’re also cheap and aren’t difficult to replace. However, some researchers find them hard to work with because of the slight blue tint.
