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Stereo Microscopes: Introduction
Microscopes are sophisticated instruments used to see and analyze small specimens. With impressive optical and mechanical features, microscopes provide three-dimensional enlarged images of small objects and structures. They are used across a variety of settings, such as medicine, forensics, education, and geology. Depending on the research goals, microscopists can choose between different types of microscopes – with stereo microscopes being essential tools in entomology, circuit board inspection, watch-making, and microsurgery.
Although different tools have different capabilities and applications, all microscopes are based on the concept of magnification. The interest in magnification can be traced back to the ancient world. Ancient Chinese scientists used water microscopes, while Greek philosophers utilized magnifying glasses in various settings; curved lenses were also utilized in ancient Egypt and Rome. Yet, the interest in lens technology peaked in the 13th century when lenses started being used for eyeglasses. The first compound microscope was created in the 16th century following the inventions of spectacle-makers Hans Jansen, Zacharias Jansen, and Hans Lippershey. Slowly but steadily, remarkable scientists such as Robert Hooke, Antonie van Leeuwenhoek, and Robert Brown launched and popularized microscopy across the globe.
Interestingly, the first pseudo-stereoscopic microscope (with reversed final images) was designed in 1677 by a French monk named Cherubin d’Orleans. Two centuries later, scientist Charles Wheatstone described the principles of stereoscopic vision, and inventor John Riddell developed the first practical binocular microscope, enhancing the development of the so-called common main objective stereo microscopes. Stereo microscopes have evolved significantly over the centuries. Today’s stereo microscopes are based on the Greenough principle, named after instrument designer Horatio Greenough who approached Carl Zeiss’ company in the 1890s with an alternative stereo microscope design with correct orientations of the final images.
How to Choose a Stereo Microscope?
Stereo microscopes are essential in microsurgery, entomology, engineering, and education. Due to the increasing numbers of models and competitors on the market, however, choosing a stereo microscope can be a challenging task. Some of the main factors to consider are:
- Research requirements
- Total cost
Research requirements: Depending on the research goals and the unit of analysis, researchers can choose between compound microscopes, stereo units, and digital models. For example, if users want to study solid objects or objects too big for a compound microscope, a stereo unit will be the most suitable option. Stereo microscopes, also known as stereoscopic or dissecting microscopes, are often used for dissection, fractography, manufacturing, forensics, and watch-making. As stated above, today’s microscopes are based on the Greenough principle to ensure the correct orientation of the final image.
Depending on the research requirements, the working distance is a major factor to consider. Note that some stereo microscopes can be modular units, which means that different bodies can be attached to different bases in order to manipulate working distances and match specific goals (e.g., boom stands for printed circuit board inspection). Interestingly, ergonomics and the number of users can affect purchasing; a rotatable head, for instance, can facilitate collaboration and facilitate group dynamics. Here we should note that while most microscopes share the same mechanical characteristics (e.g., base, head), stereo binoculars differ from compound binocular units. Unlike compound microscopes, stereo units use two optical paths (two objectives and two eyepieces) and provide different angles to the left and right eyes, which gives three-dimensional views of the specimen.
Specifications: Magnification and resolution are two of the main specifications to consider when choosing a stereo microscope. Stereo microscopes have two magnification systems: either a fixed (dual power) configuration or a zoom setup. Stereo microscopes are generally designed for analysis with low magnification (2X-100X). Note that a large working distance at low magnification allows the analysis of solid objects that can be manipulated easily (e.g., bugs, gems).
Additionally, illumination should be considered. While compound microscopes often use transmitted illumination (transmitted through an object from underneath), most stereoscopic microscopes use reflected light or incident light illumination (reflected off the surface of an object). This type of illumination is preferred for thick and opaque specimens. In some cases, however, transmitted illumination can be further employed during stereoscopic microscope use. Light sources can vary from halogen to LED systems, and fluorescent ring lights can be used as an additional light source. Note that stereo units with fluorescent ring lights are different than fluorescent microscopes.
Total cost: Microscopes can be broadly divided into two broad groups: high-power and low-power models. Although stereo microscopes have different powers, we should note that even a low-power microscope can be used for detailed examination (e.g., analysis of urine sediment).
Other factors that determine costs are optical quality, type of materials, and vendors. While high costs do not always mean high quality, notable vendors can offer top-notch products and adequate returns policies. Interestingly, Carl Zeiss is one of the oldest and most notable companies for quality products, founded in the middle of the 19th century. AmScope and OMAX are also popular manufacturers of high-quality products for both beginners and professionals. Note that OMAX products are often designed for professionals and semi-professionals and may require some levels of expertise. Other reputable brands include Celestron, Leica, and Nikon.
Best Stereo Microscopes
Stereo microscopes are invaluable tools in research and practice. Choosing a stereo microscope, however, can be challenging. Based on different configurations and reviews, here is a list of the best stereo microscopes available on the market:
Best Stereo Microscopes
Stereoscopic microscopes provide enlarged images of small objects and structures that are too small to be seen by the naked eye but too big to be manipulated via a compound microscope. Such units provide immediate engagement as they offer three-dimensional images. Children and young students are particularly interested in using stereo microscopes, which require minimal preparation and provide ease of manipulation. Dissecting microscopes can be used in a variety of settings, such as education, forensics, manufacturing, and research.
- Magnification: 10X-20X
- Head: Binocular
- Light: LED
AmScope SE400-Z Professional Binocular Stereo Microscope is one of the most sophisticated and popular stereo microscopes. The unit comes with a 1X objective lens and 20X and 10X widefield pieces. Additionally, the microscope is equipped with an adjustable gooseneck LED illumination system; it has a 17-inches boom arm and allows a working distance of 12 inches. AmScope SE400-Z is all-metal and stain-resistant, which makes it an invaluable tool in biology, metallurgy, chemistry, and engineering.
- Magnification: 10X-80X
- Head: Binocular
- Light: Halogen
AmScope SE306R-PZ Forward Binocular Stereo Microscope has high magnification capabilities (10X-80X) and comes with 2X and 4X objectives. The unit is equipped with widefield lenses and an upper and a lower halogen illumination system. AmScope SE306R-PZ Forward Binocular Stereo Microscope can be used in different settings, such as forestry, archaeology, education, and soldering.
Best Digital Stereo Microscopes
Digital microscopes are increasing in popularity as digital cameras allow images to be viewed, modified, and stored on an external device. Moreover, large displays can reduce eye fatigue. When choosing a digital microscope with a camera, microscopists should consider factors, such as connectivity, USB ports, and complimentary software.
- Magnification: 20X-80X
- Head: Binocular
- Light: LED
OMAX 20X-40X-80X Cordless Dual LED Lights Stereo Binocular Microscope with USB Digital Camera (OMAX CS-G223E) is a sophisticated cordless stereo binocular LED unit (with upper and lower LED illuminators). It can be powered by 110V power supplies or batteries, which makes the microscope usable in outdoor settings. The unit comes with a USB digital imaging system on one of the eyepieces, allowing images and live videos to be recorded. The included software is compatible with Windows XP/Vista/7/8/10 and Mac OS. With different advanced settings, OMAX 20X-40X-80X Cordless Binocular Microscope is suitable for analyzing coins, stamps, rocks, insects, and plants.
- Head: Trinocular
- Light: LED
OMAX 3.5X-90X USB3 18MP Digital Trinocular Zoom Stereo Microscope provides a great user experience. The unit is equipped with a rotatable trinocular head, a stable desk stand, and an 18MP USB 3.0 camera (4912×3684 pixels). Note that the software is compatible with Windows, Mac OS X, and Linux operating systems. Additionally, the model is equipped with a 144-LED ring light system. This stereo microscope can benefit watch-making, electronics, and biological research. In fact, OMAX 3.5X-90X USB3 Digital Trinocular Zoom Stereo Microscope is one of the most powerful stereo microscopes on the market.
- Head: Trinocular
- Light: LED
AmScope SM-4TZ-144 Professional Trinocular Stereo Zoom Microscope is one of the highest-rated stereo microscopes. The unit provides a high degree of freedom as users can utilize a 0.7X-4.5X zoom objective lens or manipulate the magnification levels ranging from 3.5X to 90X. It comes with a 360-degree rotation head, which can be positioned on three axes (X, Y, and Z). Additionally, this microscope is equipped with a double-arm boom stand (20-inches arms and 17-inches pillar), which facilitates manipulation. Note that the vertical trinocular port can be converted into a C-Mount or 23mm photo port (the camera is sold separately). With its complex configurations, AmScope SM-4TZ-144A Professional Trinocular Stereo Microscope is one of the most powerful dissecting tools in microscopy.
Maintaining Stereo Microscopes
Stereo microscopes are fundamental tools that can be used in various settings, such as medicine, education, engineering, manufacturing, and entomology. With the latest advancements in lens technology, users can choose between different types of stereo microscopes. Nevertheless, maintenance is vital to guarantee accurate and long-term exploitation:
- Handling the unit: As mentioned above, microscopes vary depending on their optical, mechanical, and digital configurations. Yet, one of the main rules to keep microscopes intact is to hold the unit by its base and support arm. The lenses require special care; microscopists and students should keep the lenses away from sharp objects or immersion oil.
- Cleaning the unit: Cleaning is essential. Lenses, in particular, require special care (e.g., lens papers or wipes for cleaning). Note that all pieces can be taken apart and cleaned after use.
- Storing the unit: Storing is another step to ensure long and accurate exploitation. Note that microscopes should be stored in dust covers.
- Maintaining the unit: Using a new unit requires practice and expertise. Therefore, users should consult both manuals for adjustments and instructions for use. Annual maintenance checks are also essential to guarantee accuracy and safety. Note that most units should be serviced professionally every 200 hours of use or every three years.
Stereo Microscopes: Conclusion
Stereo microscopes, also known as dissecting microscopes, are fundamental instruments in scientific research and practice. They provide enlarged images of small objects and structures, which are too small to be seen with the naked eye but too big to be analyzed through a compound microscope. The main difference between compound and stereoscopic microscopes roots in their different magnifications; while compound microscopes can reach up to 2500X, stereo microscopes have magnification up to 100X. This fact makes stereo microscopes highly valuable in the analysis and measurement of coins, tektites, minerals, fossils, jewelry, watches, circuit boards, and botanical specimens. Stereo microscopes are also used in dissection and microsurgery, as users can control for working distances. Digital stereo microscopes, in particular, are increasing in popularity as they facilitate data sharing and storage, and big screens relieve the eye strain that comes with extensive microscope use. Note that some units, such as AmScope SM-4TZ-144A Trinocular Stereo Microscope, can be attached to a digital camera sold separately.
Based on the concept of magnification, microscopes have undergone significant transformations over the centuries. While there are different types of microscopes and reputable vendors, choosing a stereo unit can be challenging. Researchers should balance study requirements, specifications, and budgets all at the same time. With complex features and advanced capabilities, microscopes are valuable scientific tools that can facilitate the accumulation and dissemination of knowledge, transforming the world of science.