Stereo microscopes are low-power microscopes designed for observing insects, plants, rocks, jewels, stamps and coins, etc., also used for inspections. It is also possible being used to observe slides. The total magnifications are 10x, 20x, 30x, 40x. In some cases you may need 60x-90x. You need to consider about the following aspects when you select a stereo microscope.
1. Magnification:
The total magnification can be calculated by the multiplication of the eyepiece power and the objective power. For example, if you have a pair of eyepieces of WF10X, and the objective is 2x and 4x selectable, the total power is 20x or 40x. Usually 20x-40x is enough for regular use but it's not bad to have extra eyepieces with higher power (e.g. WF20X) if budget is not an issue.
The total magnification can be calculated by the multiplication of the eyepiece power and the objective power. For example, if you have a pair of eyepieces of WF10X, and the objective is 2x and 4x selectable, the total power is 20x or 40x. Usually 20x-40x is enough for regular use but it's not bad to have extra eyepieces with higher power (e.g. WF20X) if budget is not an issue.
2. Zoom or fixed power:
Zoom microscopes have zoom objectives, just like your zoom cameras. The magnification is gradually changed by turning the zooming knob. The common zoom ratios are 1:4 and 1:6.5, or higher. The higher ratio, the better, but the more expensive. The popular objectives are zoom 1x-4x and zoom 0.7x-4.5x.
Zoom microscopes have zoom objectives, just like your zoom cameras. The magnification is gradually changed by turning the zooming knob. The common zoom ratios are 1:4 and 1:6.5, or higher. The higher ratio, the better, but the more expensive. The popular objectives are zoom 1x-4x and zoom 0.7x-4.5x.
Fixed power stereo microscopes are inexpensive. They have fixed power objectives. Usually they have one or two rotatable objectives, e.g., 2x, or 4x, or 1x/3x, 2x/4x. The cost for having zoom or fixed power is significant.
3. Number of eyepieces (monocular, binocular and trinocular):
Monocular microscopes only have one eyepiece. That means you may only use one eye to observe the specimen. If you have an electronic eyepiece (USB Digital camera), you will have no way to view it with your bare eye at the same time. The pros for monocular are inexpensive and light weight. Binocular is the most common selection. It's comfortable for your eyes if you get used to it (it may take some time for beginners to get used to it). Trinocular has a third eyepiece tube for electronic eyepiece. For some models, you may have to pull or push a lever to switch the views. Of course, trinocular is the most expensive out of the three forms.
Monocular microscopes only have one eyepiece. That means you may only use one eye to observe the specimen. If you have an electronic eyepiece (USB Digital camera), you will have no way to view it with your bare eye at the same time. The pros for monocular are inexpensive and light weight. Binocular is the most common selection. It's comfortable for your eyes if you get used to it (it may take some time for beginners to get used to it). Trinocular has a third eyepiece tube for electronic eyepiece. For some models, you may have to pull or push a lever to switch the views. Of course, trinocular is the most expensive out of the three forms.
4. Working Distance:
Working distance is the distance between the bottom of the objective and the top of the specimen when it is focused. The larger working distance, the better. Large working distance allow you to have more options for illumination (like ring light, gooseneck cold light) and spare room for operation. The working distance could be significantly changed by adding auxiliary objectives. Usually a 0.5X auxiliary objective could get double working distance.
Working distance is the distance between the bottom of the objective and the top of the specimen when it is focused. The larger working distance, the better. Large working distance allow you to have more options for illumination (like ring light, gooseneck cold light) and spare room for operation. The working distance could be significantly changed by adding auxiliary objectives. Usually a 0.5X auxiliary objective could get double working distance.
5. Illumination:
Illumination is important for microscopes. Two lights (upper and lower) are better than one. Being able to adjust brightness is better than not being able to. For boom stand microscopes, ring lights or gooseneck cold lights are the best options. Tungsten lights are cheap but have large size and short lifetime. Halogen lights are compact, bright and have long lifetime. Fluorescent lights are brighter than halogen and the color temperature is cold (5000K-7800K). LED ring lights have the longest lifetime and produce very little heat, better for long time operation.
Illumination is important for microscopes. Two lights (upper and lower) are better than one. Being able to adjust brightness is better than not being able to. For boom stand microscopes, ring lights or gooseneck cold lights are the best options. Tungsten lights are cheap but have large size and short lifetime. Halogen lights are compact, bright and have long lifetime. Fluorescent lights are brighter than halogen and the color temperature is cold (5000K-7800K). LED ring lights have the longest lifetime and produce very little heat, better for long time operation.
6. Quality of lenses and mechanism:
The quality of lenses and mechanism has direct impact on the sharpness and accuracy of the image. The appearance of the product will show the quality of the products. You may have a basic idea from the photos.
The quality of lenses and mechanism has direct impact on the sharpness and accuracy of the image. The appearance of the product will show the quality of the products. You may have a basic idea from the photos.
7. Accessories you may need
a. Microscope Digital USB Camera (electronic eyepiece): for watching through computer monitor or TV and taking pictures of the objects.
b. Darkfield: for observing three-dimensional objects-- diamonds and gemstones. It creates beam lights to watch the details not available through other forms of lights.
c. Jewel tweezer: for jewel or other object inspection. 3-way movement and rotation make it easier to watch from different angles.
d. Boom stand: for viewing objects with large area.
e. Extra light source: ring light or gooseneck cold light could be a backup light source.
f. Extra eyepieces: get wider range of magnification.
g. Auxiliary objective: usually a 0.5x auxiliary objective gives you large view field and double working distance.
h. Spare bulbs, ring light tubes with different color temperatures.
a. Microscope Digital USB Camera (electronic eyepiece): for watching through computer monitor or TV and taking pictures of the objects.
b. Darkfield: for observing three-dimensional objects-- diamonds and gemstones. It creates beam lights to watch the details not available through other forms of lights.
c. Jewel tweezer: for jewel or other object inspection. 3-way movement and rotation make it easier to watch from different angles.
d. Boom stand: for viewing objects with large area.
e. Extra light source: ring light or gooseneck cold light could be a backup light source.
f. Extra eyepieces: get wider range of magnification.
g. Auxiliary objective: usually a 0.5x auxiliary objective gives you large view field and double working distance.
h. Spare bulbs, ring light tubes with different color temperatures.
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