Microscopes are so versatile and dynamic that trying to choose the best type can be daunting. As with any optics purchase, the most important step is determining how you want to use the microscope, your level of comfort and skill, and how much you’re willing to fork out to get the best bang for the buck. In this article we’ve focused primarily on desktop models. You can certainly buy a telescope that will fill an entire room, but chances are you’ll already know a thing or two about microscopes if that’s your market. Here we’ve broken down each type of desktop microscope and provided some suggestions on how to find the perfect fit for your needs.
In a compound microscope, light comes from the bottom and shines up through your specimen. You get a high rate of magnification, but your specimens need to be translucent enough to allow light to pass through them. They’ll also need to be roughly cell size, as the magnification power of a compound microscope will blur out anything too large, and your field of view will be too small to capture your specimen properly.
Compound microscopes come with different eyepiece arrangements. Monocular (for one eye), binocular (both eyes), and trinocular (both eyes and a camera). A single light path forms the images, which means they’ll appear in 2 dimensions through your eyepiece. The objective lenses are typically mounted on an adjustable nosepiece to change your fixed magnification strength.
To find the magnification strength of your microscope, multiply the objective lens strength by the eyepiece strength. For example, a 40x objective lens coupled with a 10x eyepiece would yield 400x magnification. Most compound microscopes range from 40x to 1600x magnification, though the use of oil immersion lenses can boost that up to 2000x. You can use special lenses to change your image quality, as well. A Barlow lens can multiply your total magnification strength. A condenser lens sends light through your sample and into the objective lens, but you can replace these with a darkfield lens (which creates a dark background for contrast with stained samples) or a phase contrast lens (increases contrast by quartering light wavelength). You can also use a disc diaphragm to adjust your light output.
In contrast to a compound microscope, a stereoscopic microscope provides light from the top and is meant for larger, more opaque specimens. These will reflect the light enough for a high-quality image. What makes the microscope stereoscopic, however, is the double light paths coming through your lens, which create a layered image that appears three dimensional. This is great for doing dissections, observing fossils, or even fine work like circuit board repair. The downside is, a stereoscopic microscope has much less magnification power than a compound microscope. If you’re looking at larger objects, though, the lower magnification helps to keep your image sharp.
Due to the layered light path, stereoscopic microscopes are built with binocular or trinocular eyepieces. Trinocular eyepieces are perfect for microphotography of fossils and gems and can add a new layer of excitement to your device.
You have the option of fixed position objective lenses or zoom power lenses with a stereoscopic microscope. Fixed position lenses make using your microscope much easier, which is perfect for beginners. Zoom power lenses give you more flexibility in magnification range, but they can be more challenging to use because of the fine focus adjustments. You can use a Barlow lens with this one, as well, to multiply your magnification strength. Most stereoscopic scopes range from 40x to 400x magnification, but if you’re using oil immersion lenses you can harness up to 2000x.
Despite their reputation as being large, room-filling devices, it is possible to buy a desktop-size scanning electron microscope (though be prepared to pay top dollar). They’re not poor performers, either. You can use a desktop SEM for up 90% of the most common SEM uses. You’ll get images more quickly and spend less time on sample preparations (though you’ll be unable to use living specimens). CryoSEM involves the use of frozen samples, which is perfect for botanical specimens, and TEM microscopes can be used for viewing thin cross sections for viewing internal structures at high resolution. Electron microscopes more than beat the competition in power, too. You can harness an impressive 500,000x magnification with one of these.
The world of microphotography will take your microscope usage to a new level. Physicians and laboratories can even use this technique to share images and research. While it’s possible to hold a digital camera up to the eyepiece to snap a photo, using a trinocular device with a camera mount will give you much higher quality images. Some microscopes even come equipped with affordable built-in computer imaging that you can connect right to your computer via USB.
There are endless ways to use a microscope, but we’ve outlined some of the more common uses of compound and stereoscopic microscopes to help you find the best fit for your money.
Studying the microstructure of food items can be eye-opening. While the smallest structures are best viewed with an electron microscope, microorganisms can be detected using stained samples in a compound microscope. If you need to see more details of the food such as foreign contaminants, a stereoscopic microscope if best.
This also depends on what kind of detail you need from your specimen. Insects and plant matter are perfect beneath a stereoscopic microscope, but the more detailed cellular life of biological specimens is best suited for a compound microscope. An electron microscope can’t be used for any living matter, so you may need to avoid these when studying biology unless you’re looking at dead and disposable specimens.
Without question, you’ll need a compound microscope for blood and bacteria, along with a darkfield lens or phase contrast lens for high contrast visibility.
Seeing the finer details on a circuit board is crucial for repair. But because of their size and opacity, you’ll need to avoid compound microscopes for this task. Go for a stereoscopic microscope with a zoom power lens to ensure you can get the perfect image.
A stereoscopic microscope is best for coins, as well. A coin’s high reflectivity is perfect for the top-down lighting, and the lower magnification (shoot for 10x to 30x) is ideal for seeing scratches and other imperfections on the coin’s surface.
You’ll definitely want light from the top in a dissection, as well, so you can see the details of your work. The lighting dynamics and three-dimensional effects of a stereoscopic microscope are perfect for this. This is also a great opportunity for microphotography, so look for a trinocular scope as well.
An SEM is ideal for studying gunshot residue and other trace evidence, but for ballistic analysis you’ll want a stereoscopic zoom microscope. For identifying drug structures, a compound microscope is your best bet.
Finding a jewelry/gem microscope is simple, as most are marketed as such. Most will be stereoscopic and come with a trinocular eyepiece for microphotography. You can achieve some amazing images with this kind of setup, and the price point is reasonable.
To keep things simple, we’ve provided a cost range for middle-of-the-road devices of each microscope type. Compound microscopes come with a multitude of options, but a decent model will fall in the $200 to $600 range. Stereoscopic microscopes run around $150 on the low end, but when you add digital photography capabilities you can go anywhere from $300 to $1000. Electron microscopes can be cost-prohibitive at any size and can be difficult to get your hands on. If you’re a beginner or don’t have the budget to buy a microscope for the price of a car, stick with a humbler compound or stereoscopic version.
Do look carefully at your microscope model before you purchase. Make sure it has the features you need to perform the necessary tasks and be sure to take magnification into consideration as well. You may find a great price tag on a compound microscope, but if you don’t need to look at cellular-level detail, you should probably start shopping for a stereoscopic, instead. Once you make that final decision, be sure to keep your microscope properly clean, store it with a cover over the top, and keep it away from light sources and vibration. If you take care of your investment, it’ll last you a lifetime.
Did you also know that pocket microscopes are now a thing? We were surprised and put them to the test in this article.
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