Pedagogue Blog

Personalized/Adaptive Learning Apps, Tools, and Resources That I Would Use If I Were Still in the Classroom

Back in 2001, when I started as a teacher, the technology boom was in its nascent stage. I remember toting a large bag filled with papers home most nights and going to sleep drowning under a vast sea of student homework that needed grading. My classroom was even worse, cluttered with books, manipulatives, globes, maps, and learning stations that left little room for anything else. However, as I write this in 2018, things have changed dramatically. Today’s teachers have edtech in their corners.

Digital teaching and learning tools have streamlined education processes and provide learning experiences that stretch far beyond the materials that were available for me back in 2001. Back when I was a special education teacher, the only students who had personalized learning plans where special needs students. Individualized Education Plans (IEP’s) were created for them to satisfy the requirements of IDEA (Individuals With Disabilities Acts). They were notoriously time consuming, but we never complained because it was for a good cause.

Nowadays, with the advent of personalized/adaptive learning apps, teachers can create personalized/adaptive learning experiences for all students. If I were still in the classroom today, I’d use these personalized/adaptive learning apps, tools, and resources:

Socrative: Socrative is an easy way for teachers to identify how students are doing clearly. They can assess students or offer them prepared activities to see where they are at currently and help the system make a more personalized plan.

Newsela: Newsela combines major news and research with adaptive reading materials. Split your class up into their appropriate categories and give them an article to read. You can find relevant material for every subject area so you can incorporate literacy across your entire day.

ThinkCERCA: This is a personalized literacy platform that helps teachers convey critical reasoning skills by using argumentative writing. The platform focuses on helping students aged nine to eighteen prepare for life after high school by strengthening their analytical skills in every subject. The platform makes use of standards-aligned close reading and academic writing lessons to teach English language arts, science, social studies, and mathematics.

Cerego – Cerego is a personalized learning platform that helps people learn faster, remember longer, and objectively measure their knowledge using AI-assisted predictive algorithms. It helps organizations improve productivity as employees learn better and are better motivated and more capable. The app uses predictive learning features to deliver individual specific learning materials to its users. Available on Android and iOS devices

Flipick – This app creates a personalized learning experience for every student and helps to develop curricula. It also creates an interactive and collaborative learning environment for learning to take place.

Kytabu – A textbook subscription app developed in Kenya. The app provides access to digitized versions of all Kenyan textbooks from Standard 1 to Form 4 at rates that are affordable for African families. Kytabu uses machine learning to help provide personalized learning for learners. The learners can access educational content that includes books, videos, audios, tests, as well as exams. A great advantage of the app is that it can be used offline. This is a crucial issue in Africa where internet access is limited and often unreliable.

Quizalize: Make your subject matter fun again with the adaptive learning platform offered through Quizalize. Every assessment feels more like a game, giving students the motivation to do their best. It allows you to easily identify where students are struggling so teachers can be better equipped to make a more personalized learning plan or offer more assistance.

Knowre: When it comes to STEM, many students struggle with the math component. Knowre offers an adaptive learning experience that can help bolster a student’s mathematical abilities. They offer supported practice time, fill in the gaps with a personalized review, and offer actionable data to educators.

Scootpad: With Scootpad, students get a comprehensive adaptive learning experience. It starts with practice, allowing Scootpad to meet students where they currently are. It moves on to offer more instructional content, real-time remediation, and assessments.

Freckle Education– Students can easily fall in love with schooling again as this app enables them to work in various subjects at their pace. Teachers can monitor students’ progress across various subjects such as science, social studies, math, and English language arts.

SmartEd: With this tool, you can make relevant changes to textbooks and other learning materials to suit the needs of your students. This platform also allows you to be in direct contact with your students. It uses a game-like approach, which aims to make learning look less imposing.

Did we miss any?

How Covid-19 is Creating a Global Education Crisis

While the novel coronavirus has brought the entire world to a standstill, it’s the education sector that will suffer the most consequences. Almost all across the globe, the closure of schools, and universities, has darkened the clouds over the future of many young and adult students.

But if schools and colleges are allowed to open, the pandemic may continue for years to come. Besides, there are little to no preventative procedures in place to avoid this eventuality. Moreover, we are not even sure if fever detection will suffice, or if more is required to ensure the well being of children.

So, let’s dive into how the COVID pandemic has brought about an educational crisis.

Implications of COVID-19 for K-12

Many of the K-12 students educated from 2020 to 2021 will be missing up to 2 years of foundational academic skills. A lot of these babies will be 8-10 years old before they start to read picture books—what a sobering epiphany.

As per UNESCO, 1.6 billion children in 191 countries have been impacted by COVID-19. Though the closures are in the interest of safeguarding children’s health, it is also a reality that not every kid can learn via remote learning.

Besides this, there are K-12 kids from across various societal strata who are now deprived of nutritional school meals, which are otherwise unaffordable for them. And while there is a need to ensure connectivity, extra attention, and support for their parents, the task is easier said than done.

In the U.S., many schools are starting to reopen, either with an on-time or delayed start to the 2020-2021 school year. Some have decided to go back to all face to face courses, some have embraced a blended approach, and others have decided to start the school year with fully online courses. No matter how they start, most of their students will end up getting left behind.

For the college level students

College students are also negatively impacted by the pandemic. While their classes were shifted online, many were forced to go back home, with little to no internet connectivity. Some had no home to go to.

This fall, many of these students are gearing to go back to college, and just like K-12 schools, Some have decided to go back to all face to face courses, some have embraced a blended approach, and others have decided to start the school year with fully online courses. No matter how they start, most of their students will end up matriculating and then graduating without the skills that they need to succeed in their chosen profession.

Tapping into the power and promise of digital resources

However, hopefully, taken, this could mean that – now is the time to turn challenges into opportunities!

Though governmental and non-governmental bodies will have to strive hard to provide technological access, it may change the education paradigm. Before there was COVID-19, there were still millions of kids, who are deprived of formal education. Yet, the current pandemic has opened a pandora’s box where and shined a spotlight on these “savage inequities.” Many cash strapped schools have been turning to free digital and OER (Open Education Resources) to provide the curriculum and resources that they need to educate their students.

It’s not just the kids but also the teachers who need better training and access to quality materials. But while teachers must be encouraged via incentives, societal honors, and more, they must be selected through a thorough proper vetting process. And they must also be encouraged to continue learning via professional development.

With digital resources and online classes, we can tap into the power and promise of the internet. Who knows, remote learning may also turn out to be a novel medium to strengthen student-teacher interaction.

Concluding thoughts

We have established that the pandemic is creating a global education crisis. The question is, how do we respond to it in a way that will produce positive student outcomes?

I Bet You Didn’t Know This About Your Brain

Developments in neuroscience have significantly changed how we think about the brain. What we have learned in the 21st century about this organ had had incredible implications for education and the inclusion of technology in our instruction.

Educators have had to unlearn some of what they learned about brain theory in light of new developments. As a result, some of our education practices have had to change with them.

Technology alters the brain

Our love for technology has changed the way our brains work. Attention spans have shortened, and heavy tech users seem to be more forgetful than those who only occasionally turn to technology. In addition, we’re witnessing the atrophy of our socialization skills thanks to excessive technology use. Focusing exclusively on technology dehumanizes us.

This revelation requires more novel instructional approaches to learning. Educators must incorporate non-tech activities in less to help the brain rest and recover from excessive technology stimulation. Turn to discussion groups, nature walks, and collaborative activities that require socialization with others. Teachers who include other brain-based strategies are maximizing learning opportunities for their students.

Brain damage doesn’t have to be permanent

Researchers once thought that brain injuries were a permanent condition. In some cases, such as a stroke, they may be. The brain can heal from more minor injuries, however, like concussions. That’s because the brain has plasticity. The neurons firing inside the brain can be reshaped as necessary. These neurons are continually growing, pruning, and adapting themselves. Over time, they either heal or create new neural pathways for thinking, learning, and living. The brain compensates for the damage by working around it.

The implication for learning is enormous. Brain damage does not have to prevent anyone from being a student. Learning is a life-life endeavor, regardless of mishaps along the way. We can change not only how we think, but also the way we think.

Your brain is balanced

We once thought of the brain as two parts. We divided up tasks as left brain-right brain activities. The left brain was analytical and orderly, a quiet organ for lengthy calculations and problem-solving. The right brain was the eternal party room, where creativity experimented with innovation at all hours of the day and night. We even categorized people as left-brain or right-brain thinkers who had a neural preference for everything, including how they organized their closets and went about their work. 

Now we know that the brain works simultaneously in two ways. This flexibility is a balance between order and chaos. The brain relies on mathematical relationships, but it also uses flexible thinking to make inferences, deduce thoughts, and solve problems. This discovery may affect our ability to create authentic artificial intelligence.

The brain is responsive to positive stimuli

And finally, the best thing you can do for your brain (and your mood) is smile. UK researchers discovered that a smile could be just as effective in raising your levels of serotonin as eating 2,000 chocolate bars or getting $25,000.  Smiling improves your mood and your outlook.

That’s something to consider the next time you’re under a lot of stress or working hard on a project.

What’s the Blueprint For a Smart College Campus

In order for college campuses to meet the needs of a changing society in the midst of countless concurrent technological revolutions, it is imperative that the universities of tomorrow boast “smart” campuses. A “smart” college campus needs to put students first and their interconnected learning experiences at the forefront.

In order for a “smart” college campus to stay relevant for upcoming decades and through a host of technological and learning paradigm shifts, the institutional norms of past universities must be left in the past. In their wake, a new type of campus that embraces community and immersive learning spaces will serve a student populace headed into a job market where soft skills are valued first and foremost.

Ending The Classroom In Favor Of More Adept Learning Spaces

The age of the traditional lecture hall has come and passed. The primary heartbeat of a “smart” college campus needs to eschew such an archaic model in favor of learning studios that facilitate group work and a sense of a learning community. 

To complement these learning spaces, comfortable furniture and teachers with adaptable teaching styles are imperative for making it work. We need to make the college of tomorrow inviting to students. In doing so, we can break down the walls that traditional education has built by giving students a safe space to really stretch their intellects.

Furthermore, all of the learning spaces and connected spaces within a “smart” college campus must be networked and connected to the Internet of Things. There is no use shying away from technology and the impact it has and will have on a changing student populace. 

Connecting Your Campus To Connect With Your Students

Every space on a “smart” college campus needs to be an intuitive rethink of the traditional spaces on a college campus. The library can’t simply be a place to check out books anymore.

Rather, a “smart” college campus will have a library that brings all the best elements of a traditional one and adds an interconnected element. Curating infographics, multimedia sources, and even providing a virtual study environment for students to immerse themselves in will be crucial in reimagining what a library could and should be for students of the future.

Even academic offices will need to be rethought in hopes of bringing professors closer to students by cutting down on the red tape that causes dissonance on traditional college campuses. A “smart” college campus will be an empathetic one. It will foster a sense of community among its professors, administrators, and students.

Rather than relying on office buildings, a “smart” college campus will have collaborative workspaces that serve to encourage free thought and discourse.

Concluding Thoughts

The blueprint for a “smart” college campus needs to put away traditional administrative ideals in favor of embracing the changing needs of society. For a college campus to survive and thrive in this new age, we must put archaic structures aside in favor of spaces that encourage active and interconnected modes of learning. 

7 Ways to Measure Student Growth

I define student growth as academic progress that is accomplished over a period, as assessed at the onset and end of a specified time. It can be calculated for countries, states, cities, schools, or students, and many variables and strategies can be used to determine if “growth” has occurred. Sounds easy, right. Not exactly. Many school districts and even state departments of education have difficulty measuring student growth. If you fall into this category, don’t worry, we have your back. In this article, we will discuss seven ways to measure student growth.

The Computer-Adaptive Approach

This approach allows educators to view student growth over a single year, as opposed to multiple years, on the same scale. Computer adaptive assessments will adjust their difficulty based on a student’s performance.

The Student Growth Percentile Approach

This approach compares a student’s growth to students with similar test scores. The benefit of this approach is that it allows us to fairly compare students who start at different levels with similar students.

The Value-Added Approach

This approach measures the teacher’s effectiveness in a given year by comparing the current test scores of their students to the scores of those same students in prior school years. Value-added models are considered fairer than other models since it takes confounding context variables like past performance, student status, or family income status into consideration.

The VAM – Covariate Adjusted Approach

In this approach, student academic growth is calculated by juxtaposing students’ predicted scores with their genuine scores. One of the drawbacks of this approach is that you will need several years of “matched” data for accuracy.

The Gain Score Approach

This approach measures year-to-year change by subtracting the year before an (initial) score from the current year (final) score. The growth of a teacher is averaged and compared to the overall average growth for other teachers. It’s easy to calculate and can be used with local assessments. The issue is that it doesn’t make accommodations for initial achievement levels; it’s just a run of the mill calculation of the change in score for students.

The Effect Size Approach

The effect size approach allows you to compute the amount of the difference between two groups. With this approach, if a teacher gets an effect size of +1.0, their students grew one standard deviation.

The Progress Monitoring Approach

This approach is different from your usual criterion-referenced assessments because they are not normed. They’re easy to administer, and the data can be shown to explain the difference between where the student is performing relative to the expected target or level.

Can you think of any additional ways that we can measure student growth?

Social Networking Apps, Tools, and Resources That We Love

Are you looking for social networking apps, tools, and resources that you can use with your students? If so, we have you covered. Check out our list below. Let us know if there are any that we missed.

Edmodo– While social networking has received its fair share of criticism about the bad influence it tolerates, this app is unlike all that. Edmodo is a powerful tool that can be used to pool the creative thinking of students. It helps them think critically while fostering student-teacher partnerships to create projects.

EduStruct– This platform creates a virtual learning structure for elementary and higher learning institutions. The platform provides a social networking service for schools to create and manage their content to be globally relevant.

Quiz ME Online– QuizMe Online is a social networking website that allows students and teachers to come together to achieve success. The site is built on the belief that when students, teachers, and others with an educational interest come together to accomplish a common goal, each student has a better chance at achieving their resolutions.

Meetup– If you have a hobby or something you would love to share with others, you can use the Meetup app to get the word out. This is the largest group networking app available; all you do is collaborate with other members and meet up face-to-face for discussions or group outings. Whether you love archery, knitting, writing, or collecting rare Star Wars figurines, there may be hundreds of groups in your area just waiting for you to join.

Bookopolis Book Search– This is a social network for young readers with a built-in book discovery feature. Teachers can use this platform to build a society of readers and writers from their classes. Students can partake in book reviews and critical thinking to develop opinion writing. Teachers can track and critique a student’s work. The BookQuest option is useful for finding new book reading suggestions.

eChalk A simple K-12 app platform used to guide and pass out information. It provides an enabling environment for users to have access to an all-in-one learning tool, encouraging teamwork in a professional level. Teachers can use this app to distribute information to parents and the community at large using email and a secured social network.

edWeb– A social network of school administrators, educators, and stakeholders. This is a forum where educators share, learn, and devise new ways to foster better education for students. Educators can join this platform for free, and they can create their network of people with whom they share ideas and innovations. The edWeb network has over 75,000 members and more than online 800 societies.

Mendeley– Mendeley is a social network that allows you to organize your documents, references, research, and papers with a quick click. You can even collaborate with other users through this software, making it your productivity hub.

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.

Trekking bike: particularly suitable for all riders

A trekking bike is particularly suitable for all riders who like to go on extensive leisure trips and who want to use it on their daily commute to work. The ground becomes secondary: the trekking bike likes to ride on gravel as well as on asphalt. Especially if you are unsure about the right bike and need an e-bike for all purposes, you are well advised to go with the trekking bike.

The real all-rounders also provide increased driving comfort and usually meet all safety requirements in road traffic. Therefore, this type of bike is one of the most sought after on the market. However, you should consider the range of trekking e-bikes. Since it offers a wide range of possible uses, manufacturers often rely on specific properties that position the trekking e-bike more off-road or more on the road. The same applies to the balance between sportiness and comfort.

What should I look out for when buying a trekking e-bike?

You should pay attention to a few features so that you can fully enjoy your trekking e-bike. Although most bikes from the top manufacturers meet all the requirements for everyday and leisure use, there are still some differences in equipment and also in the type of trekking bikes. There are offers up to cross e- bikes , which are more aimed at off-road oriented riders, and there are everyday bikes with the option for occasional excursions, which are more aimed at leisurely occasional riders.

The drive systems

When it comes to the drive, you should make sure that the motor has enough power to support you occasionally on the mountain. The torque of the engine is mainly responsible for the thrust on the hill. From 60 Newton meters you have enough power on the bike even on more demanding climbs. Another important component is the battery.

People like to go on longer tours with trekking e-bikes, which is why a battery with the highest possible capacity is important. We therefore recommend at least 500 watt hours, even better you are equipped with over 600 watt hours or even a combined capacity. Since you often take luggage and drinks with you on trekking bikes, models with integrated frame batteries are ideal. This leaves enough storage space for other utensils within your frame.

Your drive should also offer different support levels that you can easily operate. Since the use of trekking e-bikes is so versatile, the demands on the motor are constantly changing. 


The focus of the trekking e-bike is on comfort, so a stable frame with a comfortable seating position is very important. Depending on your height and mobility, you can choose between diamond frames with a high top tube and trapezoidal frames with a low top tube on many trekking bikes . The second makes it easier to get started, but offers slightly less stability.

Whether your trekking bike needs a suspension fork depends on your route preferences and your need for comfort. A suspension fork absorbs vibrations and is therefore useful if you travel a lot off-road. For the daily commute on asphalt, you might be able to save yourself the suspension fork.

What is particularly practical about many trekking e-bikes is that the frames come with the right holders for bags, trailers and accessories. Luggage racks and mudguards can be easily attached and detached if necessary, making the bike even more flexible.

Other parts

You should also pay attention to a good braking system, especially if you often ride downhill and quickly. Nevertheless, the disc brake is a suitable choice here.

When it comes to tires, puncture resistance is what counts most. Different manufacturers offer different qualities. A good tip is the G-Force T42. However, you can also retrofit these if the installed tires are worn or broken. Furthermore, the tire should not be too narrow and have enough profile so that you still have enough grip on unpaved paths.

Our trekking e-bike recommendations

As with all bicycles, the following applies to trekking bikes: quality has its price. A good trekking bike will last a long time, so you can consider it a long-term investment. High-end bikes offer exceptionally good suspension, hydraulic disc brakes, puncture-proof tires and high -quality gears. So that you can also commute by bike at night and in winter, you should also attach importance to a high-quality lighting system .

In the lower price segment there are mainly trekking e-bikes, which are more reminiscent of city bikes.

Given the wide range of uses for trekking bikes, it usually makes no sense to make specific recommendations. Because in addition to the intended use, your own preference also plays a major role in the selection. You should therefore consider which frame shape you prefer, whether you want suspension or what range you want your new bike to have. 

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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How to safely clean the sensor of your DSLR?


We present to you today a really useful tutorial. We will show you how to properly clean your DSLR sensor step by step, in a 100% reliable method that you can apply yourself at home, in just a few minutes. To clean the camera sensor, the most reliable and popular method has been chosen today: dry cleaning. It will allow you to clean the sensor of your device in a minute and a half watch in hand.

Step by step guide: how to clean the sensor?

One of the great fears of both amateur and professional photographer arises when it comes to cleaning the sensor of their SLR camera at home. We know that the sensor is a delicate part of the camera, but there are reliable, risk-free methods that leave our sensor like new in a few minutes and without leaving your home or having to carry your camera. to the technical service.

This is the case with dry cleaning, which does not use any type of liquid whatsoever, therefore without risk. This system is based on brushes with adherent properties that gently remove dirt from the . Let’s see what it is, step by step. Here we show you how to perfectly clean your sensor in three easy steps.

1. How do I know if the sensor is dirty?

The first thing to know is to make sure that the sensor is really dirty and that it needs to be cleaned. How to verify it? It’s easy: take a picture of a completely flat, even surface to identify even the smallest stain.

To take the picture, we recommend that you select the smallest possible aperture on your camera, f / 22 for example, while keeping the ISO sensitivity at a minimum, ISO 100, for example. Take a test shot by shooting a clear sky and focusing at infinity.

2. Unlock the mirror to access the sensor

According to DZOFilm, once you have verified that your sensor needs a good cleaning, it is now time to get down to it. The first thing to do is to remove the lens installed on the camera. Then go into the menu and look in the settings for the one that allows you to unlock the mirror.

All cameras have a function that allows this, with a name specific to each brand. In my case, I just had to activate the latter, then press the shutter for the mirror to rise. And I was able to access the camera’s sensor to clean it up.

Clean the sensor easily and safely

It was easy, wasn’t it? If this tutorial has been useful to you, share it with your fellow photographers so that they in turn can learn how to clean the device of their camera, in a method as reliable as dry cleaning, and very quickly too. If you have any questions or suggestions, or if you use another method to clean your camera’s sensor, please let us know below or on social media.

Keep in mind that this method is effective for clumps of dust and dirt that often appear on the device, but is not recommended for oil stains, for example.

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