# Questions tagged [lenses]

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40 views

### It is harmful to look directly towards the Sun. Why? [closed]

Sun's electromagnetic spectrum, Convex lens of the eye, Retina.
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### What is the proof that we can use virtual object to know the place of formation of image in case of convex/concave lens?

What is the proof that we can use the location of virtual image in the lens formula to get the location of the image (convex/concave lens)? The following problem might make my question more clear. The ...
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### Focal Length as it relates to Field of View

I understand that in physics, for a converging lens, the focal length is based on the refractive index of the lens material and its curvature. However, I started reading a bunch of photography ...
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### How do fundamentally electrostatic lenses work?

I don't need any super specific answers. But I would it appreciate alot if someone could either confirm or correct my thought process. I know that for many of you this will sound super obvious but for ...
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### Explain the formula of $P =1/f$ for mirrors [duplicate]

Using magnification formula for mirrors $m = f/f-u$. This gives $m$ is linearly proportional to focal length. So, how do we intuitively understand power of a mirror?
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### How does longer length of optical path in binoculars increase its magnifying power?

I just read about Prism Binoculars from my high school physics textbook. However, I am not able to understand how does increasing the distance light travels from the objective lens to eyepiece can ...
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### What's the difference between Electromagnetic lens and an Electrostatic lens?

So I've read a couple of pages and watches a few videos but at their core neither has answered this basic question. I remember from the lecture that the prof. said that one needs a high current while ...
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### Does adding a supplemental lens attachment to a phone increase the megapixels it can resolve?

I am reading: https://en.wikipedia.org/wiki/Optical_resolution But am confused if adding a supplemental lens to an imaging system (in this case my phone) would change the amount of information ...
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### Why do plano-convex lenses reduce spherical aberation?

I keep reading this in comparisons of different kinds of lenses but I don't understand why the flat side would change the amount of spherical aberration if the focal length still has to be the same?
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### Dilemma in calculation of percentage error while measuring focal length on an optical bench

An optical bench has $1.5$ $m$ long scale having four equal divisions in each cm. While measuring the focal length of a convex lens, the lens is kept at $75$ $cm$ mark of the scale and the object pin ...
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### Can microscope lenses be non-spherical?

Most lenses are spherical, but... Are there elliptical, parabolic or hyperbolic microscope lenses? (I asked a similar question, about telescopes, on Astronomy S.E.; I hope this is not considered '...
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### Lens Maker equation and Geometrical equation

or a myopic swimmer with a prescription of -7.0 diopters, what should the radii of curvature of the lens surfaces be if the goggles are made from a high index plastic of n = 1.6? First, what is the ...
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### What determines if light rays will be parallel to each other after refraction through a lens?

This is an example of a refracting telescope: As you can see, when passing through the eyepiece (second lens), the rays are refracted parallel to each other. Why are they refracted parallel relative ...
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### Do progressive lenses consist of plateaus?

Anticipating that in the not-too-distant future progressive lenses are unavoidable, I have inquired at a store from a famed brand (LensCrafters) about the nature of these lenses. There, to explain ...
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### Which path does light take through a lens?

In the picture below, the three principal light rays are drawn refracting through the lens , forming an image on the other side. But which path does the light actually take? That is , if i place my ...
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### My question is about ray optics particularly image defects

I was learning about spherical abberation and in my book it is written that when parallel rays pass through lens marginal rays (which are far from principal axis) are bent more than paraxial rays(...
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### Biconvex lens kept on a plane mirror

Q. A thin biconvex lens is kept on a plane mirror. When an object is kept at $20 cm$ in front of the lens, its image is formed at the same point. The focal length of the convex lens is The solution ...
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### Focus at infinity

I have myopia so I wear corrective lenses. One set of glasses I have is designed to focus from about 2 feet to infinity. I can see the dashboard of a car, but I can also see buildings at long ...
65 views

### Focal length of lens combination [closed]

The adjacent figure shows a thin plano-convex lens of refractive index $μ_1$ and a thin plano-concave lens of refractive index $μ_2$, both having same radius of curvature $R$ of their curved surfaces. ...
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### Validity of wave front curvature calculation for a gaussian beam depending on the focusing conditions

The curvature of a gaussian beam is usually given by $$R(z)=z\left(1+\left(\frac{z_r}{z}\right)^2\right)$$ with $z_r$ the Rayleigh length. Is there a limitation for that curvature (similar to usual ...
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### What shape are digital camera lenses?

I originally thought that digital camera lenses are the same shape as a magnifying glass but I saw that lenses like that are meant for our eye which has a curved detection surface and if a camera used ...
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### Why do we need a lens in the delayed-choice quantum-eraser experiment of Kim?

This is the delayed-choice quantum-eraser experiment of Kim diagram described on Wikipedia https://en.wikipedia.org/wiki/Delayed-choice_quantum_eraser Why do I need a lens in front of the ...
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### Rainbow Colors on a Water Droplet on a Screen

I accidentally fell a water droplet on my mobile phone's screen. But on observing closely I saw that the water droplets showed rainbow colors (the screen was mostly white). By rainbow colors I mean ...
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### Parallelising light rays from a laser projector using planoconvex lens

Materials: 26mm Dia x 35.2mm FL, Grade 1, Plano-Convex Lens. PicoP laser picoprojector. The problem: I've got a question about using a lens to parallelise light rays coming from a laser projector. ...
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### Do the size of the objective lens of a telescope affect the size of the field of view?

According to diagrams like this the answer is no, because every part of the objective lens gives the whole image. But when I cover part of the objective lens of my binocular, I only see part of what I ...
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### How does focal length affect magnification?

My answer would be the longer the focal length, higher the magnification will be, resulting in a larger image. But in a ray diagram, how does it look? I am searching for a comparison of ray diagram ...
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### Finding the Focal Length of a Thick, Plano-Convex Lens

The lens maker's formula takes into account the thickness of a lens. However, if one surface is planar, its focal length should be infinite. But that means that with the below formula, the thickness ...
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### Estimating the focus plane of camera via thin lens equation [closed]

I have a camera that outputs a JSON file for every image taken. In the JSON file, I can find camera-specific and also the photo-specific acquisition parameters used. The issue is I wish to estimate ...
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### Can a person with healthy eye see things clearly if he/she uses spectacles?

Let's first see the mechanism of working of concave lens for correction of myopia. If a myopic eye has a near point less than infinity say 1 meter(m) then we use a concave lens of focal length 1, so ...