How Optics Work - the basics of cameras, lenses and telescopes
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- čas přidán 14. 06. 2024
- An introduction to basic concepts in optics: why an optic is required to form an image, basic types of optics, resolution.
Contents:
00:00 - Introduction
01:44 - Pinhole camera
03:28 - Mirror optics
05:06 - Lenses
06:27 - Focus
10:17 - Resolution
Sources:
[1] James Ayscough, A short account of the eye and nature of vision (1755), archived at commons.wikimedia.org/wiki/Fi...
[2] www.nasa.gov/content/goddard/...
[3] commons.wikimedia.org/wiki/Fi...
A version of this video (and all my other educational ones) without background music is available on my DailyMotion: www.dailymotion.com/video/x891x7z
Could you just mention a couple of examples here? I clicked on that link and it just never ends with videos, and I am not going to bother with it.
Just tell me if you don’t know, instead of sending me off to some link
The mud and asphalt analogy was FUCKING BRILLIANT
Light rays have width? Analogies don't help with understanding; the two phenomena are caused for entirely different reasons, so you need to understand each reason to understand what is really going on. The irony with using analogies is that you don't even know how good or bad they are unless you know both the thing you want to understand to high levels and also understand the analogy to high levels. This enables you to compare the two and determine if the analogy is good or not
But if you need to know both to high levels, then this clearly means you already understand the thing and do not need an analogy. If you need an analogy, that means you don't know the subject enough to determine if the analogy is good. Thus, you don't understand and are just blindly going along with something
@@pyropulseIXXI Well I always thought analogies are useful to demonstrate how things behave, not why they behave the way they do. I.e now I understand that a light ray which is refracted behaves similarly to how a truck which drives through mud would behave. In my mind the quality of an analogy is determined by it's accessibility and not it's descriptiveness or detail. Of course you could call this blindly going along with something but I call it trusting the person making the analogy. If you don't want to give them the benefit of the doubt, fine but why do you give it to any other source of information then? After all isn't the metric by which you determine what and whom to trust also defined by things you have trusted in the past? So to me it seems you'll have to blindly go along with things either way if you want to do anything at all.
@@toxin1662 My field of study is physics and mathematics, and I've never found an analogy to be useful at all. _Never,_ _not once;_ they always fall short, and they often introduce erroneous understanding via text.
Analogies are of time; I learn via learning the material directly, while my 'peers' are
@@pyropulseIXXI I don't know how far you are in your field of study, but you'll realize at some point that everything in physics is some sort of analogy for reality, even down to the most elaborated mathematical descriptions.
We don't have a perfect theory for anything yet, all we have are better and better approximations, and all that matters is how useful these approximations are.
In the present case the truck analogy isn't even a bad one, as you usually use plannar waves to demonstrate refraction with the wave description of light, and these plannar waves have a spacial width
All of this is to say that i disagree with you, analogies are incredibly useful, as long as you know their limitations, and that is also true for any actual theory on anything
@@LucVignolles A model approximating reality is not an analogy. F=ma isn't an analogy; it is exact according to all human perception
I've never used an analogy to learn anything
What a great video! I can only imagine that you have a career in teaching, since you are great at explaining complex matters, so that they appear simple!
The focus and Lenses part really clicked with me as too why we only dealt with point sources, I just never knew that was all that was needed! Thanks for the nostalgia!
People's ability to emulate perception used to be nothing short of magic to me before watching this video. Thanks for providing such a succinct explanation.
Very nicely written and produced! Optics is a vast subject, and it’s mysterious to most people. But , you have demystified it and distilled it down to just 12 entertaining minutes. I’m really looking forward to what you have to say about x-Ray optics. Bravo!
That's the best video I've seen about the topic, it's just what I was looking for. I need more!
I'm reading up on visual perception for a cognitive psychology class. This was very helpful to get me around the basics of how our visual system works. Also made me realize how much our eyes (and our bodies and our brains) are doing so much work. Thank you very much for this content! 🎉
The brain doesn't invert the image. The world is actually upside down and we just think it is right side up due to the image being inverted on our retina
Only 1k views, this is great, this needs more views.
Very fascinating video with a mundane title. Should have been something like "Why telescopes use mirrors and microscopes/cameras use lenses"
That's misleading. Newtonian telescopes use mirrors, but Refractive telescopes use lenses with no mirror.
What an excellent video- covering a huge range efficiently and effectively. Concise, clear, with enough scope to give a great intro in a short time but without giving any misconceptions. Excellent work, highly underrated. Thank you.
Me and my 12 year old son really liked your video!
These videos are so clear and well presented... I hope you keep making them. Thank you very much!!!
I was always comforable with wave optics but never with ray optics because the concept of focus and "forming an image" was never clear to me. I had the factors you listed in mind but wasn't able to put all of them together and make it click. You hepled me do that. Thanks a lot!!
It’s truly amazing getting that ‘click.’ It’s what allows me to build upon the basics. See my comment a few above…
Very good explanation. You have clarified quite a lot my understanding of optics, thanks!!
You have simplified such a complex topic amazing
I recently found your channel and subscribed, I'm excited to see where it goes and how it grows
I can't imagine a much better video on this topic than what I just watched! Great explanation and illustrations!
Answered everything I wanted to know about optics of camera lens and human eyes. Explained so many things that textbooks could not. Thank you!
I must pause and say, bravo sir. This is delightful, thank you.
You should cover every basic science topic. You made it sound so easy to understand. You should start a basic educational video series about science,i would pay for it! Thanks for the video!!
This is the best video on cameras i have ever seen, thank you!
I’m 53. I wish I had seen this when I was 15 during my first physics class, if for no other reason than to grasp why images can be inverted. The use of animation to help reinforce a concept, along with this brilliant description of the concept, is astounding to me.
Using this as an example, if I don’t get a fundamental understanding of optical inversion, I’ll end up with 38 years of difficulty with geometric optics. But if/when I get a grasp of the basics at an almost intuitive level, building upon that knowledge is possible.
Nice work.
Incredible explanation! This video caused a 'click' in my brain and the concepts are much more clearer now for me.
I absolutely love these videos! Optics and signals are incredibly interesting! Also, I wasn’t expecting to hear the famous Tico Tico!
So well explained! Thanks a lot!
amazing video and very well explained. thank you!
Great video. Would love to see a video on nonlinear optical processes (e.g., supercontinuum generation).
Thanks, I am hoping to get around to more advanced optics topics in due time, but one of the first I am planning to cover is x-ray optics since I have some experience in the field.
@@ImprobableMatter Agree! (working on Photonic Crystal Fibers and supercontinuum generation here, can help if needed)
Totally ;)! Let's talk about Photonic Crystal Fibers while he is at it!
@@ImprobableMatter definitely looking forward to that! I use XRD in my research and generally interested in x-ray scattering and spectroscopy. Curious to see what you discuss in your video.
@@ImprobableMatter Great! I'd love to see a video about both of these topics.
Great explanation! It helped me a lot!
Excellent explanations!
Very informative. Thank you.
Hmmm...... you have made a dizzing-enigma into the obvious, Well-Done.
this man knows everything
very clear! thank you for what you do!
Hello!
First off - major thanks for the videos you are posting. They are just about the best I’ve ever seen on the topics you discuss!
I have a question: What software are you using to create your graphics?
Thanks. I am using InkScape, which is a free and open source vector graphics editor.
@@ImprobableMatter Thank you for the reply!
This was great, thank you loads!
I love these videos!
Your early videos are confusing. Your later videos are insanely engaging
I look forward to see wtf you're going to do with this
Thanks, that's why it's called Improbable Matter. :)
this video was on fire!
Me encantó cada segundo, resumiste años de mis estudios de optica, me encantó.
Very good video make more like this pls ❤
amazing video
thank u ashens
I loved this
What I find amazing is lenses evolved in nature to the level of sharpness we and other mammals and birds can see.
Superb.
Superb
helps explain why close objects like roses in our garden are blurry and apartment buildings several miles away are crystal clear!
Awesome, do more educational videos, you are on fire
10/10
thanks:)
The reason why in your everyday life you don't notice things becoming blurry in the distance is because your brain tricks you in a few ways. Firstly your eye is actually never standing still, it's constantly darting all over to scan your FOV, it's just so fast and the movements are so minor that you don't consciously notice and your brain just sorta edits it out. Secondly your brain will just remember what a place looked like the last time you focused on it and just keep that there, so to you it looks like it's still in focus. Lastly your brain doesn't necessarily need to have your eyes focused on an object to recognize what it is, it's really good at recognizing objects and as such will just reconstruct them even from a blurry image and make it look sharp to you. This however is also the basis of most visual illusions and is why you often have the experience of thinking you saw something out of the corner of your eye only to look and see it's something totally different, especially when you think you see someone. Your brain is especially biased towards recognizing humans and especially faces and as such will often wrongly see them and insert them into places where they aren't.
The fact that we experience the world as basically unconstrained by the limits of optics, unless you use glasses, has also presented a huge issue for movie makers. Cameras of course can't do any of these things and when we watch a movie we just see it on a 2D plane were we don't need to bother focusing at all. For a long time therefore movie makers did everything to avoid having visible blur because it looked unnatural or were very careful about making the audience not notice it, early on in the history of cinema it also tended to be the goal to avoid calling attention to the fact that someone was watching a movie. Later on however that taboo was broken and movie makers started using focus and blur as an active tool, it's fairly common for example to focus on an object in the foreground to only later reveal the background when something happens in it. This also lead to media which never had this issue in the first place to reverse engineer the effect, animation and games of course never had to deal with focus since the scene is rendered as a 2D image, but methods to replicate the action of a lens were found in order to utilize similar effects.
This was great. I find it interesting to zoom in on a jpeg of an aircraft. I really , really like airplanes and have trained myself to recognize a lot of them from most angles, even when the image is only of a small part of the entire craft - much like your description of humans being able to easily recognize faces.
Anyway, what I find interesting is after zooming in until the image is so pixelated it’s not recognizable, I’ll zoom back out until my brain recognizes the airplane. Then my brain somehow replaces the poor quality image from that’s in my memory, and my recollection of the airplane will be clear and in the orientation of it in the image.
Nice 👍🏾
Great video. Which software did you use to do the animations?
Inkscape.
Whatever your undertaking may be, good optics are paramount.
Never seen the example with the mudy road and the car
Perfect analogy though
Great video, I learned a bit. Im still fuzzy on what the aperture’s actual function is in a modern camera. Does it serve the same function as an adjustable pinhole box? I just feel like the function has to be different when lenses are in play.
First of all, your camera has to have some size of aperture - it can't be infinitely big or infinitely small. The reason to adjust the size of an aperture on a modern camera (it has lenses to focus the light, no need to use the pinhole effect) is to adjust how much light is getting in and therefore how bright the image is. If the image is too bright, it might saturate and everything becomes washed out. If the image is too dark, you can't see anything.
For some reason I feel like im missing some simple stupid principle that I cant wrap my brain around. So I appreciate the explanations. I do get that the aperture blocks light and how it affects shutter speed and all that. However it somehow affects focal length right? because then you widen the aperture, you get that blurry effect behind your subject, basically you narrow your “in focus” range.
You're not wrong to be confused, there is something I didn't get to in this video called "depth of field". It's not the focal length, but it is to do with what happens to objects that aren't quite in focus. A smaller aperture means things away from the focal point are clearer (but the whole image is dimmer).
fiberoptics would be fascinating to know more about simci it is the very medium this data is sent thru 🤩
Well, only the binary data is sent; actually all kinds of channels are able to be sent through fibre due to its incredible capacity for bandwidth. It’s only after a computer reassembles this binary data and decodes it into an image…or text, or video, or etc….that you’ll see on the display.
Fibre optics use optical laws to transfer data, but it’s still just a type of medium for data transfer - just like a wired or wireless connection also passes digital data.
Please tell me what dictates the resolving precision of a mirror or lens and why.
The resolution is determined by how precisely the optic is shaped, by the wavelength of the light, among other things.
@@ImprobableMatterThanks for the reply. I've also recently been informed that though parabolic mirrors would be excellent since they do not suffer form spherical aberation they would be far more difficult to shape accurately enough for visible light.
Question:
If in a telescope I have two eyepieces with different focal lengths. One has 20mm focal length while another is at 10mm, with the 10mm supposedly producing greater magnification but with a narrower field of field. The trouble is I don’t know why it is like that- why does the 10mm focal length produce greater magnification but is limited to a narrower field of view. I would assume it’s to do with the shape of the lens having more curvature and thus refracting power, but I don’t know how this links in with seeing a larger image. Any help is appreciated. Thanks.
I would have thought it would be the other way around, like here: www.edmundoptics.co.uk/knowledge-center/application-notes/imaging/understanding-focal-length-and-field-of-view/
@@ImprobableMatter I don’t know if it’s anything to do with it being a telescope and not a camera ? I have a physics book that says the opposite to my telescope manual but it’s talking about a camera in the book🤷🏼♂️
@@townley1017Might be another aspect of the design. What are the different lenses are like, physically?
@@ImprobableMatter I’ll have a look. The book I’ve got is very thorough so I should find my answer in there. I’ll report back once I’ve figured it out.
Great video! I just have a question that I can't quite comprehend. Imagine I have a telescope which consists of two convex lenses, and I'm trying to image the moon. Since the moon is basically at "infinite distance" (relatively to the objective, i.e. the lens closest to the moon), a real image of the moon is created at the focal length of the objective. Firstly, I don't understand how big this image actually is, since the magnification formula says that M=-d_i/d_o, and d_o is huge (the distance of the moon) while d_i is equal to f (say 200mm). So the magnification should be an extremely number, right?. Then, a second lens is used to create a second image of this first image. Lastly, my eyeball effectively acts as another lens and can look at this second image after the eyepiece and supposedly it should appear enlarged. Why does the image appear enlarged? Have I made some wrong assumptions? Thank you!
Have a look at an example like this: www.livephysics.com/problems-and-answers/optics/lens-system-image-distance-magnification/
For the moon, you might as well set the distance to the object to infinity. The magnification applies if you put a digital camera detector (CCD) at the final image plane. Just imagine your entire eye is the same as the detector (you can consider another system with a third lens if you like, but you'll get the same answer).
How is the size of the focal plane determined?
In principle, it can be as large as you like. In reality, it's to do with how big your optic is, how big your detector is, the housing and so on.
Great Video. There is just one thing at 3:45 that could lead to missunderstandings. The squash ball loses some energy when it touches the wall, so the angle of exit is different to the angle of entry.
Everyone says the brain naturally compensates the inverted image, but what if it doesn't? What if everything is really upside down and we just think it is right side up? We could be walking on ceilings without even realizing it. What if things really fall up but we think they fall down since the image inverted on our eye?
My brain took this question and ran with it.
It ran hard, but maybe not very far.
Does it even matter which way up we see the world?
If "up" is the direction away from the planet, and "down" is towards it, flipping our vision doesn't affect anything.
However, that doesn't take self-relative positioning* into account- wait...
I might just be too tired to wrap my mind around it, but would *that* even make a difference? I... Yeah, definitely too tired to figure this out**, or even properly finish that thought.
What I was getting at is approximately: "What effect would vertically but not horizontally mirroring your vision even have? Is it possible for your brain not 'not compensate', or is it an innate part of correlating vision with your surroundings?".
I hope something interesting can be extracted from this dubiously coherent comment :]
I thought I'd finished this comment, but apparently not. I've thought of another, seemingly better way to word the question that is my contribution to your question:
"If someone had their vision flipped vertically for their entire life and was used to it, what effective difference would there be compared to someone who's vision was not?"
* I don't think it's called that, but hey.
** He says, before describing his question in a more succinct manner, twice.
Kind of as silly as flat earth theory
@@leobracken2316 Basically, the problem arises when we draw a diagram on paper, assuming the world is 'right-side up,' but then the lens flips that image onto the retina, which is 'upside down' to how we see things.
So we say, "The brain flips this image to make it match!!!"
But here is the error! If the brain 'flips' the image, then we must un-flip it by drawing the initial object 'upside down.' Thus, the lens will flip this image, making a right-side up image appear on our retinas.
But now the image appears right-side up on our retina, which matches what we see! And it requires no brain programing to 'flip.'
That is, the notion of the brain magically flipping the image is absurd, because it literally does not matter either way, so why would the brain 'evolve' this useless feature to 'flip' images.'
So, in actuality, the entire world and existence itself, is totally flipped with respect to how we view the world; the fact down is defined 'towards the center of Earth' means that image flipping has no effect, because up and down are maintained no matter what.
@@Fireneedsair There is no such thing as a flat Earth theory; there are a few different flat Earth hypothesis, and some of them are quite clever, whilst others of them are quite nonsensical... to the point of outright brain sludge.
@@pyropulseIXXI whatever dude u want to call it. As silly as the what if of proposing our reality is inverted. Lol
Certo então só r viu se fala alguma novidade sobre as roupas e é só
How about vision?
Optical fibers are missing sadly!
2:20 wait, so everything's upside down and my brain lies to me all the time...?
Always has been.
Please make a video on how the camera of a U2 spy plane film objects while traveling over 70 000 feet above the surface
The colour brown 8-)
Fé no nosso país de um beijo e o almoço de ontem foi muito boa noite e é o almoço de ontem e o cafezinho da tarde
🙏🌹🇮🇳 PSSPPP 🇮🇳 PALOJU JAI SRIRAM 🇮🇳🌹🙏
T amo muito muito sucesso sempre felicidades e muitas alegrias para você também e o almoço amanhã de manhã e o cafezinho tava no forno e é só r o almoço de ontem e o almoço amanhã de manhã r da manhã e a noite toda hora ri muito forte mas se encontra
Fala alguma é só no centro da cidade de um e e o almoço amanhã às três dias quando chegar no trabalho da empresa de trabalho e o almoço de ontem foi embora e é só no centro
Gr CV para todos os momentos da vida da vida de vcs e de e o cafezinho tava no centro da igreja
D fui no
nice work, you could continue with the story by talking about the 4k (and beyond) myth, where ppl think their camera can record 4k+ resolution but the lens is already restricted to 2k and they are only generating data rubbish ;-)
What makes you think the lens (even the el cheapo entry level 18-600 paperweights) are resolution limited to only 2000 line pairs on the longer side of the picture?
@@sashimanu you can measure the resolution
Ch e é só centro de São Paulo e é só no é no centro de um beijo e é só no é só no centro é só no é o almoço amanhã e te falo se eu for lá buscar no centro de São Paulo e é só r o almoço
F e o almoço amanhã às noite eu te mando msg de manhã e o cafezinho tava precisando de alguma coisa ER no grupo de manhã r da manhã e o cafezinho da tarde para todos vcs vão vir aqui
Fala comigo no grupo da família e é o almoço de hoje e é só no centro de um beijo e é só r o almoço de hoje né se fala alguma novidade da vida de vcs e de e é
The THumbnail looks like a string instrument, like a banjo or smth.
C a tarde toda vez por favor te amo tanto o almoço amanhã de manhã e a gente vê o valor de cada vez no centro de São Paulo e é o almoço de ontem e é o cafezinho da manhã e a gente se encontra lá no grupo de manhã r viu se fala é só r viu o
Fé e é o almoço amanhã de manhã r da um beijo no coração e o almoço amanhã de um pedido para mim ir no mercado e o cafezinho tava precisando de alguma coisa de mim ER r viu se fala comigo no grupo de manhã e o almoço de hoje
Y a noite toda ET de t e é só r o almoço de hoje né a gente se fala alguma novidade sobre as crianças e o almoço de ontem foi muito difícil é r é é é r é o cafezinho da manhã de manhã r da um jeito r e a
G Du ei ele é só r o cafezinho tava precisando muito muito muito muito sucesso sempre vcs vão vir embora agora a noite a todos da família e o cafezinho tava no forno e o cafezinho da tarde para você e a gente se encontra no shopping hj é só no centro de um beijo e o almoço de hoje e é o cafezinho tava precisando muito de um pedido de um pedido de
D fui lá no grupo da escola da e e é só no é só no é o cafezinho da manhã e a noite a gente vê o valor de cada um pedido para todos vcs estão fazendo as coisas por ai sim entendi agora eu tô aqui no hospital agora da é r é o cafezinho tava é o é só no é só no é
F da vida da e é é é é o errrre rret de todos vcs vão ficar e é só r o cafezinho e o almoço de ontem e o almoço amanhã de manhã e a gente
F e é só no é só no é só no é o almoço amanhã de manhã e a noite a gente vê se encontra lá ER no grupo de manhã e a noite toda vez por causa de mim ir lá buscar
G o cafezinho tava no forno e é só r viu o almoço de ontem e o almoço de ontem foi embora e é só r viu se encontra no shopping né amiga e é só no centro de um e e o almoço de hoje e é só r o almoço amanhã de manhã e
C BB GG GG e o almoço de hoje né se encontra lá no grupo da escola da tia Maria e a gente se fala e é só no é só no centro da igreja de um beijo e é só r viu o almoço de ontem foi
Gr de manhã r da um jeito r e o almoço amanhã de manhã r da manhã de um jeito de ir no mercado e é o cafezinho da manhã de manhã r da manhã de um beijo e é só r o almoço amanhã de um beijo no coração de Deus no comando e o cafezinho da manhã e o
G Du ND no celular da tua irmã e é só r o cafezinho e é só no é só r o almoço de ontem foi embora amanhã de manhã e a gente vê
Du ND no celular g Du ND de e é só r viu se encontra lá ER hoje e é o almoço de hoje né a gente vê o cafezinho da tarde para todos os dias de natal de natal de natal de natal de natal de natal de natal de um beijo no rosto e é só no centro
Yikes🎉
“How optics work”… so, optics is plural?
You can have a single optic, yes.
… what would be a couple of examples of the single optic? Thanks in advance!
@@nowsc "You can learn about a new type of optic for spacecraft in the video linked at the end."
You’ve the God given gift of evolution of an optic nerve.
@@ronjon7942 I’m not religious. Please leave religion out of it when you’re telling me things. Kindest regards.
You do not have scientific honesty in transmission. The word camera comes from the Arabic word قمرة, and the Arab scientist Ibn al-Haytham (965-1038), was the first to explain how to see and reverse the image
Great lesson in the basics of geometric optics, but can you explain how a holographic image is captured and why EUV lithographic masks look like holograms?