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Posts tagged ‘microscopes’

Spectrum Scientifics Microscope Buyer’s Guide – REPOST

The holidays have us pretty busy, so here is our Microscope Buyer’s guide for those seeking to buy one!

Spectrum Scientifics Microscope Buyers Guide

Congratulations! You’ve decided to buy a microscope! A microscope is a wonderful instrument that can fascinate kids and adults alike. With proper care, a microscope can last a lifetime. But buying a microscope can be confusing for the first time buyer. There are so many different designs, it can be a bit overwhelming. This guide should help you make the proper choice in deciding on a microscope model.

First let’s start by discussing the different designs of microscope. We will break microscopes into three different categories: Compound Microscopes , Inspection/Dissection Microscopes, and ‘Other’. We’ll cover these one by one.

Compound/Biological Microscopes : Compound (or Biological) microscopes are the models designed to be used with slides. They are high powered; using multiple objective lenses (the lenses that point at the slide) to typically provide 40X, 100X, 400X and sometimes 1000X right off the shelf. Modern compound microscopes usually have some sort of illumination from below to light up the slide. Depending on the design of the compound microscope it may have features like binocular eyepieces (two eyepieces, but do not provide stereo vision) a mechanical stage for moving the slide easily, coarse and fine focus (for easy focusing) and different lighting designs.

The disadvantage of a compound microscope is that you pretty much must use it with slides. You can’t just plop a bug, coin, or plant leaf onto the microscope and expect to get a decent image. Compounds aren’t designed to do that. You can cut up the leaf/bug/whatever and make it into a slide with some effort and a slide-making kit, but that does take some time and only lets you view s small part of the the found object.

Inspection/Dissection Microscopes: Inspection/Dissection microscopes are designed to be used with any object you can fit on the microscope’s staging area. This can be coins, stamps, bugs, plant parts, circuit boards, small animals, or whatever else you might find. Inspection Microscopes often have much lower magnification (10x-40x is typical), much wider viewing fields, and very often the binocular versions give true stereo vision. This allows the viewer to ‘work’ (I.e. dissect) on the object being viewed and get a true sense of depth of objects like coins. Inspection Microscopes may have only 1-2 levels of magnification verses the 3-4 on compound microscopes. The microscope will also have top-down lighting, and some may have bottom-up lighting as well. The eyepieces used in many mid-range inspection microscopes are often larger and more comfortable to use.

The disadvantage of a compound microscope is that its magnification is very low and you cannot use it with slides. That means if you want to see cells, bacteria, or other very tiny objects you will need to get a compound microscope as well.

As you can tell from these write-ups, these two designs are very different from each other. Before we discuss the third category, let’s compare and contrast these two designs:

Features: Compound Microscopes vs. Inspection/Dissection Microscopes

Compound Inspection/Dissection
Magnification High: 40x and up Low: 10-40x typical
Levels of Magnification 3, sometimes 4 (40x, 100x 400x typical) 1 or 2*
Lighting From Bottom From top (or top and bottom)
Viewing Monocular or Binocular, but not true stereo Stereo Binocular
Viewable Objects Slides Coins, stamps, bugs, plants, circuit boards, etc.
Extra Features (depends on model) Mechanical Stage, Coarse & Fine Focus, Bottom light
    *Some models of Inspection Microscope have a continuous zoom from 10x to 30 or 40x

This chart should give you some idea of the basic comparison.

We haven’t forgotten about the third category of microscope: Other. This category covers some odd designs that work as specialty instruments. Some examples of Other microscopes would be:

Hand-Held Microscope: These are small, pocket-sized microscopes used in a fashion similar to Inspection/Dissection microscopes. They may have higher magnification than Inspection microscopes (30-100x power), often have a built in light, and are light and portable. Their main disadvantage is they have a limited viewing field- you must put the scope directly on the object being viewed. Their optics & lighting are also rarely up to the quality of full-sized microscopes, and moving to find a specific part of an object can be tricky. Still they are great in the field where a full-size microscope would be unwieldy.

Digital Microscopes: Many traditional microscopes can have a digital camera built into their structure, or can have their eyepiece replaced with a digital camera. But some microscopes are designed from the ground up to be used as high-power digital microscopes. These items have no eyepiece, only a CCD camera and an objective lens. They may have fixed or variable magnification, and the computer screen resolution will vary from model to model. Many ‘toy’-like designs have VGA quality graphics, which is 480 x 640. This level of quality is acceptable for kid’s use but is not sufficiently detail for any real work or study. Usually 1.3 Megapixels is the highest quality available for devoted consumer digital microscopes. If you desire higher resolution a compound microscope with a digital microscope eyepiece might be in order.

High Power Magnifiers: A hand-held magnifier is a very different instrument from a microscope, seeing as how most magnifiers have about 2-3x magnification and microscopes can go as high as 1000x. But some close work magnifiers have very high power (10x and up) and the line between a microscope and a magnifier starts to get blurred. As far as optical design goes, they are still very different animals: The magnifier has just one lens (or set of cemented lenses) while the microscope has both an objective and eyepiece lens. Although the difference is there, the jobs they cover get blurred. If you need a lower powered microscope or a high power magnifier, make certain you are choosing the correct tool for your viewing needs.

Hybrid Microscopes: Given the difference in use between a compound and an inspection microscope it didn’t take to long for some folks to come up with a design that tries to do the job of both microscopes. Usually this is done by taking a compound microscope design and adding a top-down light to the system. These designs can be a great boon to parents or buyers who cannot decide which usage they would prefer. The disadvantage is that like many other things that try to do multiple jobs, they are not the best at either job. Most often hybrid microscopes are better at being a compound microscope than an inspection microscope (mostly due to the higher powers of a compound microscope), but at least the option for using the microscope both ways is available. Consider a hybrid if you can’t decide between designs, but remember it won’t do the job as well as a devoted microscope.

Toy Microscopes: Many ‘toy’ microscopes are available on the market, usually they are either plastic hand-held models or plastic versions of compound designs. The former can be great fun for small children who would like to have something to view nature close-up but can still handle their not-always-delicate hands. The latter, however, is usually to be avoided. Cheap plastic bodies and cheap plastic lenses will give the viewer a very poor experience indeed. Companies that make these items often pile on junk accessories like plastic ‘viewers’, poor slide making accessories, and other gimmicks to cover the fact that the instrument is junk. Avoid these if at all possible.

OTHER THINGS TO CONSIDER

So now that we’ve discussed the various microscope designs, we should talk about that are features of microscopes:

DIN Objectives: DIN stands for Deutsches Institut für Normung – Don’t worry about that. Just understand that DIN eyepieces are set to a higher standard the the average beginner microscope. DIN objectives are generally universal so you can take one DIN objective out of one microscope and thread it into another. DIN eyepieces are often a bit more costly.

Digital Microscope Eyepieces: Digital eyepieces can be a great boon to your viewing experience. When plugged into a computer they can be used to view objects on a much larger screen, and the images can be saved, modified, emailed, etc. Some digital eyepieces can make movies as well. Some microscopes have digital eyepieces built into the body of the microscope, but almost all non-toy microscopes can have their eyepiece’s removed and replaced with a digital microscope eyepiece. The image quality from a digital microscope eyepiece can go from VGA (or even TV) quality all the way up to 5.0 Megapixels or even more.

ACCESSORIES:

One nice feature about microscopes is that they don’t need a whole lot of accessories to get a good experience. But there are a few things you can get to increase your viewing experience:

Prepared Slides: Professionally made slides are always excellent to have around. They let you see objects with a quality that few can match. They also may be of specimens that may be very hard to obtain. Consider having a few prepared slides to enjoy.

Slide Making Kits: Sooner or later you will want to make your own slides. This will involve blank slides, coverslips, a razor (for cutting samples) and some mounting medium. These can be bought individually, but it is often more economical and convenient to buy a kit.

Special Slides: Blank slides with concave dips can be obtained for holding liquid samples. This is excellent for examining microscopic life in pond water and other sources.

Slide Boxes: Once you make your own slides you should store them properly in a slide box. Don’t leave them to get dust and scratches.

Microtome: If you make a lot of slides, cutting thin sample sections with a razor can get annoying after a while. A microtome can help. It is a mechanical device that helps cut a thin sliver off the sample. Think of them as working like the meat slicer at your deli only on a much smaller scale. Microtomes can be hand driven devices for around $75 to fancy automated item costing hundreds or even thousands of dollars.

CONCLUSIONS:

As mentioned above, before you decide on what model microscope you want, make sure you know what it is you want to do with it! Fun can be had viewing both prepared slides and making your own slides using a compound microscope. But it can also be a real thrill to take objects straight from the backyard, or even from your pockets and put them under an Inspection/Dissection microscope. If you have needs beyond having fun observing (research, coin collecting, etc), make certain that your microscope does that sort of job first and foremost.

Happy viewing!

At last, a Universal Smartphone Microscope Part 1

The fact that nearly everyone is carrying a Smartphone, and therefore a digital camera in their pockets lends itself to some wonderful solutions with just a bit of accesorizing. Lab equipment is being designed around the Smartphone and you can expect more such items in the future.

Now it stands to reason that the camera on your smartphone could be adapted to other optical systems to turn your Smartphone into a telescope or microscope camera.  Well, for telescoping the best that can be done so far is to develop ways to attach the phone to binoculars or telescopes, as they tend to require some hefty optics. But small microscopes are nothing new, so why not attach a microscope system to a Smartphone? Well this was also done, but previous designs did have some issues -namely that to hold the camera you needed to put the smartphone into a special case:

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Testing out the Carson HookUpz IS-100 Universal Smartphone Optics Adapter

Carson Optics has introduced a new product to the world of Smartphones. The HookUpz Universal Smartphone Optics adapter. This is a device that hopes to make the now nearly ubiquitous Smartphones even more useful to hobby and industry as it is supposed to allow you to attach almost any Smartphone to almost any optical system (microscope, binocular, telescope).

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But that brings the question: Does it work? We’ll we spent some time fiddling with one to find out!

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The 5 signs of a bad Microscope

As an extension of our ‘6 Signs of a Bad Telescope’ its time to cover those instruments that see the very, very small.  Not all microscopes are created equal so its time to cover some of those indicators that the microscope you are looking at may not be the best one available!

1) Large Magnifications listed on the box

Unlike the telescopes, this one is a bit more subtle as many low cost microscopes can go up to 400x magnification without issue. Badmicrscope1 But above 400x the image simply is not going to be clear on a cheap microscope. If it advertises itself as have powers above 400x that model had better be professional grade! A typical bad microscope magnification listing seems to be 900x for some reason.

Fact is: When you are using that much power on a microscope you also need to be using something called immersion oil – which is an oil you put between the slide and the lens. This is needed because the change in index of refraction (which is how much the light gets bent as it travels through something) between glass slide, air and then glass lens is too much.

So don’t be fooled by lies on the box.

2) Mirrors.

Badmicrscope2OK, microscopes that use mirrors can be retro for an experienced user who wants the old-school experience, but for budding young biologists mirrors can be very tricky to use. Especially the mirrors on a cheap microscope. They will cause endless amounts of frustration for a young user and adults won’t be very happy about it either.

In this era of microscope construction there is no excuse for having models without a light. LEDs are low cost, low power, and long-lived. Any beginners microscope should have one.

This is not to say that any cheap microscope with a light is automatically home-free. There are plenty of microscopes with poor lighting as well.

3) Optical Projection Screens

This one is actually being reduced in usage so it is very hard to find an example to show you, but we can show badmicroscope3you a digital screen microscope, which is actually a good version of what we are discussing.

Digital images can be lots of fun, sadly a lot of cheap microscopes may use an old optical projection technique that frankly….stinks. It can be done right and projection microscopes are fun to build as a science project (note: link is a .pdf) but for low-cost microscopes the best you can hope for is a murky, distorted image.

4) That tacky, plastic, angled body!

badmicroscope4Ugh. Just ugh!  Cheap molded bodies with casting lines still visible, silvery colored plastic pretending to be metal, or worse. Microscope like this have issues that may not occur to most people: They lack the weight to hold still when being adjusted, they are based off old mirror designs (which does nobody any favors), they can actually melt a little the heat (especially with the dirt cheap models).

This is not to say that all plastic-bodied microscopes are bad. In fact some models have to be made out of plastic due to conductivity issues, but this is usually a tougher plastic.

Cheap plastic models simply have too many issues for long term use: the focuser strips easily, the bodies warp over time, plastic does age well. Plastic bodies also tend to mean plastic lenses, which are a problem of their own.

5) Too many cheap accessories

If you give someone a beginners microscope, it is reasonable to expect there might be a small start kit of accessories that comes with it. This is a good idea so that new students can use their microscope right away. A good starting kit might have the following: some premade slides, a few blank slides, cover slips, tweezers, slide stain, and perhaps a specimen jar. The things you don’t need with a start scope would be: color filters, dissection tools (usually dull and dangerous), and other nonsensical items. Many of these models are sold in packs like you see in the first picture of this entry which is trying to impress you with all the ‘stuff’ it comes with. Don’t get fooled.

Its not very hard to separate the wheat from the chaff with microscopes – certainly it is easier that with telescopes. Just remember that bargain microscopes may not be a real bargain.

Want to buy beginner Microscopes?

www.spectrum-scientifics.com

 

Whodunnit Duo-Scope Microscope

The My First lab Duo-Scope has been a staple in our microscope offerings for ages, and recently My First Labs have added an upgraded version that centers around the world of Forensics. Its the Whodunnit Duo-Scope.

4837 Using the same body and optics as the original Duo-Scope the Whodunnit takes things a step further by adding LED based Ultraviolet lighting to both the top-down and bottom-up. This allows samples viewed in either the inspection mode or the compound mode to be seen under UV lighting. In forensics, many compounds are used that react with crime scene elements so they glow under UV light. Kids using the Whodunnit microscope can see this in action.

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10 Fun Facts About Microscopes!

1) Unlike telescopes, who people incorrectly credit to Galileo, nobody is really certain who invented the microscope. But it wasn’t very long after the telescope was IncanMicroscopeinvented that the first microscope was developed in Northern Europe, doubtless by lens grinders.

2) In the past, the biggest problem with using a microscope was illuminating the subject. Many microscopes used mirrors and they had to be angled just right between a light source and the staging plate. Until recently most kid’s microscopes used mirrors and could be frustrating to use.

3) There are actually two types of microscopes with very different purposes: Biological or Compound microscopes, which many are familiar with, are used for viewing slides. Inspection/Dissection microscopes are used to view specimens directly. Since Inspection Microscopes use two objectives and two eyepieces they give true stereo vision. Compound microscopes do not give stereo vision, even if they have two eyepieces, but most objects on slides are flat anyway. Compounds also give much higher magnification.

4) Most Compound microscopes give magnifications of 40x, 100x, and 400x. Some cheap microscope may promise much higher magnifications but these should not be trusted. Why? because:

5) When you get to magnifications of 600x or more you very likely need to use something called ‘immersion oil’ to effectively view the subject. This is because the lenses at this magnification are very small and tight so just the air between the slide and the glass lens can mess up the path the light takes and distort the image.  Immersion oil reduces that optical aberration.

26796) Many microscopes use what are called “DIN” objectives. This is often seen as a sign of quality and that is usually true, but the DIN usually just means that a lens can be taken from one microscope and put onto another. The DIN is simply noting that the threads for installing the objective lens are the same size & threading.  DIN lenses themselves can be of many optical designs.

7) Once you get past a certain quality level, microscopes tend to become specialized for specific purposes. MOHS microscopes are used in Dermatology, for example.

8) If you see a microscope that has an angled body it is probably based off an old mirror- design and should probably be avoided. Someone is re-using old molds to make an obsolete design. Although these often have lights attached it still makes a poor design for everyday use.

9) When setting up your own microscope be sure to make certain you will be comfortable while using it. Many people have given themselves sore necks by having the microscope set too low. Also, if you have a microscope that is not binocular make sure that when you close one eye you are not making the other one (the one you are viewing with) squint. If you have trouble with this simply cover the other eye with your hand or learn to ignore what that eye is seeing when using the microscope.

10) If you are getting a microscope for yourself or as a gift, be sure to get some things besides a few prepared slides. Blank slides can be used to make your own slides, 2811Concave slides can be used to view living creatures in water (get some from your local pond!).  Slide preparation kits can be used to help prepare and stain slides. Microtomes can be used to cut sliver-thin samples from specimens.  be sure to consider these things for the maximum enjoyment of the microscope!

Want to buy microscopes?

Want to buy microscope accessories?

www.spectrum-scientifics.com

How Lights Your Microscope? A guide to Microscope Lighting.

Ah microscopes. In days past getting enough illumination to see with them was a complex process involving a parabolic mirror, a light source such as a candle (for the old days) and lots of patience. In the 20th century microscopes with lights were developed, but such luxury! They were often expensive and prone to burning through expensive bulbs.

These days we are much luckier with our microscope choices. Almost every microscope in production has some kind of built-in illumination and the handful that don’t are used simply to demonstrate how microscopes without built-in lights work.

But there are sometimes many choices as to how to illuminate your microscope. We are going to cover a few of them and discuss their advantages and disadvantages. Let’s start at the bottom of the heap with:

Mirror Illuminated Microscopes:

MirrorMicroscopeA mirror illumination involves a small parabolic mirror that uses an outside light source (usually a light bulb on the ceiling or a desk lamp) to concentrate light  up through the condenser lens and through the sample material. This is not easy as you must align the microscope with the light source and then angle the mirror just right to get the light to go through the condenser lens. This can get very frustrating, especially for young users.

Advantages:

  • OLD SCHOOL!
  • No batteries or power required.

Disadvantages:

  • Very hard to use
  • Requires outside light source
  • Difficult to control light intensity

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