Reading & Literacy

Teaching Your Child to Read

Literacy is the most important skill that elementary school students can learn. Without the ability to read, it will be very difficult for a student to succeed in other academic subjects. Because of this, teachers cannot afford to make mistakes during reading instruction. The stakes are just that high. Prison officials calculate the number of cells that they will need based on the number of children that cannot read on grade level by 3rd grade. Think about that for a moment.

Why do they do it? Because if you cannot read on grade level by 3rd grade, you are at a very high risk of falling behind academically. If you can not read the subject matter presented to you, chances are you won’t be able to succeed academically. You will never catch up, and eventually, you will probably drop out, and end up in the school to prison pipeline. All because your reading ability never quite caught up with your grade level.

Are you a parent looking to teach your child to read, or supplement the reading instruction that their eacher is providing in the classroom. I just found this amazing video on teaching children to read on YouTube. Learn how to teach your child to read with research-based, modern strategies!

Filmmaking 101: Set Sizes & Camera Perspectives

Today we’re going to look at the shot sizes and the coolest camera angles for videos. This will give you more variety in your videos in the future and create more excitement.

In the following post you will learn all the “textbook setting sizes” and get a few additional camera angles, which we like to use the most.

Why different settings and perspectives?

First, let’s ask ourselves why different camera perspectives are so important. There are essentially 4 reasons for this.

Number 1: Complexity: With different camera angles you create more complexity and viewers* can see your scene from different angles. This gives them a better understanding of the situation and allows them to follow the content better.

Number 2: You’ll have it easier afterwards in the cut! If you make sure to film different perspectives when filming your projects, you can build a story on it, have more choice and always have a good take!

Number 3: Emotions: Different camera angles create different emotions. On the one hand you can illustrate the feelings of the actors but also trigger certain emotions in the audience. This effect is often known from horror films, but more on that later.

Number 4: Always the same picture or shot often seems more boring or sad. In most cases, this is not necessarily the goal, but it can also be used consciously if you want to convey these emotions.

Now that we know why you should use different camera angles and settings, let’s jump straight into our top 10 settings and explain when to use them. A little disclaimer first, after the “textbook settings” we’re looking at a few more variations to get even more out of our videos.

Shot size: The super long shot

The super long shot or in English the “wide shot” is often used at the beginning of a scene as an “establishing shot”. Here viewers should get an overall impression of the environment and understand where the scene takes place. In addition, you can also make the main motif appear lost with a super long shot and thus convey emotions such as loneliness. This shot is typically captured on a cine zoom lens, allowing for maximum capture of the surroundings.

Setting size: The long shot

The long shot or in English the “long shot” is also often used for an “establishing shot”. Here, however, one would like to consciously direct a greater focus on the main motif and often even fills almost the entire image height with it. In addition, this setting does not look quite as lost as the super long shot and is best shot with a longer focal length in combination with a greater distance.

Shot Size: The medium long shot

The medium long shot is often used to show the holistic actions of a person. The main motif fills the entire height of the screen from head to toe and you can see all movements in detail. This setting is best achieved with a rather larger distance and a medium focal length.

Shot Size: The American “Cowboy Shot”

The American or in English the “Cowboy-Shot” shows the main subject from the knee up. The old cowboy western films were decisive for the naming. Here they wanted a shot that was as close as possible, but which still shows the cowboys’ revolvers in their holsters. Logically, this setting is used when details in the hip area are to be seen, such as a revolver. So you can think that the use of this setting size is limited. Just like the medium long shot, this shot is filmed with a rather longer distance and a medium focal length.

Setting size: The medium close-up

The medium shot is usually from the waist up and thus shows the entire upper body of a person. So you can follow the actions or the spoken text of this person particularly well and are not too distracted by the environment. We use this setting a lot for interviews with a focal length of about 50mm on a full frame camera. In this way we achieve a comfortable setting, since this setting corresponds to the human eye with a natural distance from the main object.

Setting size: The Nahe

From the medium close-up you can also get a little closer and capture about half of a person’s upper body. This creates the so-called Nahe or in English “Medium-Close-Up-Shot). Here you look the main subject straight in the eye and feel like you are part of the scene because the distance to the subject is unnaturally close.

Setting size: The close-up

The close-up shot is our second favorite setting for interviews or talking-head videos. Here you film from about the shoulder up to the hair and thus fill the entire format. In addition to dialogues, this setting is also suitable for emotional interaction between people. Close-ups tend to be filmed in higher focal lengths between 70 and 100mm.

Shot size: The detail shot

Next, let’s look at the detail shot or the “extreme close-up shot”. This is used to direct the viewer’s focus to a specific detail, such as eyes, mouth or objects. So you can not only create variety in the picture, but also build a story. With detail shots, you should make sure that the focus on the detail is clear, and a key visual should fill the entire screen. Detail shots are also filmed with higher focal lengths between 70 and 100mm.

Over The Shoulder Shot

At this point we are theoretically done with the classic “setting sizes”, but you can get a little more out of videos with camera perspectives and angles, which is why we are now taking a closer look at a few variants.

Another very popular camera perspective is the so-called “over the shoulder shot”, which, as the name suggests, is filmed over a person’s shoulder. This shot can be used to accompany a person in motion or to film a conversation between two people. Depending on the main object, you can switch between wide-angle or telephoto to adjust the setting.

POV Shot

The last shot we look at is the POV, or Point of View shot, where the viewer is allowed to see what is happening through the eyes of the main character. This makes you feel like you are in the action and part of what is happening. This setting is often seen in action films when characters look through binoculars or night vision goggles. In addition, a slight shaking of the camera is often used here to make the picture more authentic.

Tips on setting sizes

So those were our top 10 shots and angles. Anyone who has made it this far will of course get a few helpful tips on how to create emotions. Different camera perspectives can be used to create emotions. As already explained at the beginning, you can, for example, depict a person as lost if they can be seen alone in a super long shot. In addition, you can also use other tricks, such as the height or the orientation of the camera.

For example, if the camera is set significantly lower than your main subject, the person will appear larger, more powerful and stronger. Exactly the opposite is logically the case when you align your camera above eye level. As a result, the filmed person appears smaller, weaker and perhaps overwhelmed with a situation. You can always use this trick if you want to make a person appear particularly strong or weak.

You can also work with the alignment of your camera. As you may have seen in our composition post , we usually always try to align our camera parallel to the horizon or lines in the image. However, you can also deviate from this in order to obtain the so-called “Dutch Angle”. The Duch Angle is often used in movies to show that the situation is scary, weird, or unpredictable. The camera is turned so that it no longer runs parallel to the lines in the picture in order to make the viewer feel uncomfortable. This setting is particularly popular in horror or action films, where the camera is rotated from a few degrees to a completely oblique view.

Variety: You now know different setting sizes and camera perspectives, try incorporating these different sizes into your next video. We often shoot the same scene in different settings in order to be able to access more selection later in the editing process, which often also helps to create a nice story and consistency. You should also be careful not to use the same setting too often in a row, otherwise a scene could quickly become boring.

Avoid axis jumps: If two people are talking to each other in a scene, cameras should always be positioned on one side of the two people. This makes the image appear more logical in the later video, since usually one person is always looking to the left and one to the right. If you were to position a camera on the other side, both people would be looking in the same direction. And as you can imagine, it looks pretty weird. By the way, if you come across this in English, it’s called the 180 Degree Rule.

Watch: The next tip we want to give you is watch! The next time you watch a film, pay attention to which settings and camera perspectives are used, you can often see completely new approaches here and you can pick up one or the other cool shot. 😉

Don’t always follow the textbook: And now very important: you don’t always have to follow the textbook. Especially with the setting sizes, there is constant discussion back and forth as to when a long shot becomes a super long shot and how much variety is really needed in the perspectives. Don’t let that put you off and if in doubt, just see if you like the picture and the overall concept. Sometimes it’s really cool to keep a shot longer or deliberately use a weird framing.

Conclusion: Setting sizes and camera perspectives when filming

In summary, it can be said that there are a variety of setting sizes and camera perspectives that you can freely combine with each other. Of course, you can not only create different emotions with the setting size, but also work with the orientation of your camera. Sometimes it makes sense to break the rules. Just look at Lord of the Rings. Here an axis jump is used more often to show that the character Gollum is talking to his alter ego.

So now I hope that you got a good overview of the setting sizes and camera angles. You now know the basics and know how to use different settings. We wish you a lot of fun trying it out!

Lens: Main optical part of any microscope

The main optical part of any microscope is the lens. It consists of a complex, centered lens system that provides a correct, magnified inverse image of the subject.

The front lens of the objective (spherical or hemispherical) that magnifies the image is called the front lens. The lenses lying behind it – corrective ones – correct the image by eliminating imperfections – artifacts (aberrations) created by the front lens.

The focal length of the lens for rays of different wavelengths is different. Therefore, when using non-monochromatic light, the image of the object formed by the lens has colored edges. This phenomenon is known as chromatic aberration; it is eliminated by achromatic and apochromatic lenses. The difference in the optical properties of the central and peripheral parts of a spherical lens causes spherical aberrations; they are eliminated by apochromatic lenses. Currently, to eliminate this drawback, special lenses are used – planachromats and planapochromats. In bacteriological practice, the most widely used lenses are apochromats, achromats and planochromats. Such a subdivision of lenses is carried out according to the nature of the correction of aberrations, i.e. defects in the image of optical systems.

An Introduction to the Light Microscope, Light Microscopy Techniques and  Applications | Technology Networks

When using apochromatic lenses, chromatic aberration is almost completely absent, i.e. decomposition of white color into components of the spectrum. Consequently, conditions are created for the most correct transfer of the color of the object. This property is provided due to the complexity of optics (up to 10-12 lenses) and the use of special glasses of different chemical composition.

More common are achromats, in which chromatic aberration has been partially eliminated. These lenses contain up to 6 lenses and produce an image that is sharpest in the center.

When microscopy of colored objects using achromats, a yellowish or greenish background may appear around the image. When microphotographing, it is advisable to use planochromats. Planochromats completely eliminate the curvature of the visual field up to the edges.

Each lens is characterized by the following basic constants: focal length, magnification, resolving power, numerical aperture, effective aperture. The native magnification of the lenses is indicated on the frame (8, 10, 20, 40, 60, 90, 100). On some lenses, instead of magnification, the focal length is indicated in millimeters (16; 8; 5; 1.5 mm, etc.). The shorter the focal length of the objective (the front lens facing the preparation), the greater its magnification. According to the focal length, lenses are divided into strong (F = 5-1.5 mm), medium (F = 5-12 mm) and weak (F = 25-30-50 mm). Resolution of the lens, i.e. the property of depicting the smallest details of the preparation, is characterized by the smallest distance at which two closely spaced points are distinguished. Resolution is determined by the formula:


where E is the resolution of the lens;

λ is the length of the light wave;

A – numerical aperture.

Numerical aperture (“coverage” of the lens) is the product of the refractive index of the medium separating the object from the front lens of the microscope objective by the sine of the aperture angle.

According to the method of use, lenses are dry and immersion, i.e., immersed. Dry lenses are those in which there is air between the front lens and the preparation. These lenses are characterized by low magnification and relatively long focal lengths.

Some lens specifications are engraved on their frame. TO

they include (Fig. 2 and 3):

– increase (4, 10, 40, 100, etc.),

– aperture (0.12; 0.30; 0.65; 1.25),

– length of the tube (160, etc.),

– thickness of the cover glass (0.17),

– type of immersion (MI – oil immersion – black rim, VI – water immersion – white rim)

When microscopy with strong lenses, the focal length of which is small, it is necessary to create a homogeneous optical medium between the front lens of the objective and the preparation glass. This is achieved by immersing the lens in a drop of cedar oil on the preparation. Cedar oil has a refractive index of n = 1.510, close to that of glass. In this regard, the light beam leaving the glass is not scattered and, without changing its direction, enters the lens, providing good illumination. Peach oil (n = 1.471-1.498), a mixture of castor and dill oils (n = 1.474-1.498), etc. can be used as substitutes for cedar oil.

Ultimate guide for choosing a machine vision lens

Most present day applications use fixed focal length lenses with fixed least community distances (MODs), as these limits all around don’t shift almost anything. Expected for an obvious development, they give an optimal picture. Of course, there are fixed focal length lenses with a focusing unit that allows the MOD worth to be changed insignificantly. In view of the legitimate focal length, these lenses offer a fairly static intensification territory. For more prominent consistent quality, metal lodgings are used, which are by and large used for most machine vision lenses.

Basic considerations in choosing a machine vision lens

There is a prompt association between the sensor used in the camera and the most fitting lens. Limits, for instance, sensor size and pixel size are essential. The lens ought to have the choice to edify the entire surface of the sensor to avoid covering and vignetting. It ought to moreover have the choice to decide the pixel size. The higher the optical objective of a lens, the more unmistakable the plans recreated.

Optical Lenses - DZO - DZO东正光学官网

The optical idea of a lens is directed by the change move work (MTF) which describes the separation as a part of the fineness of the nuances to be recreated. It portrays mathematically the assessment between the separation of nuances at the edges of the article and the distinction of nuances on the image. To ensure the depiction of the nuances of an article and the unambiguous ID of the edges, the detail ought to be copied on around 4 pixels. Thusly, the enhancement required depends upon the essential objective of the thing and the looking at pixel size. The ideal machine vision lens should copy an image that immaculately facilitates with the thing, recalling all nuances and assortments for brightness. All things considered, this is seldom absolutely possible, considering the way that lenses go probably as low-pass channels. The proportion of debilitating of some irregular repeat or detail is gathered the extent that MTF (picture 1), and for any lens there is where the equilibrium is zero. This cutoff is generally insinuated quite far and is for the most part conveyed in line matches per millimeter (lp/mm). Obviously, with the enormous extent of sensor associations and objectives available in machine vision, and the huge number of possible applications, there is furthermore an especially wide choice of lenses, including numerous very specific lenses.

The most ordinarily used machine vision lenses

The most typically used sort of lens for sensors with an objective of not by and large around one megapixel is the far reaching lens with a standard fixed focal length of 4.5 to 100 mm. These lenses are upgraded for vastness focusing and have a MTF of 70 to 90 lp/mm with little bending and vignetting. More restricted focal length lenses all things considered produce “fisheye” twisting pictures.

Exactness lenses, significant standard types of standard lenses, offer ideal audit execution over standard lenses. They are overall open with focal lengths up to 75 mm, MTF more than 120 lp/mm and incredibly low twisting (<0.1%). They are particularly proper for cameras with little pixel sizes or for careful assessment applications.

Full scale lenses are available for little fields of view, about the size of the sensor. Demonstrated the extent that enhancement similar with the camera sensor, they are redesigned for “close-up” focusing. Regardless of the way that they have marvelous MTF credits and immaterial mutilation, they need flexibility since it is past the domain of creative mind to hope to change the opening or working distance.

At the contrary completion of the scale are colossal association lenses, which are required when the sensor estimations outperform those possible with a C-mount lens. They are ordinarily estimated, including different parts, for instance, focus connectors, helical mounts and spacers.

Telecentric lenses are used specifically metrology applications to avoid layered and numerical assortments in pictures. These lenses don’t encounter the evil impacts of mutilation since they collimate the light that enters them. This results in pictures with consistent enhancement, paying little psyche to fight distance, without perspective twisting. Because of the equivalent bar way, the hole at the front of the telecentric lens ought to have basically a comparable distance across as the field of view. lenses for immense fields of view are therefore greater and thusly by and large exorbitant.

New in the field of lenses, electrically adjustable liquid lenses convey many advantages to machine vision. They are made from a petite adaptable polymer film containing an optical liquid that licenses them to change shape (picture 2). An actuator obliged by electrical pulses presses the liquid inside the lens according to an outer viewpoint, changing its shape and allowing exceptionally short response periods of a few milliseconds. They are particularly useful in applications where there is a need to change concentrate quickly, for example while evaluating compartments of different heights on transports. This exceptional standard considers faster and more limited optical structures without complex mechanics. An astonishing MTBF (Mean Time Between Disappointments) of more than one billion improvements is proof of a very long system life, as the modified difference in the lens mitigates various pieces of any turn of events. This optical contraption is a sensible advantage for machine vision, especially for 3D microscopy or observation tasks.

360° lenses – A couple of utilizations require something past a camera. For example, the examination of perplexing things with express shapes requires sees from different places. Therefore, there are novel 360° lenses, which, with the help of a creative party of lenses and mirrors, get the article from all of its highlights in a base number of shots. The top and sides of a thing, the back and inside an unfilled article or one with an opening, different sides: this lens grants to aggregate this heap of points of view in a solitary picture. This development helps various regions, similar to the medication business, the auto business or in the food business, especially for drinks.

For round and empty articles, similar to containers, glasses, batteries or bolts, pericentric lenses are generally proper to get their specificities. Considering the particular method of light pillars through the perspective, light from the piece of the thing closest to the lens falls in the lens of the sensor, while the farther parts are shown on the edges. The top and side appearances of the thing are as such trapped in a singular shot, with the side points of view on the article including the top face in the resulting (picture 3). A common application in the medication and drink industry is the assessment of the neck series of holders and the scrutinizing of Datamatrix codes, which will reliably be examined precisely, paying little notice to its arranging. The more unassuming the estimation of the article, the more critical the stature of the thing that can be surveyed, while slight things can be checked on a greater width. For little articles (up to 7.5 mm in width), the usage of catadioptric lenses is recommended. These objectives are planned to see the sides of the thing with a wide perspective, close 45°, which allows the examination of perplexing article computations with adequate perspective.

An extraordinary extent of lenses for void things has in like manner been planned for the assessment of articles containing openings, melancholies or for holders, allowing the lower part of the thing similarly as its dividers to be seen. Wide point lenses (> 82°), they grant to work with a wide extent of thing breadths and thicknesses. This makes them ideal for evaluating a wide collection of shapes, similar to chambers, cones, openings, bottles or hung articles.

Another optical progression is the multi-see lenses (Polyview), which grant eight special viewpoints as an afterthought and top surfaces of an article meanwhile. The wide perspective (45°) grants the audit of the sides of an article (for instance the line of a screw or a nut). Both the outer surfaces and the upper bits of an article can be gotten meanwhile. The inside bits of a vacant article can moreover be analyzed according to an outside point of view. The depiction of the internal dividers and lower a piece of an unfilled article is also essentially as possible as a joined point of view on the inward and outer dividers of the thing.

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