However, if we look into the smaller worlds that make up the tiny things that can be held in our hand, we can soon find out that changes in order of magnitude in the “tiny things” can be just as dramatic as they are in our understanding of the universe.

With advanced microscopes, and through the study of atomic particles we have learned that smaller, and smaller particles make up the familiar objects we live with from day to day. As we look deeper into that single plant cell, we find structures inside the cell that help it live, and within those structures we find large protein molecules, and within those protein molecules we find individual atoms, and within the atoms we find the basic atomic particles, protons, electrons, and neutrons. Atomic physicists have also discovered tinier, sub-atomic particles like quarks, and mesons, and others. It seems that every time we develop a technology that allows us to see something on a smaller level, we discover that it’s made up of even smaller building blocks. It seems like we are “living in the middle of infinity”.

It’s only through the use of instruments like magnifying glasses, optical telescopes, radio telescopes, microscopes, electron microscopes and various other devices that we’ve come to understand our universe as well as we do now.

So, what is a microscope?

A microscope (from the Greek: μικρός, mikrós, “small” and σκοπεῖν, skopeîn, “to look” or “see”) is an instrument to see objects too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy. Microscopic means invisible to the eye unless aided by a microscope.

An early microscope was made in 1590 in Middelburg, Netherlands. Two eyeglass makers are variously given credit: Hans Lippershey (who developed an early telescope) and Hans Janssen. Giovanni Faber coined the name for Galileo Galilei’s compound microscope in 1625. (Galileo had called it the “occhiolino” or “little eye”.)

The first detailed account of the interior construction of living tissue based on the use of a microscope did not appear until 1644, in Giambattista Odierna’s L’ochio della mosca, or The Fly’s Eye.

It was not until the 1660s and 1670s that the microscope was used seriously in Italy, Holland and England. Marcelo Malpighi in Italy began the analysis of biological structures beginning with the lungs. Robert Hooke’s Micrographia had a huge impact, largely because of its impressive illustrations. The greatest contribution came from Antoni van Leeuwenhoek who discovered red blood cells and spermatozoa. On 9 October 1676, Leeuwenhoek reported the discovery of micro-organisms.

The most common type of microscope—and the first invented—is the optical microscope. This is an optical instrument containing one or more lenses producing an enlarged image of an object placed in the focal plane of the lenses.

There are several types of microscopes.

An electron microscope is a type of microscope that produces an electronically-magnified image of a specimen for detailed observation. The electron microscope (EM) uses a particle beam of electrons to illuminate the specimen and create a magnified image of it. The microscope has a greater resolving power (magnification) than a light-powered optical microscope, because it uses electrons that have wavelengths about 100,000 times shorter than visible light (photons), and can achieve magnifications of up to 1,000,000x, whereas light microscopes are limited to 1000x magnification.

The electron microscope uses electrostatic and electromagnetic “lenses” to control the electron beam and focus it to form an image. These lens are analogous to, but different from the glass lenses of an optical microscope that form a magnified image by focusing light on or through the specimen.

Electron microscopes are used to observe a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, metals, and crystals. Industrially, the electron microscope is primarily used for quality control and failure analysis in semiconductor device fabrication.

Electron microscope constructed by Ernst Ruska in 1933.

In 1931, the German physicist Ernst Ruska and German electrical engineer Max Knoll constructed the prototype electron microscope, capable of four-hundred-power magnification; the apparatus was a practical application of the principles of electron microscopy. Two years later, in 1933, Ruska built an electron microscope that exceeded the resolution attainable with an optical (lens) microscope. Moreover, Reinhold Rudenberg, the scientific director of Siemens-Schuckertwerke, obtained the patent for the electron microscope in May of 1931. Family illness compelled the electrical engineer to devise an electrostatic microscope, because he wanted to make visible the poliomyelitis virus.

In 1937, the Siemens company financed the development work of Ernst Ruska and Bodo von Borries, and employed Helmut Ruska (Ernst’s brother) to develop applications for the microscope, especially with biologic specimens. Also in 1937, Manfred von Ardenne pioneered the scanning electron microscope. The first practical electron microscope was constructed in 1938, at the University of Toronto, by Eli Franklin Burton and students Cecil Hall, James Hillier, and Albert Prebus; and Siemens produced the first commercial Transmission Electron Microscope (TEM) in 1939. Although contemporary electron microscopes are capable of two million-power magnification, as scientific instruments, they remain based upon Ruska’s prototype.

Transmission electron microscope (TEM)

The original form of electron microscope, the transmission electron microscope (TEM) uses a high voltage electron beam to create an image. The electrons are emitted by an electron gun, commonly fitted with a tungsten filament cathode as the electron source. The electron beam is accelerated by an anode typically at +100 keV (40 to 400 keV) with respect to the cathode, focused by electrostatic and electromagnetic lenses, and transmitted through the specimen that is in part transparent to electrons and in part scatters them out of the beam. When it emerges from the specimen, the electron beam carries information about the structure of the specimen that is magnified by the objective lens system of the microscope. The spatial variation in this information (the “image”) is viewed by projecting the magnified electron image onto a fluorescent viewing screen coated with a phosphor or scintillator material such as zinc sulfide.

The image can be photographically recorded by exposing a photographic film or plate directly to the electron beam, or a high-resolution phosphor may be coupled by means of a lens optical system or a fibre optic light-guide to the sensor of a CCD (charge-coupled device) camera. The image detected by the CCD may be displayed on a monitor or computer.

Resolution of the TEM is limited primarily by spherical aberration, but a new generation of aberration correctors have been able to partially overcome spherical aberration to increase resolution. Hardware correction of spherical aberration for the High Resolution TEM (HRTEM) has allowed the production of images with resolution below 0.5 Ångström (50 picometres) at magnifications above 50 million times. The ability to determine the positions of atoms within materials has made the HRTEM an important tool for nano-technologies research and development.

Scanning electron microscope (SEM)

Unlike the TEM, where electrons of the high voltage beam carry the image of the specimen, the electron beam of the Scanning Electron Microscope (SEM)[8] does not at any time carry a complete image of the specimen. The SEM produces images by probing the specimen with a focused electron beam that is scanned across a rectangular area of the specimen (raster scanning). At each point on the specimen the incident electron beam loses some energy, and that lost energy is converted into other forms, such as heat, emission of low-energy secondary electrons, light emission (cathodoluminescence) or x-ray emission. The display of the SEM maps the varying intensity of any of these signals into the image in a position corresponding to the position of the beam on the specimen when the signal was generated. In the SEM image of an ant shown at right, the image was constructed from signals produced by a secondary electron detector, the normal or conventional imaging mode in most SEMs.

Generally, the image resolution of an SEM is about an order of magnitude poorer than that of a TEM. However, because the SEM image relies on surface processes rather than transmission, it is able to image bulk samples up to many centimetres in size and (depending on instrument design and settings) has a great depth of field, and so can produce images that are good representations of the three-dimensional shape of the sample.

Reflection electron microscope (REM)

In the Reflection Electron Microscope (REM) as in the TEM, an electron beam is incident on a surface, but instead of using the transmission (TEM) or secondary electrons (SEM), the reflected beam of elastically scattered electrons is detected. This technique is typically coupled with Reflection High Energy Electron Diffraction (RHEED) and Reflection high-energy loss spectrum (RHELS). Another variation is Spin-Polarized Low-Energy Electron Microscopy (SPLEEM), which is used for looking at the microstructure of magnetic domains.

Scanning transmission electron microscope (STEM)

The STEM rasters a focused incident probe across a specimen that (as with the TEM) has been thinned to facilitate detection of electrons scattered through the specimen. The high resolution of the TEM is thus possible in STEM. The focusing action (and aberrations) occur before the electrons hit the specimen in the STEM, but afterward in the TEM. The STEMs use of SEM-like beam rastering simplifies annular dark-field imaging, and other analytical techniques, but also means that image data is acquired in serial rather than in parallel fashion.

Low voltage electron microscope (LVEM)

The low voltage electron microscope (LVEM) is a combination of SEM, TEM and STEM in one instrument, which operates at relatively low electron accelerating voltage of 5 kV. Low voltage increases image contrast which is especially important for biological specimens. This increase in contrast significantly reduces, or even eliminates the need to stain. Sectioned samples generally need to be thinner than they would be for conventional TEM (20-65nm). Resolutions of a few nm are possible in TEM, SEM and STEM modes.

How to choose the best microscope.

Before discussing the specific varieties of microscopes on the market, there are two important features to become familiar with before going shopping—a microscope’s light source and magnification range.

Microscope Light Source: “Bargain” scopes will often have a mirror, or very small bulb, as a light source. Light is necessary for observing a specimen with a microscope. The amount of light determines the level of contrast between the object and the background. Too little light and you can’t see the specimen. Too much light and the specimen becomes washed out, and equally difficult to see. My recommendation is to stay away from cheap microscopes that use mirrors to illuminate objects. It is difficult to get sufficient light for a good image.

Microscope Magnification: Dissecting, or stereo, microscopes are designed to magnify objects that can already be seen with the naked eye, allowing the observer to discern additional detail. These are low magnification scopes with a range of approximately 10x to 40x actual size (with “x” meaning times). Microscopes with the ability to provide low levels of magnification are great for little kids who want to get a better look at things that they encounter in the world around them, such bugs, leave, flowers and other small objects.

Compound microscopes provide two sets of lenses, that together deliver high magnification, generally from 40x to 1000x, depending on the specific lenses that they come with. These high magnification scopes are great for seeing items that are not visible to the naked eye, and allow users to see essentially invisible things, such as bacteria, the details of pollen grains—tiny stuff. And high magnification scopes provide more great details.

An early microscope was made in 1590 in Middelburg, Netherlands. Two eyeglass makers are variously given credit: Hans Lippershey (who developed an early telescope) and Hans Janssen. Giovanni Faber coined the name for Galileo Galilei’s compound microscope in 1625. (Galileo had called it the “occhiolino” or “little eye”.)

The first detailed account of the interior construction of living tissue based on the use of a microscope did not appear until 1644, in Giambattista Odierna’s L’ochio della mosca, or The Fly’s Eye.

It was not until the 1660s and 1670s that the microscope was used seriously in Italy, Holland and England. Marcelo Malpighi in Italy began the analysis of biological structures beginning with the lungs. Robert Hooke’s Micrographia had a huge impact, largely because of its impressive illustrations. The greatest contribution came from Antoni van Leeuwenhoek who discovered red blood cells and spermatozoa. On 9 October 1676, Leeuwenhoek reported the discovery of micro-organisms.

The most common type of microscope—and the first invented—is the optical microscope. This is an optical instrument containing one or more lenses producing an enlarged image of an object placed in the focal plane of the lenses.

“Microscopes” can be separated into optical theory microscopes (Light microscope), electron microscopes (e.g., TEM), and scanning probe microscopes (SPM). Optical microscopes function through the optical theory of lenses in order to magnify the image generated by the passage of a wave through the sample, or reflected by the sample. The waves used are electromagnetic (in optical microscopes) or electron beams (in electron microscopes). Types are the compound light, stereo, and the electronic microscope. There is also professional microscope and we would like to tell you more about it here.

Professional Microscope has been highly approved by all who have used it, as it combines many advantages not heretofore found in any but the highest priced instruments.

The Professional Microscope stands fifteen inches high when inclined as shown in the engraving the base is of brass, with uprights to receive the axis, upon which the body inclines to any convenient angle. The body is of brass, finely finished with extension draw-tube.

The coarse adjustment for focus is by a delicate watch chain, controlled by a large milled head on each side of the tube; far more efficient and precise than the majority of Rack movements, and will readily adjust the focus for all except the very highest magnifying powers. The fine adjustment for focus is by a very delicate Micrometer Screw acting directly upon the body of the instrument, and moving the entire optical system vertically; free from the irregular lateral movement so often inseparable from an adjustment acting only on the Objective.

The Stage is large and steady, but at the same time thin, allowing facility for extreme obliquity of illumination. To the upper surface a Plate Glass Stage is attached, which can be freely moved in a vertical or horizontal direction to any desirable extent, and can also be revolved. The motion of this Plate Glass Stage is so delicate and simple, that many experienced microscopists prefer it to the elaborate screw stage. A movement as minute as 1-12000 inch can be selected by it. A brass rest with springs to hold the object, is clamped to it, but can be removed in a moment, leaving a clean glass plate for examination of recent anatomical preparations, chemicals, or other substances which would injure the usual Brass Stage. Beneath the Stage is a separable collar carrying the Diaphragm, and also adapted to receive the Polarizer, Parabolic Illuminator, and other accessories.

The Concave and Plain Mirrors are mounted with universal motion, and slide on a jointed bar for direct or oblique illumination.

The mounting for the Objectives is made with the ” London Society Screw,” so that the Objectives of all first-class makers, can be used with the instrument.

Wouldn’t it be exciting to watch your son or daughter pick up a small stone from the ground, bring it home, and look at it through the microscope. Your child will be able to determine if a rock is primarily quartz or possibly a sedimentary rock like sand stone. This will lead to further questions about the formation of this rock and a search for other rocks.

Just imagine walking with your child and finding a feather from a bird.  With the microscope you can now discover a feather up close. You might think that a feather isn’t that complex, but when you put it under a microscope you will notice that it is made up of many components. You may see that a feather looks like a tree with the Rachis as the trunk and the Barb and Barbules look like branches and leaves. The feather will amaze you as you discover something so simple and complex as a feather.

You can discover even more secrets of the world. The microscopes are great for kids because it helps them discover the tiny wonders of the world around them. From insects and rocks to pond and creek water this is a great buy for the little ones in your life.  It’s a great gift for your child no matter what time of year.

You can observe bugs and rocks, but you can also look at salt, spices, hair and you can even see every colored strand in different types of fabrics. Your kids will become even more curious with the little things that make up the big world around them.

Microscopes are great educational toys that allow your children to explore the world while having fun developing their science skills. But there are several types with varying levels of quality and cost, each suited to a different need.

Here’s how to find the best microscope for your family.

Microscope Features to Consider

Before discussing the specific varieties of microscopes on the market, there are two important features to become familiar with before going shopping—a microscope’s light source and magnification range.

Microscope Light Source: “Bargain” scopes will often have a mirror, or very small bulb, as a light source. Light is necessary for observing a specimen with a microscope. The amount of light determines the level of contrast between the object and the background. Too little light and you can’t see the specimen. Too much light and the specimen becomes washed out, and equally difficult to see. My recommendation is to stay away from cheap microscopes that use mirrors to illuminate objects. It is difficult to get sufficient light for a good image.

Microscope Magnification: Dissecting, or stereo, microscopes are designed to magnify objects that can already be seen with the naked eye, allowing the observer to discern additional detail. These are low magnification scopes with a range of approximately 10x to 40x actual size (with “x” meaning times). Microscopes with the ability to provide low levels of magnification are great for little kids who want to get a better look at things that they encounter in the world around them, such bugs, leave, flowers and other small objects.

Compound microscopes provide two sets of lenses, that together deliver high magnification, generally from 40x to 1000x, depending on the specific lenses that they come with. These high magnification scopes are great for seeing items that are not visible to the naked eye, and allow users to see essentially invisible things, such as bacteria, the details of pollen grains—tiny stuff.

High magnification scopes are more difficult for small children to use, and have the limitation of over-magnifying objects that can be seen with the naked eye. They provide great detail, but the detail may be so minute that young children can’t really relate to what they are seeing.

Types of Microscopes:

There are essentially three main types of microscopes to select from when buying a student scope: Computer Microscopes, Dissecting Microscopes and Compound Microscopes. Here us a breakdown of the advantages and disadvantages of each.

Computer Microscopes: In an age of technology, the computer, or digital, microscope is usually the best value, and most flexible option. These scopes allow specimens to be viewed on a computer screen, and generally have a wide range of magnifications from low (10x) to quite high (200x). The image of the specimen can be saved as a graphic file, as well as manipulated and printed, which is handy for science projects. There are many cheap digital scopes out there, for less than $100, and, if you are purchasing the microscope as merely a cool toy for the kids, a less expensive scope will do a decent job. To get a good quality computer microscope that produces higher resolution images, plan to spend at least $150.00.

Compound Microscopes: As mentioned above, compound scopes provide high levels of magnification, and are great for looking at tiny objects, but are a bit more challenging to operate—a good choice for junior high and high school students. There are compound microscopes that have computer adapters, but they can be costly. The price of a good quality, basic student grade compound microscope starts at approximately $120.00.

Stereo Scopes: With a typical magnification range of 10x – 40x, stereo microscopes work well for examining larger items, and since the magnification is lower, focusing is a less exacting task. Still plan to spend at least $75.00 and for a good student grade scope, and, as with all three types of microscopes, the prices vary widely according to quality.

History
In the 1600s, Robert Hooke (now known as the father of microscopy) discovered that living things were composed of cells while looking at a piece of cork under his primitive microscope. Since that time, microscopes have become increasingly sophisticated and capable of seeing even smaller things. They are now indispensable instruments in many areas of health care.

Significance
Many disease-causing organisms are microscopic. Hospitals routinely take samples from patients in an attempt to identify these microscopic organisms, which allows them to prescribe the appropriate medication. Bacterial cells are identified by shape, size and configuration. They are also identified using different staining techniques (such as Gram’s staining). Each of these methods of identification requires the use of a microscope.

Identification
Cells within body tissues all have characteristic shapes, sizes and configurations. Within hospitals, doctors can take samples of cells to determine whether the cells are functioning properly. Biopsies are small pieces of tissue from any part of the body that are taken for the purpose of examining them microscopically. These tissues are fixed, sliced and mounted on slides before being viewed by a pathologist to determine whether diseases such as cancer are present. Blood counts can also be performed microscopically. The number of red blood cells can indicate anemia or an individual’s level of fitness. If white blood cells are elevated, it can indicate infection. Furthermore, there are several classes of white blood cells, and elevation of any one type can indicate a specific type of affliction. For instance, a high number of basophils can indicate an allergic reaction. Sperm counts can be performed microscopically in the manner similar to blood cell counting.

Types
There are several types of microscopes that can be used by a hospital. Compound light microscopes are the most common type. The images are two dimensional, and are magnifed through a series of lenses and illuminated from a light source.

The ‘Light’ Part of a Microscope
A light microscope uses a beam of visible light to illuminate and contrast the object being viewed through the scope. The light source is typically an incandescent bulb which is turned on by a toggle switch at the side of the base. The beam of light shines up from a lamp in the microscope’s base, through a hole or ‘window’ in the stage (area of the scope where the specimen sits), ultimately up through the specimen.
Contrast results when the area surrounding the object is bright, from the light, and the object being viewed is darker in comparison. It is important to be able to control the level of contrast when using a light microscope, since too much light can make it difficult to see a somewhat transparent or light-colored object (this is called ‘burn out’ in scope speak). Illumination can usually be controlled two different ways:
By adjusting the iris diaphragm, just under the stage: This lever controls the amount of light that enters the condenser which will allow for appropriate contrast. In general, close the diaphragm on low power, (allowing for reduced amounts of light to reach the stage) and open the diaphragm to let more light through at the higher power objectives.
By adjusting a dial on the side of the base: This dial turns the light source up and down, making it brighter or dimmer.

The ‘Compound’ Part of a Microscope
The magnification of a compound microscope is the result of two lenses:
1.    the ocular lens or lenses
2.    the objective lenses
The ocular lens is the one closest to the eye, and usually magnifies objects ten times (10X) their actual size. The objectives are a collection of lenses located on the rotary nosepiece. There are usually three or four objective lenses, each allowing for different degrees of magnification:

•    Scanning power objective: The shortest objective. This lens usually has a red stripe around it, and magnifies objects four times actual size (4X).
•    Low power objective: The next shortest objective. This lens usually has a yellow stripe around it, and magnifies objects ten times their actual size (10X).
•    High-dry objective: This is usually either the longest, or second longest objective. This lens typically has a blue stripe around it, and magnifies objects forty times their actual size (40 X).
•    Oil immersion objective: If a compound scope has this lens, it is the longest, and typically has a black or both a black and white stripe around it. The oil immersion lens magnifies objects one hundred times (100X), and must be used with a drop of oil placed directly on the specimen and fills the space between the lens and specimen.

The total magnification is determined by multiplying the power of the objective by the power of the ocular. (For example, the total magnification at scanning power is 4X times 10X = 40X). Using these two sources of magnification is what makes a microscope compound.

Another type of microscopes that can be used by a hospital is an electron microscope. Electron microscopes are also available, but are very costly to own and operate. An electron microscope is a type of microscope that produces an electronically-magnified image of a specimen for detailed observation. The electron microscope (EM) uses a particle beam of electrons to illuminate the specimen and create a magnified image of it. The microscope has a greater resolving power (magnification) than a light-powered optical microscope, because it uses electrons that have wavelengths about 100,000 times shorter than visible light (photons), and can achieve magnifications of up to 1,000,000x, whereas light microscopes are limited to 1000x magnification.
The electron microscope uses electrostatic and electromagnetic “lenses” to control the electron beam and focus it to form an image. These lens are analogous to, but different from the glass lenses of an optical microscope that form a magnified image by focusing light on or through the specimen.
Electron microscopes are used to observe a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, metals, and crystals. Industrially, the electron microscope is primarily used for quality control and failure analysis in semiconductor device fabrication.

Insects are part of our everyday life. Most of the insects are specialist. They are well adapted in a particular role they take part in life. A study of insects adaptations and specializations offers fascinating insight into the amazing varied population on Earth.

Spiders, crickets, even cockroaches are important. Using microscope, you will be able to find out what is inside an insect, how their body parts functions, and how they look without doing exactly the experiment. You will be able to explore the world of insects. Explore the world of insects, and be able to meet each of them in nature!

Many insects are aquatic or have their home in the water. So, expect that in a certain body of water you can find larvae of insects. These aquatic insects are not normally microscopic but when you examine with the microscope you can find many interesting features. Aquatic insects are mostly transparent and when you look closely at them you can identify and see its anatomical features. It will be better if you will have a power microscope for this study.

There are four main types of microscopes that a biologist uses: dissection, compound, Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM).

There is certain terminology used when discussing microscopes. Magnification is referring to the ratio of the size seen in the microscope to the actual size of the specimen. On a compound microscope it is usually between 4x and 100x. Resolution is the clarity and detail seen. It is the minimal distance between two points in which they can be seen separately (i.e.: not blurred). Field of view refers to how much you actually see when looking in a microscope. As field of view increases, magnification decreases. Depth of field is the number of layers you see. Total magnification is the product of the objective lens and the ocular (10x). Parfocal is a term used when describing compound microscopes. this means that the focus is maintained when changing the magnification. This way you don’t have to re-focus when changing powers.

A dissection microscope is light illuminated. The image that appears is three dimensional. It is used for dissection to get a better look at the larger specimen. You cannot see individual cells because it has a low magnification.

A compound microscope is also light illuminated. The image seen with this type of microscope is two dimensional. This microscope is the most commonly used. You can view individual cells, even living ones. It has high magnification (from 4x – 100x). However, it has a low resolution.

SEM use electron illumination. The image is seen in three dimension. It has high magnification and high resolution. The specimen is coated in gold and the electrons bounce off to give you and exterior view of the specimen. The pictures are in black and white.

TEM is also electron illuminated. This gives a two dimensional view. Thin slices of specimen are obtained. The electron beams pass through this. It has high magnification and high resolution.

A compound microscope contains twelve basic parts. The ocular is the eye piece. It is what you view through. It contains a lens of with a magnification of 10x. The ocular is attached to the body. The body, also called the barrel, contains a mirror to view the image at an angel. The arm of the microscope is used as a handle when moving microscopes. It extends from the body to the base. The nosepiece holds the objective lens and is attached to the body. The objective lens magnifies by the power. The mechanical state is where the slide goes. It can be adjusted accordingly. The diaphragm controls the amount of light. The condenser focuses the light on the image. The light source is whit light used to illuminate the specimen. The coarse adjustment focuses on low powers while the fine adjustment is used to focus on high lenses. The base holds the light source.

To operate a microscope properly, you should follow some simple steps. First you must plug it in and turn it on. Make sure it is set on the lowest power. Move the stage to the top position.

Place the slide on the stage agist the corner. Adjust the stage. Use the coarse adjustment to get the image in focus. Use the fine adjustment to see more detail. Finally move the lens clockwise to move to higher magnification. Your specimen should be seen clearly in focus even when changing powers.

Good luck in your insects studies!

DOF  A little technical this week, but once you have mastered the technique, DOF is totally under your control. What is DOF? Quite simply, it is Depth Of Field, and mastery of DOF really is the second rule of photography in my opinion. The first rule is to walk several meters closer to the subject!

Taken at f4
The term DOF refers to an optical one and depends solely on the lens being used and the aperture selected. Altering the shutter speed, does not change the Depth of Field in any way at all.
Depth of Field really refers to the zone of “sharpness” (or being in acceptable focus) from foreground items to background items in any photograph. This is different from what the eye sees, as the eye can instantly focus on near and far objects, giving the impression that everything in your field of vision is in sharp focus. The camera, however, gives you a slice of the distance.
The first concept to remember is “1/3rd forwards and 2/3rds back.” Again this is a law of optical physics, but means that the DOF, from foreground to background in your photograph can be measured, and from the sharpest focus point in the photo, extends towards you by one third and extends away backwards from the focus point by two thirds.

Taken at f16
For those of you with SLR’s, especially the older manual focus SLR’s, you will even find a series of marks on the focussing ring of the lens to indicate the Depth of Field that is possible with that lens.
You see, for each focal length of lens, the DOF possible is altered by the Aperture. The rule here is simple – the higher the Aperture number, the greater the DOF and the lower the Aperture number, the shorter the DOF. In simple terms, for any given lens, you get greater front to back sharpness with f22 and you get very short front to back sharpness at f4.
For example, using a 24 mm focal length lens focussed on an object 2 meters away – if you select f22, the DOF runs from just over 0.5 meter to 5 meters (4.5 meters total), but if you select f11 it only runs from 1 m to 4 m (3 m total) and if you choose f5.6 the Depth of Field is only from 1.5 m to 3 m (1.5 m total).
On the other hand, using a longer 135 mm focal length lens focussed at the same point 2 meters away, you get the following Depths of Field – at f22 it runs from 1.9 m to 2.2 m (0.3 m) and at f5.6 it is 1.95 m to 2.1 m (a total of 0.15 m).
Analysis of all these initially confusing numbers gives you now complete mastery of DOF in any of your photographs. Simply put another way – the higher the Aperture number (aim for f22), the greater the DOF; the smaller the Aperture number (aim for f4) the smaller the DOF; plus the longer the lens (135 mm and up), the shorter the DOF, the shorter the lens (35 mm and smaller), the longer the DOF (just remember the ‘opposites’ – the longer gives shorter).
Now to apply this formula – when shooting a landscape for example, where you want great detail from the foreground, right the way through to the mountains five kilometers away, then use a short lens (24 mm is ideal) set at f22 and focussed on a point about 2 km away.
On the other hand, when shooting a portrait where you only want to have the eyes and mouth in sharp focus you would use a longer lens (and here the 135 is ideal) and a smaller Aperture number of around f5.6 to f4 and focus directly on the eyes to give that ultra short Depth of Field required.
Master it this weekend, and just remember that these optical laws hold good for all cameras, be they film or digital.
Take great pictures in 2010.

by Harry Flashman

I believe just about every semi-serious photographer dreams about getting paid for his pictures. And it does happen. Our own coin collector Jan Olav Aamlid went up the Pattaya Park Tower with a bunch of loonies called BASE jumpers who jumped off the parapet and floated to earth via parachute. Jan Olav got some photographs that ended up being published in Norway and he got paid handsomely. Jan Olav, in fact, couldn’t believe just how much!

Photo by Richard Sharabura

When Harry Flashman became a “pro” do you know what his best piece of equipment was? No, it wasn’t his camera. No, it wasn’t the flash lighting gear. No, it wasn’t the tripod or a reflector. It was a book!

That book was written by a Canadian professional photographer, Richard Sharabura, and was called “Shooting your way to a $ Million”. Harry here, carried that book as his personal bible, and still refers to it. Written in 1981, the advice is just as pertinent today as it was twenty-one years ago. Anyone who has ever contemplated any form of “pay me for my pictures” should read this book. By the way, previously when I wrote about this book, local amateur Ernie Kuehnelt went looking and managed to locate a second hand one through Amazon Dot Com, so it is still possible to find copies.

The opening paragraphs state: “No other profession spawns more eager hopefuls. No other profession calls so many and chooses so few.” He goes on “ … Practically every photographer has a preconceived notion about what he (or she) will shoot or not shoot. This is probably one of the most common stumbling blocks to financial success.”

Sharabura believes in being a generalist. In other words, you should be able to shoot anything. And I mean everything. It is no good saying to a potential customer, “Sorry, but I only shoot camels in mid-summer!” You have no idea of the number of photographic jobs that come from one initial request to shoot one particular subject. Harry started with a shot of a concrete truck, which expanded into a glamour calendar, then an engagement shot and a wedding – all from the same corporate executive. Be versatile is the answer!

There is no secret to becoming versatile. Just as the tennis pro’s play lots of tennis to get to the top, so do the photographic pro’s shoot lots of film to get to the top.

A good exercise is to pretend you are now the ace photographer for the Pattaya Mail! Just take a look at the different pictures in any newspaper and see what I mean about being versatile. There are photos of visiting celebrities, holes in the road, funerals, schools, construction sites, sporting tournaments and even babies.

Each weekend give yourself an assignment and go out and cover it pictorially. Here’s a few for you to try: the bus station, shopping on Beach Road, nightlife, the local laundry, life as a petrol pump attendant, beggars, baht busses. The list is as big as your imagination. Just choose one and get ready to shoot it this weekend.

Go out and illustrate your topic, as if the editor had told you to cover it. Make your shots describe the action, scene or activity. Think about how you are going to do it and how you are going to show it. Make the subject the “hero” and the main item of interest in all the shots.

Do all that and you are already thinking like a “pro”. Do it enough times and you will takes shots like a “pro”. Do that enough times and people will pay you like a “pro”.

The same can happen for you – just keep on shooting film and eventually someone will pay you for your hobby! And being paid for something you like doing is a real buzz! But remember that like all things – practice makes perfect!

This series will help you to choose a camera for you and your family. All tips are given by retail store managers with immense knowledge on cameras. So we start with these questions:

“My wife is 20 to 50 years old. She loves photographs, but photography is not her hobby. I should appreciate it if you will write me what camera I should buy as a gift. And why?”

Manager of Gibbs Camera House recommends: “The Canon Powershot S90 would be an excellent choice because of its compact size and functionality. Being a compact camera it’s small enough to take everywhere and record the days events, and when the fancy takes you it also gives the control required to get creative and make that masterpiece for the living room wall!”
Our review of the Canon Powershot S90

“My husband is 20 to 50 years old. He loves photographs, but photography is not his hobby. I should appreciate it if you will write me what camera I should buy as a gift. And why?”

Manager of Gibbs Camera House recommends: “The Olympus MJU-8000 is a popular choice for guys because of it’s robust Chassis and waterproof ability. Being Snow proof, waterproof to 10 meters and crush proof to 100kg it is safe to take along to almost any outdoor event or past time.

Our review of the Olympus MJU-8000

A second choice you might like to consider is the Ricoh CX-1. Having an SLR camera equivalent zoom of 28-200mm this camera sports a 9.1 megapixel high dynamic range sensor which turns even the most difficult of lighting conditions in to photographs you’ll be proud to show off to your mates.”

Our review of the Ricoh CX-1