Understanding Optical Tools and Miscellaneous Optical Tools is our discussion at this time, This is it ...

Is it among your classmates who wear glasses? Have you ever used a microscope or a loop while doing an experiment at the Laboratory? Or have you seen people taking pictures? The tools used in the activity are called optical devices. In this post we will discuss about the optical tools that are around us and will also release the optical tools are qualitatively and quantitatively.

A. Understanding

Optical devices are tools that work on the principle of light. Optical tools make human life easier and more meaningful. You can enjoy the beauty of the universe, capture the most beautiful moments on a photo sheet, or even be able to make a hair on the head to look as big as an arm.

Optics is a branch of physics, which describes the behavior and properties of light, and the interaction / light relation with matter. Examples of optical devices include eye, camera, loop, microscope, and telescope.


Used to see what humans and animals have. The eyes are the only sophisticated optical devices that are not man-made. The shadow properties of the eye are real, reversed, and can be minimized.

Every human being has the most advanced optical tool ever, the eye. The eye is part of the senses that serve to see. Eyes help us enjoy the beauty of nature, see friends, observe the objects around, and much more that we can enjoy through the eyes. Just imagine if humans do not have our eyes or eyes blind, of course the world looks pitch black.

When observed, it turns the eye consists of several parts that each have different functions but support each other. The important parts of the eye are, among others, the cornea, pupils, iris, aquaeus humor, accommodation muscle, eyepiece, retina, vitreous humor, yellow spots, blind spots, and eye nerves.

• The cornea. The cornea is the outer part of the eye that is thin, soft, and transparent. The cornea functions to receive and pass on the incoming light to the eye, and to protect the sensitive eye area beneath it.

• Pupils. The pupil is a narrow gap in the shape of a circle and serves to allow light to enter the eye.

• Iris. Iris is a black, blue, or brown membrane that serves to regulate the size of the pupil. This color is what you see as the color of a person's eyes.

• Aquaeus Humour. Aquaeus humor is a liquid in front of the lens of the eye to refract light into the eye.

• Muscle Accommodation. The muscle of accommodation is the muscle attached to the lens of the eye and serves to regulate the thickness and thinness of the lens of the eye.

• Eye lens. The lens of the eye is convex, fibrous, elastic, and clear. This lens serves to refract the light from the object to form a shadow on the retina.

• Retina. The retina is the back of the eye that serves as a form of shadow.

• Vitreous Humor. Vitreous humor is a fluid inside the eyeball that serves to pass light from the lens to the retina.

• Yellow Spot. Yellow spots are part of the retina that serves as a clear shadow formation.

• Blind Spot. The blind spot is the part of the retina that when the shadow falls on this part, the shadow appears unclear or blurred.

• Eye nerve. The eye's nerve serves to pass the shadow stimulus from the retina to the brain. 

The process of visible objects by the eyes of objects that are in front of the eye reflects light. The light passes into the eye through the pupil which will then be refracted by the lens of the eye to form a shadow on the retina. By nerve, the shadow is passed to the nerve center (brain), so you are impressed to see the object.

A. Daya Accommodation Power

Your eyeball is fixed, so the distance of the eye lens to the retina is also fixed. This means that the distance of the shadow that is formed by the lens of the eye is always fixed, but the distance of the object that we see is different. How can we still see objects with fixed shadow distances, even if the distance seen is changed? Of course we have to change the focal distance of the lens, by changing the lens lens. This is what causes us to see objects that have different distances without difficulty. This ability is a gift of God that until now humans have not been able to imitate it.

Eye lenses can be inflated or automatically flattened because of the accommodation muscles (ciliary muscle). To see objects that are close, the siliar muscle tensing so that the lens of the eyes bulge and vice versa to see the far distance, the ciliary muscles relax (relax), so the lens of the eye flattening. The ability of the eye muscle to thicken or flatten the lens of the eye is called the eye accommodation power.

In order for objects / objects to be seen clearly, the object must lie in the eye sight, ie between the near point and the point of the eye. The near point (punctum proximum = pp) is the closest point that can still be seen clearly by the eye (± 25 cm). At this point near the eye lens will be maximum inflated. The distant point (punctum remotum = pr) is the furthest point still visible to the eye, its distance is infinite. At this distant point, the eyepiece will be flattened maximally.

B. Eyes Disabled

Not all human eyes can form a shadow right on the retina, there is an anomaly eye. This can occur because the accommodation power of the eye has been reduced so that the point of distant or point near the eye has shifted. Such eye condition is called an eye defect.

An eye defect suffered by a person can be caused by excessive eye work (eye habits) or birth defects.

1) Miopi (Long-Weighted)

Miopi is a condition of the eye that can not see clearly objects that are far away. Patients with miopi point closer than infinity (distant point <~) and near point less than 25 cm. This happens because the lens of the eye can not be flattened as it should be so that the image of a distant object will fall in front of the retina. To be able to see distant objects in order to appear clear, patients with miopi helped with glasses concave lens (negative).

Miopi can occur because the eye is too often / used to see objects that are close. This eye defect is often experienced by clocks, welders, computer operators, and so forth.

2) Hipermetropy (Near Rabun)

Hipermetropy is a defect in the eye where the eye can not see clearly objects that are located close. The closer point is further than the point near the normal eye (close point> 25 cm).

Hypertrophic patients can only see clearly objects that are far away so that these eye defects are often called distant light eyes. Hipermetropy is caused by the lens of the eye is too flat and difficult to be inflated so that when you see objects that are located close, the shadow falls behind the retina. In order to be able to see objects that are located close to clear, hipermetropi sufferers are helped by a convex lens (positive).

Hipermetropy can occur because the eye is too often / accustomed to seeing distant objects. This eye defect is often experienced by people who work as a driver, captain, pilot, machinist, and so forth.

3) Presbyter (Old Eye)

People who are old, usually accommodating power has been reduced. In the presbyterian eye, the closer point is farther than the point near the normal eye (close point> 25 cm) and the point closer than the distant point of the normal eye (distant point <~). Therefore, presbyter sufferers can not see objects that are located near or far.

To be able to see far away clearly and to read at normal distances, presbyteris can be assisted by multiple lens glasses (bifocal glasses). Bifocal glasses are glasses consisting of two lenses, the concave lens and convex lens. The concave lens serves to see distant objects and convex lenses to see near / read objects.

4) Astigmatism

Astigmatism is an eye defect in which the curvature of the lining of the membrane or lens is unevenly so that the beam of light that concerns the eye can not be perfectly centered. The astigmatism flaw can not distinguish vertical lines with horizontal stripes together. This eye defect can be helped by cylindrical lens glasses.

C. Eye Trick

Besides having many advantages, the human eye also has some limitations. Therefore, in observation and measurement, the eye does not always give the right things. Look at the following picture!


An optical device consisting of two convex lenses (positive lenses), ie as an objective lens and an ocular lens. This microscope serves to see objects that can not be seen directly with the naked eye, such as bacteria, microbes, viruses, and cells of plants, animals, and humans.

A microscope is a tool used to look at small objects in order to appear clear and large. The microscope consists of two convex lenses. The lens that is close to the observed object (the object) is called the objective lens and the lens close to the observer is called the ocular lens. A microscope that has two lenses is called a dual lens light microscope.

Because the microscope consists of two positive lenses, the objective lens is made stronger than the ocular lens (the focus of the objective lens is shorter than the focus of the ocular lens). This is so that the objects observed look very large and the microscope can be made more practical (shorter).

The object to be observed is placed on a preparatory glass in front of the objective lens and is in objective lens II space (fobj <s <2 fobj). This causes the shadow formed to be real, inverted and enlarged. The shadows formed by the objective lens are objects to the ocular lens.

To get a clear shadow, you can shift the ocular lens by rotating the adjust button. So that the shadow looks bright, under the object is placed a concave mirror that serves to collect light and directed at the object. There are two ways to use a microscope, ie, with maximum accomodated eyes and with unaccommodated eyes.

The shadow properties formed on the microscope are as follows.

• The shadow formed by the objective lens is real, reversed, and enlarged.
• Shadows formed ocular lens is virtual, upright, and enlarged.
• The shadow formed by the microscope is virtual, reversed, and enlarged to the object.


Optical devices that have mechanisms similar to the mechanism of action of the eye. Consists of film, camera lens (convex lens), diaphragm, focus regulator, speed regulator opening and closing the screen. The camera's shadow properties are real, inverted, and scaled down.

A camera is a device used to produce photographic shadows on a negative film. Have you ever used a camera? Usually you use the camera to capture important events.

The camera consists of several parts, among others, as follows:

• Convex lens, serves to refract the incoming light to form a real shadow, reversed, and reduced.

• Diaphragm, is a small, adjustable hole and serves to regulate the amount of light entering through the lens.

• Aperture, serves to regulate the size of the diaphragm.

• Film plates, serves as a shadow spot and produces a negative image, which is a colored image that is not the same as the original, translucent.

In the camera there is a convex lens that serves as a shaper forming. If an object is placed in space three a convex lens will form a real, inverted, and reduced image. Between the camera and the human eye there are similarities, ie objects taken by the camera and objects that the human eye sees in space three and the camera lens or eyepiece. So that shadow is formed which is real, reversed, and reduced.

In this shadow camera it is attempted to fall right on the film plate which has a very sensitive nature to light. If the light-sensitive film plate is subjected to light then the film plate undergoes a chemical change according to the light and the object in front of the camera. This plate is still light-sensitive, so that the film plate becomes insensitive to the light in the studio needs to be washed or put in certain chemical solutions. After the film plate is washed or inserted into the chemical solution, the film plate becomes non-viscous and a visible image on the film plate is called a negative image (film negative).

To get an image that matches the original image taken in front of the camera, the negative film is then printed on the film paper (usually white film paper). Images on film paper are images and objects taken in front of the camera and are called positive images. The positive image depends very much on the shadow formation process on this film plate, if the shadow occurs on the film plate is blurred or less obviously causing the prints to be later blurred or unclear.

To get good shots, you can slide back and forth until the clearest shadow with the right distance, and then you press the shutter button.

The film plate uses a celluloid plate coated with gelatin and silver bromide to produce a negative. After washing, the negative is used to produce a positive image (original image) on photo paper. Photo paper is a paper that is covered with a thin layer of colodium mixed with silver chloride. The image generated on the transparent plane is called the diapositive image.

4. LUP

An optical device consisting of a convex lens (positive lens). The loop works to enlarge small objects that can still be seen with the naked eye. The shadow properties generated by the loop are virtual, erect, and enlarged.

A loop or magnifying glass is an optical device consisting of a convex lens. The loop is used to look at small objects in order to appear larger and clearer. There are 2 ways to use the loop, ie with accomodated eyes and with unaccommodated eyes.

At the time the eye has not yet used the loop, the object is clearly visible when placed at the point near the observer (s = sn) so that the eye sees the object with the angle of view α. In Fig. (B), an observer uses a loop where the object is placed between points O and F (in space I) and the image is located at the point near the observer's eye (s' = sn). Since the eye's viewpoint becomes larger, ie β, the observer's eye is maximum.

Using a loop to observe objects with a maximum accomodated eye quickly causes fatigue. Therefore, observation by using a loop should be done with an unaccommodated eye (eyes in a relaxed state).

In everyday life, the loop is usually used by watchmakers, cloth merchants, diamond traders, police, and so on.


Optical tool that serves to see objects that are very far away, so it looks closer and clearer.


OPERATING BIAS: Binoculars that use objective lenses to refract light eg binoculars, earth binoculars, binoculars, and binoculars.

The observed object lies at an infinitely distant point, so that the shadow formed by the objective lens is precisely at its focal point. The shadows formed by the objective lens are objects to the ocular lens. The ocular lens serves as a loop.

The objective lens has a longer focus than the ocular lens (the ocular lens is stronger than the objective lens). This is intended to obtain a clear and large image. The shadow formed by the objective lens is always real, inverted, and minimized. The image formed by the ocular lens is virtual, inverted, and reduced to the observed object. As with the microscope, binoculars can also be used with maximum accomodated eyes and with unaccommodated eyes.

PANTUL OPTIONS: Binoculars that use large concave mirrors as an objective to reflect light, such as astronomical reflection binoculars.

Because the way the light inside the binoculars by way of bouncing then these binoculars are called binoculars reflection. In the reflective binoculars, the light coming is collected by a large curved mirror. The light is then reflected into the observer's eye by one or more smaller mirrors.

B. Teropong Binoculars / Earth Binoculars

Field binoculars are used to observe distant objects on the surface of the earth. Earth's binoculars consist of three convex lenses, each as an objective lens, an inverting lens, and an ocular lens. The inverting lens is only to invert the shadow formed by the objective lens, not to enlarge the shadow.

The ocular lens serves as a loop. Since the inverting lens is only for reversing the shadows, the shadows formed by the objective lens must lie at the center of the curvature of the inverting lens. Ocular lenses are also made stronger than the objective lens. Earth or field binoculars are actually the same as binoculars that are equipped with an inverting lens.

The shadow properties formed by field binoculars are virtual, erect, and enlarged.

There are earth binoculars that only use two lenses (binoculars stage), the convex lens as an objective lens and a concave lens as an ocular lens. The concave lens here serves as a inverted shadow formed by the objective lens and simultaneously as a loop.

The shadow properties are shaped virtual, erect, and enlarged rather than the shadows formed by the objective lens. These binoculars are often called binoculars or Dutch binoculars or Galileo binoculars.

Earth binoculars and stage binoculars can not be made practical. For that, made other binoculars that function the same but very practical, namely prism binoculars. Called prism binoculars because the binoculars are used two prisms near a cross between the objective lens and the ocular lens so that the final shadow formed is virtual, upright, and enlarged.
Binoculars or telescopes are tools used to see distant objects to make them appear clearer and closer. Judging from the object, binoculars are divided into two, namely binoculars and teropong terrain.

A. Telescope

Star binoculars are binoculars that are used to view or observe celestial bodies, such as stars, planets, and satellites. Another name of binoculars is the astronomy binoculars. Judging from the way the light, binoculars distinguished stars into two, namely binoculars and reflective binoculars reflection.


The periscope is a binoculars on a submarine that is used to observe objects at sea level. The periscope consists of 2 convex lenses and 2 prisms on the same foot.

The rays on the periscope are as follows: 

ɸ Aligned rays from distant objects to the objective lens.

ɸ P1 prism reflects light from the objective lens to the P2 prism. 

ɸ By the P2 prism the rays are reflected again and crossed in front of the ocular lens right at the focal point of the ocular lens. 


The slide projector is a tool used to project a diapositive image to obtain a real and enlarged image on the screen. Important parts of the slide projector include small lights that emit strong rays through the center of glass, concave mirrors that serve as light reflectors, convex lenses to form shadows on the screen, and slides or diapositive images.


This tool is used to check the retina of the eye. In the picture illustrates the important parts of the optalmoskup. The light beam coming from the light source S located at the focus of the L1 lens is aligned parallel to the mirror C. of the reflected beam C mirror to the amta. Then the doctor can observe the retina through the hole in the middle of the C mirror and the L2 lens acts as a loop.


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