Science
Make: Science Room – Choosing a microscope

MAKE_science_main_ALT2_190px.gifWe’re in the process of working on a new area of Make: Online that we’re really excited about. It’s called the Make: Science Room. We’ll have a full announcement and launch in a few weeks. In the meantime, we thought we’d give you a teaser of the type of content we’ll be offering. The following article, by Bob Thompson, author of Illustrated Guide to Home Chemistry Experiments, should help you in deciding which type of microscope is best for you. If you didn’t want/think you needed a microscope before, you will after you see all of what we have in store in the Make: Science Room and the Maker Shed! Stay tuned…


Choosing a Microscope by Robert Bruce Thompson

Ask any scientist to name the single most important tool for scientific study. Chances are, the answer will be a microscope. Without a microscope, we are limited to what we can see with the naked eye. Using a microscope reveals entire worlds that would otherwise be invisible to us. Obviously, a microscope is essential for the serious study of biology and forensics. Less obviously, a microscope is also an important tool in disciplines as diverse as chemistry, Earth science, and physics.

Every home scientist should make it a high priority to acquire a good microscope. The question is, which one? This article explains what you need to know to choose a microscope appropriate for your needs and budget.Price

First, let’s talk about price. Microscopes are available in an incredible range of prices, from $25 toy microscopes to professional models from German and Japanese manufacturers that can cost as much as a new Mercedes-Benz automobile. Literally. Toy models are obviously unsuitable for serious use, but few of our readers will have the inclination (or budget) to spend thousands on a professional model. Fortunately, there’s a happy middle ground of inexpensive, high-quality microscopes that sell in the $150 to $1,200 range. We’ll focus on that category.

All of these microscopes are Chinese-made. The best of the Chinese microscopes are very good, both optically and mechanically. Unfortunately, Chinese factories also produce boatloads of garbage microscopes, and it’s impossible to tell the difference just by looking at the scopes or comparing prices. The best way to get a good one is to buy from a reputable dealer. (And guess who now sells microscopes? Our very own Maker Shed.)

Microscope Types

Broadly speaking, two types of microscopes are useful in home science labs. A compound microscope, shown in Figure 1, is what most people think of as a microscope. You use it to view small specimens by transmitted light at three or four medium to high magnifications, typically 40X, 100X, 400X, and sometimes 1000X. A good compound microscope is essential for serious study of biology or forensics, and useful for many other sciences.

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Figure 1. A typical compound microscope (image courtesy National Optical & Scientific Instruments, Inc.)

A stereo microscope, shown in Figure 2, uses two eyepieces, each with its own objective lens, to provide a 3D image of the specimen. A stereo microscope (also called a dissecting microscope or an inspection microscope) operates at low magnifications, usually in the 10X to 50X range. Some models have fixed magnification, usually 10X, 15X, or 20X. Other models offer a choice of two magnifications, often 10X or 15X and 30X or 40X. Zoom models offer continuously variable magnification.

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Figure 2. A typical stereo microscope (image courtesy National Optical & Scientific Instruments, Inc.)

A stereo microscope is useful for examining relatively large solid objects at low magnification by reflected rather than transmitted light. Most stereo microscopes provide a top illuminator that directs light downward onto the specimen. Better models often also offer a bottom illuminator that allows specimens to be viewed by transmitted light.

For a home lab, a stereo microscope is useful but not essential. Buy one if you can afford it, but don’t skimp on the compound microscope. It’s better to buy a good compound microscope and no stereo microscope than to buy cheap models of each. If you don’t have a stereo microscope, you can substitute a magnifier or pocket microscope, or in some cases simply use your compound microscope at its lowest magnification.

Head Style

Compound microscopes may be available in any or all of the four head styles shown in Figure 3.

  • A monocular head provides only one eyepiece. This is the least expensive of the four head styles, and is suitable for general use.
  • A dual head provides two eyepieces, one vertical and one angled. The second eyepiece allows two people to view a specimen simultaneously, for example a teacher and a student. A dual head is also very convenient if you want to mount a still or video camera to image specimens. Dual head models typically cost $50 to $100 more than comparable monocular models.
  • A binocular head provides two eyepieces to allow viewing specimens with both eyes. One eyepiece is individually focusable to allow the instrument to be set up for one person’s vision. The advantage of a binocular head is that it’s less tiring to use over long periods and may allow seeing more detail in specimens. The disadvantage is that the focusable eyepiece must be adjusted each time a different person wants to use the scope. Binocular models typically cost $150 to $250 more than comparable monocular models.
  • A trinocular head provides two eyepieces for binocular viewing and a separate single eyepiece for viewing by a second person or for mounting a camera. Trinocular models typically cost $300 to $400 more than comparable monocular models.

At any particular price point, a monocular-head model offers the maximum bang for the buck. You’ll get better optical and mechanical quality with the monocular head than with any of the multiple-head models.

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Figure 3. Monocular, dual-head, binocular, and trinocular head styles (images courtesy National Optical & Scientific Instruments, Inc.)

Regardless of head style, most better models allow the head to be rotated through 360° to whatever viewing position you prefer. The left image in Figure 3 shows the traditional viewing position, with the support arm between the user and the stage. The other three images show the reversed viewing position, with the stage between the user and the support arm. Most people prefer the latter position, which makes it easier to manipulate slides, change objectives, and so on.

Illumination Type and Power Source

Early microscopes and some inexpensive current models have no built-in illuminator. Instead, they use a mirror to direct daylight or artificial light up through the stage and into the objective lens. Because any mirror small enough to fit under the microscope stage gathers insufficient light to provide bright images at high magnifications, such scopes are limited to use at low and medium magnifications unless they are equipped with an accessory illuminator. Most microscopes include built-in illuminators of one of the following types, roughly in order of increasing desirability:

  • Tungsten – the least expensive method, and the most common on low-end scopes, tungsten illuminators use standard incandescent light bulbs. They are relatively bright, but they produce a yellowish light and considerable heat. In particular as the light is dimmed, it shifts further toward orange. This warm color balance can obscure the true colors of specimens. The heat produced by the incandescent bulb may kill live specimens and quickly dries out temporary wet mounts made with water. Lamp life is relatively short.
  • Fluorescent – costs a bit more than tungsten, and was quite popular before the advent of LED illuminators. Fluorescent illuminators provide bright light that appears white to the human eye, but is actually made up of several different discrete colors that are mixed to appear white. Accordingly, color rendition can differ significantly from the true color rendition provided by daylight. Fluorescent bulbs emit much less heat than incandescent bulbs, and so are well suited to observing live specimens. Some fluorescent illuminators are battery-powered, but most use AC power. Lamp life is relatively long.
  • LED – priced about the same as fluorescent illuminators, LED illuminators have become very popular, largely replacing fluorescent illuminators. LED illuminators have the same color-rendition problems as fluorescent illuminators, but are otherwise ideal for many purposes. LED illuminators draw very little power and emit essentially no heat. Their low power draw means they’re the best choice for a battery-powered microscope, and are ideally suited for portable microscopes that can be used in the field. Lamp life is essentially unlimited.
  • Quartz-halogen – the most expensive type of illuminator, and the one preferred by most microscopists. They provide a brilliant white light needed for work at high magnification that reveals the true colors of specimens. Unfortunately, quartz-halogen lamps also produce more heat than any other type of illuminator. Their high power draw means they are AC-only. Lamp life is relatively short.

Choose quartz-halogen if it is available for the scope model you purchase. Otherwise, choose LED. Tungsten is appropriate only for an entry-level scope.

Nosepiece, Objectives, and Ocular (Eyepiece)

The nosepiece, also called the turret, is a rotating assembly that holds 3, 4, or (rarely) 5 objective lenses. By rotating the nosepiece, you can bring any a different objective lens (usually just called an objective) into position and change the magnification you use to view the specimen. Inexpensive microscopes use friction-bearing nosepieces; better models use ball-bearing nosepieces with positive click-stop detents. Figure 4 shows a typical nosepiece with three objectives visible.

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Figure 4. A typical microscope nosepiece with objective lenses

The nosepiece may be mounted in the forward position (tilted away from the support arm) or reverse position. If you use the scope in the forward viewing position (with the support arm between you and the stage), having the nosepiece mounted in the forward position makes it a bit easier to change objectives. If you use the reverse viewing position, it’s easier to use a nosepiece mounted in the reverse position.

Objective lenses are usually color-coded to make it obvious which one is currently being used. The standard color codes are red (4X), yellow (10X), green (20X), light blue (40X or 60X), and white (100X). Not all manufacturers follow this standard.

Inexpensive microscopes usually provide three objective lenses, 4X, 10X, and 40X. Better microscopes usually include a fourth, 100X, objective lens. The overall magnification of the microscope is the product of the objective lens magnification factor and the eyepiece (ocular) magnification factor. So, for example, if your microscope has a 10X eyepiece and 4X, 10X, and 40X objectives, your available magnifications are 40X, 100X, and 400X. If you also have a 100X objective, you also have 1000X magnification available. If you replace the standard 10X eyepiece with a 15X eyepiece, your available magnifications become 60X, 150X, 600X, and 1500X, which is about the maximum magnification usable with an optical microscope.

Microscope objective lenses differ in two major respects, color correction and flatness of field.

Color correction

The level of color correction is specified as either achromatic or apochromatic. Achromatic lenses are corrected for chromatic aberration at two specific wavelengths of light, usually red and green. An achromat brings those two wavelengths to the same focus, with other wavelengths very slightly out of focus. An apochromat is corrected for three specific wavelengths of light–usually red, green, and blue–and brings those three wavelengths to the same focus, providing slightly sharper images than an achromat. Apochromatic objectives are extremely expensive, some costing more than $10,000, and are found only on professional-grade microscopes. Any microscope affordable for a home lab uses achromatic objectives.

Flatness of field

Standard objectives have limited correction for spherical aberration, which means that only the central 60% to 70% of the field of view is in acceptably sharp focus. Semi-plan objectives have additional correction that extends the sharp focus area to the central 75% to 90% of the field of view. Plan objectives extend the area of sharp focus to 90% or more of the field. This additional correction for flatness of field is completely independent of color correction. You can, for example, buy semi-plan apochromatic objectives and plan achromat objectives.

Finally, some vendors offer optional upgrades to superior lens coatings, often under such names as Super High Contrast or something similar. These superior coatings don’t improve color correction or flatness of field, but they increase image contrast noticeably.

For most home lab use, ordinary achromatic objectives provide perfectly acceptable images and are by far the least expensive choice. My own microscope, a Model 161 dual-head unit shown in Figure 3, has the upgraded ASC objectives, which I purchased because I planned to do a lot of photography through the microscope. Otherwise, I’d have bought the standard achromatic objectives.

Parfocality and Parcentrality

All but toy microscopes are parfocal and parcentered. Parfocal means that all objectives have the same focus. When you focus a specimen at 40X, for example, and then change to 100X, the specimen remains focused. (You may have to touch up the focus with the fine-focus knob, but the focus should be very close to start with.) Parcentered means that if you have an object centered in the field of view with one objective and you change to a different objective, the object remains centered in the field of view. Professional-grade microscopes provide adjustments for both parfocality and parcentrality, but student- and hobbyist-grade microscopes are set at the factory and cannot be adjusted by the user. That means it’s important to check these settings as soon as you open the box of your new microscope.

To check parfocality, place a flat specimen (a thin-section or smear slide is good, if you have one; otherwise any flat specimen) on the stage and focus critically on it at the lowest magnification. Then change to your next highest magnification and check the focus. It should be in focus or nearly so, requiring at most a partial turn of the fine-focus knob to bring it into critical focus. Change to your next higher magnification and again check the focus. Again, it should require at most a small tweak with the fine-focus knob to bring the specimen into sharp focus.

To check parcentrality, center an object in the field of view at the lowest magnification and then switch objectives to the next-higher magnification. The object should remain centered, or nearly so. Repeat until you are viewing the object at your highest magnification. Because it’s easier to judge whether an object is centered at high magnification, center the object at your highest magnification and then work your way down to lower magnifications. If the object remains centered (or nearly so), your parcentrality is acceptable. If the position of the object in the field of view shifts dramatically when you change objectives, the parcentrality is off. The only solution is to return the microscope for a replacement. (All of the scopes sold by Maker Shed are manually checked for parfocality and parcentrality before shipping and should be fine unless they are damaged in shipping, which very rarely happens.)

The ocular (or eyepiece) magnifies and focuses the image provided by the objective lens and presents it to your eye. Standard microscope ocular barrels are either 23.2 mm (usually abbreviated to 23 mm) or 30 mm in diameter, which means it’s easy to exchange oculars if you need a different magnification range. The standard ocular magnification factor is 10X, but 15X oculars are readily available to increase the range of magnifications available to you. Avoid zoom oculars, which invariably produce inferior images.

Most toy microscopes have single-element oculars, sometimes made of plastic, that provide a distorted, dim, narrow view. Better microscopes, including all of the models offered by Maker Shed, provide multi-element optical glass oculars that provide a flat, bright, wide field of view with minimal distortion.

Most standard oculars are unobstructed, but some have a standard or optional pointer or reticle (grid or graduated scale). A pointer is primarily useful in a teaching or collaborative environment, where one person can place the pointer on an object of interest so that the other person can identify it unambiguously. A graduated reticle is useful in biology and forensics for measuring the size of objects in the field of view, and a grid reticle is useful for counting large numbers of small objects in the field of view.

Focusing

Microscopes use one of two methods for focusing. Most older models and some current models keep the stage in fixed position and move the head up and down to achieve focus. Most current models and some older models reverse this, keeping the head in a fixed position and moving the stage up and down to achieve focus. Either method works well.

Toy microscopes and the least expensive hobby/school models have a single focus knob that changes focus at intermediate rate, which makes it difficult to achieve critical focus. Midrange models have separate coarse-focus and fine-focus knobs. More expensive models usually have a coaxial focus knob, often one one each side of the microscope, with the coarse focus on the outer knob and the fine focus on the inner knob, as shown in Figure 5.

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Figure 5. Coaxial focusing knob, with coarse focus (outer ring) and fine focus

You use the coarse-focus knob to bring the specimen into reasonably close focus, and then use the fine-focus knob to tweak the focus slightly to achieve the sharpest possible focus. If you are viewing a three-dimensional object, particularly at higher magnifications, you’ll find that you can’t bring the entire depth of the object into focus at the same time. You use the fine-focus knob to adjust focus slightly as you’re viewing the object to view different “slices” of it in depth.

Many coaxial focus knobs, including the one in Figure 5, provide a graduated scale. One obvious use for this scale is in a collaborative situation. One person can focus critically, note the scale setting, and then turn over the microscope to the second person, who refocuses as necessary. When the first person returns to the eyepiece, merely resetting the scale to the original value puts the specimen back into critical focus. A less obvious use of the graduated scale is to determine relative depths of parts of a specimen. By setting a baseline focus on one level of the specimen and then noting how much change in scale units is needed to refocus on parts of the specimen at different depths, you can get a relative idea of the differences in depth of different parts of the specimen.

Mechanical Stage

Inexpensive microscopes use a pair of clips to secure the microscope slide to the stage. Although workable at low magnifications, this method becomes increasingly difficult as you increase magnification. The problem is that a very small movement of the microscope slide translates into a huge movement in the field of view. At low magnification, the smallest movement you can make manually may move an object from one side of the field of view to the other. At higher magnifications, the smallest movement you can make manually may move the object completely out of the field of view. If you’re viewing a living, moving object (such as a paramecium), it can be almost impossible to keep the object in the field of view.

The solution to this problem is a mechanical stage, shown in Figure 6. With a mechanical stage, you clamp the slide into an assembly that provides rack-and-pinion gearing that allows you to turn knobs to move the slide continuously along the X-axis (left or right) and the Y-axis (toward or away from you) in extremely small small increments.

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Figure 6. A typical mechanical stage (note the verniers on the X and Y axes and the top lens of the Abbe condenser below the stage)

Centering an object becomes trivially easy, as does keeping a moving object in the field of view. Because the mechanical stage provides X-axis and Y-axis verniers, it’s easy to return to a specific location on the slide even after you’ve moved it completely outside the field of view. We wouldn’t even consider using a microscope without a mechanical stage. Life is too short.

Substage Components

Despite the fact that they’re located below the stage (and therefore below the specimen), two substage components have a significant effect on image quality.

Diaphragm

The diaphragm is used to control the diameter of the light cone where it intersects the specimen being viewed. Ideally, you want the diameter of the light cone to be the same size as the field of view of the objective lens you’re using. At low magnification, where the field of view is relatively large, you want a larger light cone; at higher magnification, where the field of view becomes correspondingly smaller, you want a smaller light cone. If the light cone is smaller than the field of view, the field is not completely illuminated. If the light cone is larger than the field of view, “waste” light from outside the field of view reduces contrast and image quality.

Toy microscopes have no diaphragm. Basic models have a disc diaphragm, which is simply a metal disc with several (usually five or six) holes of different diameter that can be rotated into position. Disc diaphragms provide only compromise settings, but are generally quite usable. Better microscopes have iris diaphragms, which can be set continuously to provide any size of aperture, from a pinhole to wide open.

Condenser

The condenser sits between the diaphragm and the stage, focusing light from illuminator onto the specimen to provide a brighter, sharper image. Toy microscopes and entry-level student/hobbyist microscopes have no condenser. Somewhat better microscopes use a simple fixed-focus condenser, usually rated at 0.65 NA (Numerical Aperture, where the NA of the condensor must be at least as high as the NA of the objective lenses it is to be used with. A 0.65 NA condenser can be used with at most a 40X objective. Oil-immersion 100X objectives with a 1.25 NA rating require a 1.25 NA condenser.) Midrange microscopes use a focusable Abbe condenser, usually of 0.65 NA and usually with a spiral focusing arrangement. Better models provide a rack-and-pinion focusable Abbe condenser with a 1.25 NA for use with any objective up to a 100X oil-immersion objective.

Köhler Illumination

If you pick up any book on basic microscopy, you’ll soon encounter the term Köhler illumination. Devised by August Köhler in 1893, this illumination method provides extremely even illumination and the highest possible contrast. Unfortunately, setting up Köhler illumination requires physical features not present on affordable scopes, including a positionable lamp and a focusable lamp condenser. Very few microscopes under $1,000 include the features needed to set up Köhler illumination.

Fortunately, the alternative, called critical illumination, is perfectly usable for most visual work. (In fact, many experienced microscopists prefer critical illumination to Köhler illumination for visual work at high magnification.) The extreme evenness of Köhler illumination is important for professional quality results when you shoot images through a microscope, but otherwise critical illumination works fine.

The Final Decision

So, with all of that said, which model should you get? Obviously, that depends on both your needs and your budget, but we can offer some advice to help you make a good decision.

Entry Level 400X microscope:
It’s as easy to spend too little on a microscope as it is to spend too much. We suggest you avoid toy microscopes entirely. They’re a waste of money. If you need a basic 400X scope at minimal cost, choose the Maker Shed Model 109. This scope is perfect for undemanding hobby use or for elementary school students, and in a pinch, can serve through middle school. At $119, it lacks a mechanical stage and provides only basic features, but the optics and mechanicals are solid.

Midrange 400X scope:
If you need a midrange 400X scope, choose the Maker Shed Model 131. This scope is good for hobby use, and can serve a student from middle school or junior high school through high school, excepting AP biology. At $235 this scope provides very good optics and mechanicals. The only major missing feature is the 100X oil-immersion objective, which is needed for cell biology studies in high school AP biology courses.

Entry Level 1000X scope:
If you need an entry-level 1000X scope, choose the Maker Shed Model 134. This scope is excellent for hobby use, and is the only scope a student will need from middle school or junior high school through high school AP biology. At $359, this scope provides very good optics and mechanicals, and is essentially a Model 131 upgraded to include a 100X oil immersion objective, a focusable 1.25 NA Abbe condenser, an iris diaphragm, and a standard mechanical stage.

“Lifetime” 1000X scope:
If you want to make your first microscope purchase your last, choose one of the Maker Shed 160-series models, the $479 Model 160 (monocular), $539 Model 161 (dual-head), $629 Model 162 (binocular), or $819 Model 163 trinocular). You can pay a lot more for a microscope, of course, but the only major feature missing from the 160-series scopes is support for Köhler illumination. Any of the 160-series microscopes is a superb choice for hobby use, and is the only scope a student will need from middle school or junior high school all the way through university and graduate school. The optics and mechanicals are excellent, and the feature list is impressive. Even people who use professional-grade microscopes every day are invariably stunned by the level of mechanical and optical quality the 160-series microscopes provide at this price point. The only upgrades we offer on these scopes are the ASC (high contrast) or plan achromatic objectives.

In the Maker Shed:
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Check out all the great microscopes that we now carry in the Maker Shed. We will be adding a lot more tools, chemicals, and chemistry sets over the next few weeks leading up to the big Make: Science Room launch, so keep an eye out on Make: Online for all the latest announcements!

68 thoughts on “Make: Science Room – Choosing a microscope

  1. If “Science Room” is to be taken seriously at all, you may want to reconsider sentences like this:

    “Ask any scientist to name the single most important tool for scientific study. Chances are, the answer will be a microscope.”

    I don’t think this statement is even true. I’m not saying that it isn’t one of the most important tools. I’m just saying that if you ask every scientist, “What is the single most important tool for scientific study?” that I believe that the most popular answer will not be “a microscope”.

    I’m not sure what the most popular answer would be, but I am inclined to think that some variation of “a critical mind” would outrank microscope, at the very least.

    Anyways, the fact that the author starts his article with a weaselly-worded bare assertion really takes away from the rest of the article, especially because it’s supposed to be about “science”. The worst part is that we know the author just made up this fact because if he got the data from some actual research, he would have said “In 200x, so-and-so asked 1000 scientists to name the scientist’s most important bench tool, and the most common answer was ‘a microscope’.”

    Anyways, a little more editing in the future would be appreciated.

    1. The most important thing to a scientist is a fellowship/ grant money!
      Then free labor (interns/ grad students)
      Then I guess a microscope. The bunsen burner comes close.

      Kidding aside, I got my first microscope in 3rd grade and it opened up the world for me.

      1. Mr. Ridiculous

        Grant Money? That is an interesting topic, and it will help you purchase a great scope!

        I am going to ask Bob for some insight (and maybe a post) on that subject. Thanks.

    2. If we are going to go that route, then I guess breathable air is #1 on my list, or potable water. :)

      On a serious note, this article contains a lot of great advice for picking out a microscope, even if it isn’t *your* most important piece of equipment.

      1. How is breathe-able air a tool for science?

        Your reply doesn’t show any evidence of reason. It ranks right up there in the “Oh yeah?!” category of discourse.

        To put it simply, air is an environment, not a tool. It’s like saying that water is a tool for swimming. It doesn’t make sense.

        Well, whatever, I made a critique and it has been ignored. When you try something new, you should expect feedback from people who have interest in that field.

  2. This is a mind-bogglingly timely article, considering that after years of trying I’ve finally reached the point of being able to buy a real microscope for some skilled-amateur microbiology.

    The one “special” feature I’d like to have access to is a darkfield condenser for examining and photographing “stainless” live cultures (there’s no way I’ll be able to afford phase-contrast microscopy equipment any time soon). Are there such condensers available for the “Maker Shed” microscopes that I could swap in and out with the regular Abbe condenser?

    Also – any suggestions as to good places to get other microscopy supplies (slides, stains, etc.)?

    (I’m guessing “joe” up there is into physics, since I think it’s the only major branch of science that’s unable to make much use of microscopes – even chemists like to examine the structures of their purified chemical crystals once in a while.)

    1. With regard to darkfield microscopy, there’s no need to spend much money to get good results. I do darkfield microscopy on my Model 161 using an accessory I made in about five minutes at a total cost of less than ten cents.

      All you need is a flat microscope slide and some opaque circles of various sizes stuck to the slide. I used various hole punches and some thin card stock and glued the circles to the slide with my wife’s colorless nail polish. You could also use the little stick-on circles sold in sheets at Staples and similar vendors.

      The trick is to get the opaque circles as close as possible to the bottom of the condenser lens. My Model 161 has a swing-out filter holder that’s perfect for the purpose. I found that there wasn’t quite enough clearance between the top of the filter holder and the bottom of the condenser assembly for a standard glass slide to fit, so I used a very thin plastic slide. It fits perfectly. Not quite a friction fit, but almost.

      In use, simply set things up to get a good view with normal illumination and then slide the slide into that gap until you have one of the circular spots centered under the condenser. (You’ll want various sizes to allow you to use an occulting circle just barely smaller than the iris opening.

      This method should also work pretty well with the 131 or 134 scopes, although I haven’t tried it.

      As far as phase contrast, our distributor does carry a couple models that offer it, but the least expensive sells for $1,500+, which is really out of the price range we wanted to focus on.

      1. Oh, yeah. As to your question about supplies, check back once the Make: Science Room launches on 17 August. We’ll be offering a pretty broad range of slides, cover slips, mounting fluids, stains, and so on.

        Maybe not immediately at launch, but very soon thereafter we should have several kits available, including a Microscope Starter Kit, a Basic Microscopy Staining Kit, and an Advanced Microscopy Staining Kit.

  3. THAT’s your take-away from this article? That the “critical mind” should be pointed out as a more important “tool” than a microscope?

    Are you a scientist, Joe? BESIDES your wetware, and all of the obviously critical uses of it in the discipline of science, what would you say is the single most important ACTUAL tool?

    1. I’m with Mr. R.

      I’m not a scientist, but I work with scientists in a science environment. My husband IS a scientist.

      Neither of uses a microscope. My most important tool is a computer; I’m sure he’d say the same. All of our data comes from telescopes – his mostly ground-based, mine mostly in orbit.

      Microscopes are important, to be sure. What’s bothering us is the naked assertion that they are the MOST important tool. That one phrase made this otherwise helpful article feel more like a HuffPo “medical” column.

      1. @joe and gfireman – since you’re both science minded you’ll both agree that this statement is correct…

        “Ask any scientist to name the single most important tool for scientific study. Chances are, the answer will be a microscope”

        “chances are” is accurate.

        perhaps not the best choice or words, but “chances are” works. there’s also a chance i’ll fall through my chair or explode too, that would be interesting.

        bob is chemist so maybe he hangs with a different crowd. i think a microscope is an iconic symbol of an important tool in science, just like a telescope – both (now) require a computer and a critical mind of course. we also need “math” and other pesky things.

        if you’d like to write an article about “best computers” for scientists, please do – or (joe) if you’d like to write an article about best resources for “a critical mind” also – please do, join in – we’re losing the war, we need your help.

        otherwise, i think you’re hijacking a great article that bob spent a lot of time on called “choosing a microscope”. comparing this to a huffpo article is really unfair and just mean – leave the politics there.

        i think it’s fair to ask that you consider contributing a little more constructively – it’s a lot of effort to write something you won’t see on *any other site* – who else is spending the time and resources on anything close to this online?

        it’s a lot easier to write about picking the latest and greatest iphone apps, top 10 lists of HOT GADGETS, you know – important stuff :)

        1. http://en.wikipedia.org/wiki/Weasel_word

          No, I do not agree with your assertion that chances are is correct. It is only correct if you ignore the connotation of the words. Your statement is reminiscent of calling a man who didn’t know his father a bastard. Yes, it’s technically what he is, but “bastard” has additional meaning, and it is not completely honest in this context.

          “chances are” is an example of “weasel words”, which are specifically used for disingenuity, specifically when you try to make people think that you know what you’re talking about when you don’t.

          I guess in your world, it is okay to mislead people as long as you don’t technically lie.

  4. This is a great run-down. I have actually worked in the microscope business (manufacturer, distributor) and if I still did, I would steal this clear, comprehensive article and repurpose it for my own marketing materials.

    I will say this — I imagine that, like me, a lot of readers on here have kids that they are subtly or not-so-subtly trying to program as scientists / engineers. A stereo microscope is an amazing thing for kids. Bugs, pollen etc are just unreal. And yes, the cheap digital microscopes QX4 etc are indded toys. But they are fun toys that connect quickly and easily to a computer and make imaging really easy. Don’t discount them out of hand as a great intro.

  5. Great, I spent all morning researching how to build my own Dobsonian telescope. Now I find myself wanting a microscope. Science is bankrupting me!

    1. Me, too. ;) I also have several telescopes–not to mention binoculars–and have written a couple of books on astronomy.

      As much as I love using both, if I had to pick having only a telescope or only a microscope, I’d choose the latter. With a telescope, my wife and I mostly pursue DSOs, which means we need a clear night with no moon, and have to drive 25 miles or more to get to a site away from city lights. Full darkness doesn’t arrive until about 10:00 p.m. this time of year, so by the time we get in even a couple of hours observing and then tear down, pack up and drive home, it’s after 1:00 a.m.. In practical terms, that means we can observe only on Friday or Saturday nights, and the number of clear, moonless Friday and Saturday nights is limited.

      With a microscope, on the other hand, time of day and weather are immaterial. So, my advice is if you have to choose one or the other, go with the microscope, at least at first. You’ll get more use out of it.

  6. Weaselly-worded bare assertion? Naked assertion? Come on, folks. All I wrote was “chances are”, and indeed that’s been my experience. I did a casual survey among a two or three dozen of my scientist friends–from physicists and astronomers to chemists to biologists and geologists–usually during general conversations. I asked them “If you had to pick one tool as the single most important to science, which would it be?” Sure, I got a couple who answered the telescope, and I think one chose the computer. But at least two out of three chose the microscope initially, and a couple changed their votes immediately when I mentioned the microscope.

    Incidentally “a critical mind” racked up zero votes.

    1. Hi Bob, I really enjoyed your article and please don’t let a few nitpicking comments get you down. I’ve written tutorials like these and I know how long it takes, and the anxiety of being technically accurate & maintaining the reader’s interest.

      Personally, when I first played with the microscope at a young age I was sure I’d be a scientist. That led to basic chemistry set, then tinkering with electronics, and eventually computers and BBS at age 11. Life took some strange twists and turns and eventually got a liberal arts degree some years ago (heck, my brother finished grad school and became a physicist). The microscope will always be close to me as the catalyst that started it all, and it’ll always bring me back to my childhood.

      And when I have kids of my own (won’t be too long now :)) I’ll make sure they’ll read this guide before buying a microscope. Hey, maybe you can post some microscope images at different magnifications?

      As an aside, I really wish I’d known about the ‘Warranty Voider’ Leatherman months ago, but unfortunately those funds went to a dept store. :/ But now I know where to buy gifts for the rest of my family :)

      1. Thanks for the kind words. No, I don’t let negative comments bother me. I’ve been writing books and maintaining a blog for more than a decade, and I soon learned that some people seem compelled to pick apart anything they read even if they can find only trivialities to focus upon.

        As to the stereo microscope, I have no expertise in SMT/SMD, but obviously a stereo microscope is useful for many other purposes. I’m looking at several models right now for possible inclusion in the Maker Shed.

        Why not write an SMT/SMD article yourself and submit it for publication here?

    2. Let me be frank:

      I don’t believe you. I don’t believe you asked dozens of your scientist friends that question. You want me to believe that you asked dozens of your friends the same stilted sounding question just so that you could use the vague phrase “chances are” in your article? Really?

      Let me go back and dissect your comment. You started with, “All I wrote was “chances are”, and indeed that’s been my experience.” This is very broad. It’s been your experience. That’s your first answer.

      “I did a casual survey among a two or three dozen of my scientist friends–from physicists and astronomers to chemists to biologists and geologists–usually during general conversations.” Now, you’ve actually done a casual survey. That’s your second answer.

      “I asked them “If you had to pick one tool as the single most important to science, which would it be?”” Now, you’re stating that you asked them all a very specific question, which specifically proves your point. That’s your third answer.

      “Sure, I got a couple who answered the telescope, and I think one chose the computer. But at least two out of three chose the microscope initially, and a couple changed their votes immediately when I mentioned the microscope.” OK, you remembered to ask the specific question, but you can’t say for sure how many chose the computer? If you’re not going to bother remembering their answers, then why would you ask them the question?

      “Incidentally “a critical mind” racked up zero votes.” Cheap shot at me.

      So, your comment reads exactly like somebody who knows he is wrong, but can’t admit it. As you spin your tale, it gets more and more specific, until, yes, you’ve actually specifically proven me wrong, albeit not in any scientific way. Let me contrast that with how honest people respond.

      It would *start* with something like, “Actually, I did a survey of my scientist friends, …” Nobody in the world would start off responding to a specific point with such a vague response. It’s unnatural.

      Ending with a cheap shot is classic as well. As long as you have the credibility from your story, it’s the perfect time to impugn on the credibility of the other side.

      My original complaint was that the article had a highly unscientific tone and used weasel words when the subject was supposed to be about science. From my perspective, your response seems worse than the original offense. Of course, I could be mistaken. Even if your comment was literally true, it doesn’t make the introduction of your article correct or my critique less valid. It does mean that you got dressed down by an anonymous commenter on the Internet. For whatever that’s worth…

  7. The important thing to remember about blogs, is you don’t have to read the article to make a comment. You only have to read the first couple sentences of the intro and comment on that.

    It’s a real time saver.

  8. Yeah, I gotta say, given how hard we’ve worked on the Make: Science Room, how hard Bob has worked, how wonderful and thoughtful an intro to microscopes I think he wrote, to have it summarily dismissed because of that one “chances are” sentence is a serious buzz-kill. But whatever. We’ll power through. If nothing else, we’re entertaining ourselves…

  9. seriously, nuke bad comments, those two aren’t so bad – but they’re close.

    sites should be able to encourage the kind of discussion that they want – as opposed to a couple folks randomly popping in and setting a new undesired tone. they really damage what MAKE is trying to do with articles like this, why give them what they want?

    comments should:
    -add information, or
    -be a well-reasoned critique

    comments should not be:
    -spam, attacks on people, or
    -anything the editors do not like

    one or two trolls will complain, but they will eventually move on or some may even reconsider their role in this universe and contribute, chances are :)

    back to scopes’ nice article bob, keep them coming.

    gareth, can you post that cool graphic in the flickr pool and other places? big version, it’s awesome.

  10. I found this line tantalizing:

    > I planned to do a lot of photography through the microscope.

    Have you done that successfully with the 161? What kind of adapters are needed (the makershed page also makes only brief mention of the use of the secondary eyepiece for imaging…) Perhaps that would make a good follow-on article, especially with a lot of sample pictures :-)

    (I had a “toy” microscope as a kid, which did have one significant value – it made the fantastic photomicrographs that showed up on NOVA and other science TV a little more believable :-)

    1. Yes, I’ve shot a lot of images with the Model 161, both for personal use and for the not-yet-published _Illustrated Guide to Home Forensics Investigations_. To summarize, shooting images through a microscope is easy. Shooting good images through a microscope is very difficult.

      For basic imaging, you can simply use a cardboard tube between the microscope ocular and the lens of a digital camera. You’ll have to play around with zoom and focusing, but it’s relatively easy to get some usable images that way.

      For publication purposes, I needed better images, so I ended up buying an adapter from Edmund Scientific for about $100. It has a KA mount on one end that fits our Pentax DSLRs and a tube on the other end that fits over the vertical eyepiece tube on our Model 161.

      Focusing and camera movement are both issues, so what I ended up doing was setting the illuminator to its brightest setting and the iris wide open for focusing. Once the image is focused, I close down the iris to the appropriate setting and dim the illuminator far enough that I can use an exposure of at least a couple of seconds. (That way, any blurring from camera movement or mirror slap is minimized.)

      Even at that, critical focusing is difficult, so I generally shoot several images, tweaking the fine focus in small steps first in one direction from what I judged to be proper focus and then in the other direction. I generally end up with a dozen or so images, from which I can pick the best one.

      And even then, the camera is much less forgiving than the eye. I’ve found that even the best image I can shoot through the microscope is considerably less appealing visually than the actual live image viewed by eye.

  11. While I hate to be one of these dorks posting complaints, I do strenuously disagree with *most* of the statements in the introduction.

    I’m not sure that I personally would name a microscope as one of the most important research tools today. Historically, yes. But none of the labs that I have ever worked in has had one (that I can recall), and the only use I have for a microscope these days is for soldering tiny parts, and that’s certainly not a scientific application. This sort of assertion reminds me of a list that I saw some years ago listing “the most important questions in science,” but was *really* a list of the most important questions in particle physics. Maybe you– and your two or three dozen scientist friends –would have seen that list as a little biased too.

    The statement that “Without a microscope, we are limited to what we can see with the naked eye” is overreaching. I have a voltmeter, and I’ve used a telescope, oscilloscope, audio frequency counter, and logic analyzer. I’ve captured a single atom, and I didn’t use a microscope to do see that it was there. That’s what’s great about scientific tools– nearly all of them allow you to see things that you couldn’t otherwise.

    Anyway, this list looks useful, but the single most surprising thing to me is the base assumption that there’s only one type of “useful” microscope. These are all traditional “professional laboratory” styled chemistry and biology oriented light microscopes. That’s only one type out of many different microscopes. (And if I had to choose one type of microscope to own, that wouldn’t be the one.) Discounting all of the modern CCD-based microscopes (even the professional ones) as “toy models” doesn’t seem reasonable to me. And that’s not even counting the dozens of other microscopes– STM, SEM, TEM, NSOM, AFM, and on and on that are in the modern scientists arsenal. Many of these can be made by a talented maker in the $1500 range.

    So… there’s *a lot* of good stuff in the article, but it’s pretty specific to a certain type of microscopes, and it might be worth recognizing that people do science in other ways as well.

  12. I recently got myself a stereo boom microscope for SMD soldering. Unfortunately I couldn’t find any real recommendations on the net in regards of suitable magnifications factors or if zoom is a requirement.

    I ended up buying a 10x/20x from eBay for $179 but now I wish that I’ve dropped some more money on it and gotten a 5-30x zoom instead…. Still – 10x fixed is a so much better than one of the “magnifying lamps” that I’ve used before :)

    I’d have liked to see an article as exhaustive as this on the art of selecting a good ‘scope for SMT/SMD works before I bought mine.

    Maybe someone with expertise in the subject can bake a nice writeup for Make?

  13. “The statement that “Without a microscope, we are limited to what we can see with the naked eye” is overreaching. I have a voltmeter, and I’ve used a telescope, oscilloscope, audio frequency counter, and logic analyzer.”

    Well, to be pedantic, none of the instruments you mention other than the telescope operate on visible light, so they allow us to “see” only in the sense that they translate phenomena into visual forms.

    “Anyway, this list looks useful, but the single most surprising thing to me is the base assumption that there’s only one type of “useful” microscope. These are all traditional “professional laboratory” styled chemistry and biology oriented light microscopes. That’s only one type out of many different microscopes. (And if I had to choose one type of microscope to own, that wouldn’t be the one.)”

    Eh? The only comment I made about “useful” was to say that a compound optical microscope was the most useful type for a *home scientist*, and that a stereo microscope was the second most useful type. Surely you can’t disagree with that statement? At no point did I say that other types of microscopes weren’t “useful”.

    “Discounting all of the modern CCD-based microscopes (even the professional ones) as “toy models” doesn’t seem reasonable to me.”

    Again, eh? Where did I discount CCD-based microscopes, and particularly professional models, as toys? The comment I made about toy microscopes was in reference to $25 models. Surely, you don’t dispute my characterization of those as toys?

    “And that’s not even counting the dozens of other microscopes– STM, SEM, TEM, NSOM, AFM, and on and on that are in the modern scientists arsenal. Many of these can be made by a talented maker in the $1500 range.”

    But not in home scientists’ arsenals, which is the topic of this article. If you can really make a useful scanning electron microscope for $1,500, I’m impressed. I don’t know how to do that. Why not build one or more of these models yourself and write up an article for MAKE? It’d be a killer article, and I’m sure the editors would jump at the chance to publish it.

    “So… there’s *a lot* of good stuff in the article, but it’s pretty specific to a certain type of microscopes, and it might be worth recognizing that people do science in other ways as well.”

    Well of course it’s specific to a certain type of microscope–those that are affordable and practical for the home scientists who read this article. That was the purpose of the article, to tell them what to look for in a home microscope, what matters and what doesn’t. I would have thought it obvious that this article wasn’t intended to provide advice to professional scientists.

  14. >Eh? The only comment I made about “useful” was to say that a compound optical
    >microscope was the most useful type for a *home scientist*, and that a stereo >microscope
    >was the second most useful type. Surely you can’t disagree with that statement?

    Actually, I can. I am entitled to have whatever opinion that I like.

    > At no point did I say that other types of microscopes weren’t “useful”.

    You did say “two types of microscopes are useful in home science labs,” which does broadly discount all the other types for home use. Unnecessarily, in my opinion.

    >Where did I discount CCD-based microscopes, and particularly professional models, as toys?

    You say that you focus on “high-quality microscopes,” as opposed to “toy” microscopes, and they are not in the list of “high-quality microscopes.” That seems clear enough….

    > Surely, you don’t dispute my characterization of those as toys?

    I was not taking issue with that characterization before, but now that you bring it up, I must say that I do fundamentally disagree with you on this. Many of our cheap microscopes, if brought to the developing world, could be extremely important, life-saving tools. Our $25 microscopes today are better in every sense than Leeuwenhoek’s, which changed the world.

    In my opinion it is harmful, not helpful– in any field– to refer to low-end tools as “toys.” Just because your computer isn’t on the top-500 supercomputer list doesn’t make it a toy. The quality of science that is done with a nicer microscope isn’t necessarily better.

    >Why not build one or more of these models yourself
    >and write up an article for MAKE?

    Slightly tempting, but microscopy isn’t one of the topics that I really want to spend my time on. I am working on several other big projects, some of which may indeed result in more articles in MAKE.

    Besides which, I’m not an expert; there are already enough homebrew microscope projects out there. If you’re serious, then why not ask one or more of the people who did those projects to write an article?

    http://tinyurl.com/n9kq6p
    http://www.geocities.com/spm_stm/Project_overview.html
    http://www.e-basteln.de/
    http://tinyurl.com/myk6k8
    http://www.microscopy-uk.org.uk/mag/artapr01/rhtem.html
    http://tinyurl.com/mewsev
    http://tinyurl.com/nj7wp3

    (If I were going to do this, I might just build a kit: http://sxm4.uni-muenster.de/stm%2Den/ )

    >Well of course it’s specific to a certain type of microscope [….]

    No, that *does not* follow naturally from anything that you wrote, which is why I left the comment in the first place. Your article was titled “Choosing a Microscope.” Your intro talks about science as a whole– as broad as physics versus forensics. And yet you focused on a very specific type of microscope– the type that *you* think of when someone says “microscope.” Yours is a valid perspective. However, I believe that I was justified in pointing out that a lengthly, ambitious article like yours might have benefitted from an introduction that acknowledges the existence of other types of microscopes.

  15. I initially didn’t read this article because I’m not in the market for a microscope, but when the comment count went up, I had to find out what the fuss was about. And the fuss is really about how you address your readers. You must know by now that makers are intensely passionate about what they do and make, and that exclusionary language and broad generalizations, even when unintentional, will make them react. Have more respect for them and avoid assumptions about them and they’ll love you, or at least leave you in peace.

    Having read the article, and checked out the offerings in the Maker Shed I found it interesting that no one mentioned how much this article seems like an ad. Now, I have no problem with pimping your own products in your blog, but maybe this wouldn’t have caused nearly so much quibbling if you had been more straightforward. I think no one would have complained if this had been the article opener:

    “Check it out! Maker Shed is now selling microscopes. We wanted to get low cost, high quality tools in the hands of makers. Here’s how we chose our offerings, and here’s a guide to how to pick the right one for you.”

    Thanks for the shopping guide – I’ll come back to it if I ever decide I need a new microscope. And now that you’ve got me somewhat interested in looking at small things, I’m going to check out this $20 eyeclops we picked up at the toy store.

  16. > “Ask any scientist to name the single most
    > important tool for scientific study. Chances
    > are, the answer will be a microscope”

    > “chances are” is accurate.

    > perhaps not the best choice or words, but “chances
    > are” works. there’s also a chance i’ll fall through
    > my chair or explode too, that would be interesting.

    I can understand that you want to defend Marc, but how about the statement: “Chances are you are a complete and total idiot” which is also a correct statement, by your rules. Your defense did little to convince me that your re-definition of “chances are” is appropriate and more to convince me that anything the Make editors writes is beyond reproach.

    “And the fuss is really about how you address your readers. You must know by now that makers are intensely passionate about what they do and make, and that exclusionary language and broad generalizations, even when unintentional, will make them react. Have more respect for them and avoid assumptions about them and they’ll love you, or at least leave you in peace.”

    There! You seem to have a very good grasp of the situation an are able make a helpful, non-demeaning post. You I would hire as a web blog editor.

  17. For a number of decades, the oscilloscope was the most important tool in a physics laboratory. It’s a portable, secondary-reference calibration source for voltage, current, and time. Time-based measurements to this day still have the greatest accuracy of any physical measurement. If you want a really precise measurement, figure out how to convert it into a time-based measurement. If you disbelieve this, consider that the unit of length is now defined by means of a particular frequency, a time-based reference which, in practical terms, requires frequency stability for accurately measuring length. So you start by making a single-frequency source (time) and use interferometry to convert this into length.

  18. Hey nice information received from this post. I feel it will be easy to search a microscope with this information.

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