Occasionally parents of my students contact me (usually around Christmas time) for advice because they want to buy a microscope as a present for their children. In the best case, they ask which microscopes we use in biology lab in school, in some other cases, they show me an advertisement for toy microscopes (often advertised with a 1000x magnification) and then ask me if the magnification is high enough to see cells. Only insiders know that anything beyond 400x magnification is probably not useful for beginning observation anyway. It is for this reason, that I decided to compile a short FAQ to help parents a little in finding an appropriate microscope. The last time when I was asked for advice, I showed the parent a microscope that we used in school and gave a quick introduction into stereo and compound microscopes. I then also showed the parent a catalog with school supplies, and gave the advice to contact them.
How much can I expect to pay for a microscope for children? The minimum price for a useable microscope is around EUR 150/USD 200 and up. You would probably like to spend a bit more, but cheaper devices also exist which provide a useful picture, but may be less convenient and stable to use. EUR 300/USD 400 should give you already a very decent device. This is the price that many educational microscopes in schools have. Anything much less than EUR 150/USD 200 is likely not to be of sufficient quality, but simply because a microscope is expensive does not mean that it is automatically suitable. Specialized optics may quickly drive the price up, but may not be suitable or required. If you are buying blindly then you may spend money on unnecessary things, or waste money on a quite useless device. As a matter of fact, some individual microscope objectives can be more expensive than the whole microscope (microscopes are modular).
How are cheaper microscopes different from more expensive ones? Modularity of the microscope, use of more specialized objectives and optics (plan objectives, apochromatic objectives… not needed for children) and quality of machining as well as brand name drive the price up. Devices containing many metal parts are more stable but also more expensive to manufacture.
What can I expect to see under the microscope? This depends to a large extent on three factors: The type of microscope (stereo or compound), the quality (resolution) of the optics and (of course) the specimens that you look at. The type of microscope determines to a certain extent also the specimens that you can look at. With stereo microscopes you can observe opaque objects, such as rocks, whole plant parts or insects. With compound microscopes you can observe the much smaller cells.
Which type of microscope, stereo or compound, should I buy? The choice of the right microscope type (stereo vs compound) is a fundamental issue. After all, you do want to keep the child interested. Buy stereo microscopes if the child is very young (up to 10 years) or if you want to do uncomplicated natural observation without much specimen preparation. Buy stereo microscopes also if you want to extend an already existing hobby or interest such as stamp collecting, collecting coins, minerals, rocks, insects and butterflies or plants. These objects can all be directly viewed under the stereo microscope, without destroying them. Buy compound microscopes if you or your child is also interested in specimen preparation or if you are interested in seeing smaller objects. Older children may be more interested in compound microscopes, as this is the kind that gives more “interactivity” and more possibilities for preparing specimens. Older children may also be interested in making a slide collection. The children can use different magnifications and have to learn to operate both the coarse and fine focus knobs. If you want to to observe water samples and cells, then compound microscopes are the way to go. Be aware that some children may not consider stereo microscopes as “real” microscopes and that they may be disappointed if they are not able to observe paramecia and other small water life that they read about in books. Also be aware that compound microscopes need more guidance and practice, especially if specimens are to be prepared. Many of the following FAQ will deal with compound microscopes. For more information about these two types of microscopes, read: Types of Light Microscopes.
Where can I buy microscopes? Microscopes can be bought from specialized microscope dealers. These often also supply schools and universities with microscopes. Do not buy second hand devices unless you really know what you are doing. There are simply too many things that can go wrong, even if the quality of the second hand microscope is otherwise quite good. It’s well possible that second hand microscopes are equipped with specialized objectives that are not suitable (or simply too expensive) for children. Unlike consumer products, which come out of the box, microscopes are commonly assembled according to the research needs and second hand microscopes may have a research or medical background. It is probably best to personally get advice from a microscope shop.
Is there one single criterion that I should look out for when buying a compound microscope? Look for two things in microscopes. The microscope should be made of metal (and be heavy) and the objectives should be DIN standard. Look at the objective of the microscope and check if it has the number 160 written on it. This refers to a 160 mm tube length. Microscopes that are able to accept these optics often (not always) have a minimum quality. Most educational and routine microscopes use these, plastic toy microscopes do not. These objectives are interchangeable with each other. Microscopes that use infinity corrected objectives have an infinity sign printed on them and are expensive and can be found more on research microscopes. I just mention this for the sake of completion. The material of which the body of the microscope is made is also relevant. Devices made mostly of plastic can be considered toys, and these do not provide the stability and optical quality to keep children interested over a longer time period.
Do my children need support? A microscope is a scientific instrument and it use requires appropriate education and support. After all, inappropriate handling may damage the device (crashing the objective into the slide, for example). Sooner or later the child will have observed all the provided slides and samples and will want to observe new things. Guidance is then needed to prepare more samples (unless you buy ready-made slides). Safety issues must also be considered: How can you protect the microscope and how can you protect the child? Some chemicals used for preparing samples are toxic, do not use them and do not blindly trust them. There are also many non-toxic alternatives around, however, and the parent may need to do a bit of research. There is also the danger of cutting oneself, when preparing samples. You may also need to do some research on the different types of specimens that can be observed – yes a microscope does require some guidance.
Should I buy a second hand microscope? Unless you have worked with microscopes yourself and unless you know what you are doing, I would not buy them second hand. Maybe you know a trustworthy second hand dealer, in this case I would also take second hand microscopes into consideration. Be aware that a quality second hand microscope (such as the “Zeiss Standard”) can be obtained for a fairly low price, but that this microscope provides much greater value than new no-name devices, which may be more expensive. Without advice you run the risk of buying a microscope with objectives that are not appropriate for education, or microscopes that are not operating reliably. There is no way to see from a picture if the objectives are intact, if there is no stage drift and if the gear operate smoothly. Hospitals and research institutions sometimes sell useful used microscopes, but these may be equipped with specialized optics. Also do not buy microscopes from people who do not know much about them. Non experts are not able to assess the quality of a microscope. There are so many things that you have to look out for, that it is not possible for me to summarize this in a few lines. I may write a second FAQ about them.
Is there anything that I should not buy? Do not buy second hand microscopes unless you also buy them from a shop, which is able to give warranty and service. Do not buy specialized microscopes such as inverted microscopes, metallurgical or polarizing microscopes. Again, if you search Ebay, you may not always know the difference. Do not buy scopes that have only a mirror instead of a lamp. Kids may point them to the sun and destroy their eye sight. Mirrors also do not provide enough light intensity. Do not buy historical microscopes. They should go into the museum and also may not have the optical quality (fungal growth on the optical surfaces is a problem, etc.).
What’s the problem with plastic (“toy”) microscopes? These are microscopes that are sold in a colorful cardboard and Styrofoam box together with a wide range of different accessories. There is a general agreement among enthusiast microscopists and teachers that these microscopes should not be bought. First, they are not as cheap as one may think and for a little more money one can already obtain a microscope with substantially better optics. Toy microscopes are often difficult to focus often lacking a coarse and fine-focus knob. Do not forget, that the tolerances of the mechanics has to be extremely narrow. Plastic gears simply can’t keep up with metal gears. They do not have standardized objectives and the resolution of the picture is low. Often the magnification is also advertised as unrealistically high (1000x). The low light intensity (battery operated or mirror) makes it difficult to see the specimens properly. If money is indeed an issue, then it’s better to get a simple but solid stereo microscope. They are more fun to use. In my opinion, children need stable and solid devices that produce a sharp, contrasty and bright image. Kids are demanding these days. The images that the microscope produces has to compete with the strong visual impressions from television, the Internet and magazines. A low-contrast, washed-out, dark picture produced by a toy microscope will not captivate the children for an extended time. My 2 cents. Download Microbehunter Magazine (November 2011) for a comparison between toy microscopes and more suitable microscopes.
I already bought a toy microscope! What should I do? Keep it and buy a “real” one and compare the image quality. Then write an article about it for this magazine.
Where can I save money? You do not need: Köhler illumination (for photography through the microscope), 100x oil immersion objective (more expensive and difficult to use for children). Actually I really dis-advise getting a 100x oil immersion objective. This requires the use of immersion oil, which is messy to use and has more specific applications. You also do not need phase contrast and DIC, these are expensive anyway. Plan objectives are more expensive and useful for photography. I mention this, because second-hand devices may come with these. A bright-field condenser with a filter holder beneath the stage is highly recommended, however. This allows for simple dark-field microscopy (bright specimen on dark background), if you insert a dark-field patch-stop into the filter holder. A device with a mechanical stage (and not only stage clips) is very recommended. It makes operating the microscope easier. A mechanical stage allows you to move the specimen slide horizontally and vertically by turning two knobs.
Which objectives and eyepieces should I buy? Buy achromatic DIN objectives with the magnifications 4x, 10x, 40x and a 10x eyepiece. A 100x oil immersion is not needed and may even be counter-productive. This objective requires advanced techniques and is more expensive. Better to get a 60x objective instead (more rare), but this is optional. This is a standard combination and microscope dealers supplying for schools will already offer these combinations.
Should I buy a microscope with a “name” or a no-name device? This is a long question to answer and the opinions diverge on this issue. From a quality perspective, all “big four” microscope manufacturers (Olympus, Nikon, Leica, Zeiss) produce quality microscopes and also have cheaper introductory microscopes for schools in their program. Still the cost of these microscopes is often higher, but also their resale value. Many no-name devices do carry the name of the importer, and the quality can cover a wide range. I personally have a rather pragmatic view on the issue. If one wants is not able or willing to spend much money on a microscope, then a “no-name” device is probably the only way to go (unless one buys second hand). Some people think that it is better to buy a used “big four” microscope than a new “no-name” microscope of the same price, also because of the higher resale value. I would dare to say that for beginners it may be very difficult to judge the quality of a used device. Of course one can also buy used (and well serviced) microscopes from a dealer, and this is indeed a possibility.
During my beginning days of microscopy, I once talked to a “big four” microscope manufacturer. I was quite surprised that he gave me a surprisingly balanced advice on which microscope combination to buy. He could easily have sold me a microscope which would have been much more expensive (and also not suitable for my needs). I was a beginner. The salesman was quite honest and told me that they have no interest in selling me a microscope which is too expensive and not suitable, for the sake of earning quick money. I summarize his words: “We have a long-term view. The beginning microscopy users of today are the researchers of tomorrow. We want to keep beginners and children interested in microscopy. If the microscopy enthusiasts have a good view about our company (and do not feel ripped-off), then they will also purchase our microscopes when they are in a position to decide if they should equip a whole laboratory with microscopes.” Interesting point.
What about “computer microscopes” Back in 1999, Intel introduced the QX3 Play microscope, which needed to be connected to a computer. The QX3 was later replaced by the QX5. You can read an extensive QX5 USB microscope review here. The image quality of this device seems to be good, and I already have read several positive reviews about this device. It has the advantage that this microscope is able to cover both worlds, the world of compound and of stereo microscopes. Still, these microscopes are sold as “toys” and (according to a review I read) are not able to provide the same image quality as dedicated student and educational microscopes (of comparable price). A disadvantage is, that it is necessary to connect the device to a computer in order to see something (it has no eyepiece). Microscopes like these are not standard and if you want to teach children proper microscopy use (operating the fine and coarse focus, operating the diaphragm, changing objectives, proper microscope cleaning, etc.) then I would get a standard device. You can also take pictures through a regular microscope with a compact camera using afocal photography.
What accessories are needed You also need: an introductory book about microscopy (to keep the children motivated), slides and cover glasses, and tweezers. These things are not expensive. I also highly recommend that you get a slide box with ready-made samples from a wide range. Do not get slides made for medical students, which show a wide range of different anatomical sections (boring). Get slide boxes that contain both plants, insects, animal tissue, water samples, sand, radiolaria, etc, etc. To keep the children interested. This way the children have something to look at right away, without the need to prepare slides on the day they receive the microscope.
This all may sound complicated. What is the easiest approach? Find a dedicated shop selling microscopes and contact them. Often educational supplies companies will have several microscopes in their product range. Other companies are specifically specialized for microscopes. Study the catalog, do some research (your kids will need support preparing the samples anyway). Write them an email and be honest about the needs. Tell them that you need a scope for your kids and also tell them if it should be a compound or stereo microscope. A serious dealer will know the requirements and will not sell you an inappropriate device. They are interested in long term customer relationships and not in quick money.
Comments and opinions are appreciated!