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0answers
14 views

What is the minimum required length of mirror to view full object if the mirror is convex?

i want to find the Radius of curvature of a convex mirror. i have all the factors to calculate except for image height of an object and image distane. so i can find the image height of an object from ...
0
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1answer
19 views

Double slit experiment collimating lens?

In some appratus for the Young's double slit experiment a collimating lens is used infront of the double slits, meaning plane wavefronts hit the double slits. But why do we need/want plane wavefronts ...
0
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1answer
33 views

How many foci does a converging or diverging lens have?

I thought this was a simple question but can't seem to find a direct answer. In ray diagrams with a converging or diverging lens, we always draw F (the focal length) on both sides of the lens. But ...
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0answers
17 views

Are there concave fresnel lens production [on hold]

I wonder why most fresnel lens is focused convex lens. Are there any usage and production of concave fresnel lens?
1
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1answer
46 views

Optics problem: Determining the new focal length when changing from film to CCD detector [closed]

An older camera has a lens with a focal length of 50mm and uses 34-mm-wide film to record its images. Using this camera, a photographer takes a picture of the Golden Gate Bridge that completely ...
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1answer
26 views

Ray diagram for refraction

I'm having trouble finding out any errors in a ray diagram. The question is as follows: A ray of light falls normally on the curved face of a semi-circular plastic block, it hits the horizontal ...
4
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1answer
53 views

Options to correct rectangular laser beam profile?

We recently switched to a 405 nm laser diode which has a terrible beam profile -- it is a well-defined rectangle with an aspect ratio of about 10:1. The image below shows the collimated beam which ...
1
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1answer
52 views

Lens with a mirrored coating [closed]

A biconvex lens of refractive index $n$ and radius of curvature $r$ and focal length $f$ floats horizontally on liquid mercury such that its lower surface is effectively a spherical mirror. A point ...
0
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1answer
24 views

What is the formula for determine heating produce by a lens? [duplicate]

When I put a lens along the the sun it convert the sun energy to heat and maybe fire the substance beyond the lens. How could I determine the heat produced and what is the formula?
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2answers
405 views

How do I find the right lens for my laser?

I purchased this line laser recently and I'm running into a bit of an issue. The laser shoots out at a 120 degree angle which is perfect. However, once the laser spreads to about 4.25 inches, I need ...
3
votes
2answers
43 views

Arrow that changes direction home experiment

I saw this cool optical effect in a experiment on Youtube: https://www.youtube.com/watch?v=G303o8pJzls Could anyone explain to me why the arrow points in the opposite direction? I have read ...
0
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0answers
45 views

Is there a way to cancel lens effects?

If I had 2 identical lenses, and put the two facing each other in oposite directions, would their effects be cancelled? Is there a way it could be done, maybe with fresnel lenses, so that it would ...
5
votes
2answers
1k views

Can spectacles converge sunlight to an extent that it burns the eyeball?

I need to know whether wearing spectacles can cause optical harm. I saw a movie where one pair of glasses was placed on table exposed to sunlight, then the sunlight converged and focused to a point ...
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2answers
62 views

how to trace light after refraction by a camera lens?

I am a programmer and I am doing a camera simulation, I am stuck in a matter of how to know where arrives every ray of light after traveling through the lens and being refracted. Every point of the ...
3
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0answers
29 views

What does it mean for a Fresnel lens to have two finite conjugates?

I'm in a situation where I need to reverse engineer a product that my company already manufactures and sells, but it wasdesigned too long ago for anyone to remember. It uses a Fresnel lens with the ...
-1
votes
1answer
99 views

Ways to measure the focal length of a convex lens with only natural sun light [closed]

What are the common ways to measure the focal length of a convex lens with only natural sun light?
0
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1answer
56 views

Fresnel lens/kinoform: How to model diffraction at the edges of zones?

I would like to find the intensity distribution of light due to the diffraction at the edges of zones on Fresnel lenses or kinoforms. (That is, location of orders, heights of maxima, etc.) I can't ...
1
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0answers
27 views

How to choose a type of a lens for a particular optical component?

With almost no experience in optics, I am trying to create a system that looks something like that: The idea is to be able to focus the parallel wide beam (shown in broken line between lens 214 and ...
0
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2answers
34 views

Photographic lenses from the physics point of view

First of all, we need to define the term lens for the question to be totally clear and accurate. A camera lens (also known as photographic lens) is an optical lens or assembly of lenses. [Source] ...
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1answer
40 views

Lens surrounded by two different materials?

If have a material refractive index $n_1$ then a lens refractive index $n_2$ then another material on the other side of the lens (but in contract with the lens) refractive index $n_3$. How do I find ...
0
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1answer
60 views

System of Lenses. Virtual Objects and Nature of Image (Real/Virtual)

We have a certain system of lenses: Lens 1: Focal length: 19.5 cm Lens 2: Focal length : 9.5 cm I put an object 36 cm away from lens 1. Then, I put lens 2 between lens 1 and a screen. The separation ...
2
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1answer
171 views

Converging Lenses with Objects at “Infinity”

Whenever we take the case of an object at infinity, we say that the image formed ends up being a point of light on the focal point if we had put a screen right at the focal point. Now, for my lab, ...
1
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1answer
108 views

Issue on sign convention with optics

I have a problem understanding the sign conventions used in the equations that describe the imaging properties of mirrors - in particular, when and why should I use a positive or negative number for ...
0
votes
2answers
66 views

How to chose right lens for concentrating IR signal? [closed]

I am looking for the right acrylic lens. Since will be buying at least 1000 pieces I don't want to make any mistake. I want to concentrate the signal from IR LED in a 1cm diameter tube at one point ...
1
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1answer
72 views

How does a non-diffracting beam form from a converging ring of illumination?

I am trying to intuitively understand the basics of the supplementary text of a recent publication from Eric Betzig's group on lattice light sheet microscopy (1). I am confused by the explanation of ...
3
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0answers
15 views

Colour of artifacts in a lens flare

I'm adding a lens flare to an illustration; which got me thinking: Are the colours of the artifacts (hexagonal/circular) which appear in a lens flares purely random, or much like a rainbow ...
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2answers
261 views

How to Ray Trace Chief and Marginal Rays in Thin Lens Systems

Looking at the below images, the chief and marginal ray appear to be modeled just fine. But, those lines don't seem to conform to the rules typically used in thin lens ray traces. An example of ...
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1answer
79 views

Refraction through converging lens: finding image distance and image height

So in this situation there is a 1.79 meter tall person standing 30 meters from a 150 mm converging lens and I'm trying to find where the image will form and how tall it will be. My problem is in ...
2
votes
1answer
140 views

Keplerian Telescope Exit Pupil Location - Whats the Basis for It's Formula?

For a simple two lens Keplerian telescope, this is the formula for the location of the exit pupil: $$z'=\frac{f_2}{f_1}(f_1+f_2)$$ Where $z'$ is the distance to the exit pupil location (i.e. eye ...
1
vote
1answer
314 views

How does 1/f come out as the intercept when plotting a graph of 1/u and 1/v in convex lens?

On this link, in the convex lens second method to calculate focal length. I did not understand how the graph of 1/u and 1/v can give 1/f as the intercept? Could someone please explain?
1
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0answers
19 views

Ellipsometry measurments

Why it is good to measure on a wavelength range in ellipsometry instead of using a single wavelength. I understand this that the measured data (ψ and ∆ ) plotted against wavelength and if we have ...
0
votes
1answer
47 views

Broken Thin Lens Algorithm [closed]

We all know the thin lens equation. For $o$ being a horizontal object distance and $f$ being the focal length, the horizontal image distance $i$ is described by: $$\frac{1}{f} = \frac{1}{o} + ...
2
votes
3answers
59 views

What defines camera's size?

Smartphone camera is small while others are big. I know some functions like zoom can change physical size and multi lens,.. etc So, assume that a without zoom, what define camera lens? I want to get ...
1
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0answers
53 views

Angular magnification of a two-lens system

Suppose an object is a distance $d_o$ from a first lens (which has a focal length $f_1$), where $d_o>f_1$. Behind the first lens is a second lens with a focal length $f_2$, such as to produce a ...
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0answers
42 views

Lens parameters / Principal Planes vs. Entrance and Exit Pupil

Under what conditions are the Principal Planes not the entrance and exit pupil? For the definition of Principal Planes see: http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/priplan.html ...
2
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2answers
60 views

WHY is a Refracting telescope image distance $S'=-\infty$?

In the above slide, it says that "Eyepiece '2' makes the image distance $S'$ approach $-\infty$." However, What I don't understand is that if I place my eye right at the Eyepiece 2, then I would see ...
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2answers
918 views

How to calculate magnification

I have various magnifying glasses and I'm using them when I take macro photos with a phone or a camera. I want to group/label my magnifying glasses by their magnification power. And by magnification ...
1
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0answers
23 views

Optics - Derivation of Linear Magnification of Lens without Sign Convention [duplicate]

In some posts in this forum I've read that sign convention in optics is useful for making formula memorizing easier, and that we have to use sign convention again while applying the formulae to ...
2
votes
3answers
66 views

In an optical system with a single convex lens, where should the image area be placed in order to take pictures at infinite focus?

I'm trying to learn how camera lenses work, and have gotten stuck. Say that we have an optical system consisting of a single lens with focal length f, and we want to take pictures of objects which are ...
1
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1answer
55 views

Is a lens with a focal point that doesn't shift as sun shines from different angles possible? [closed]

My question: Is it possible to manufacture a lens whose focal point doesn't shift in any direction during the day when the sun shines from different angles? It is understood that the focused energy ...
0
votes
3answers
215 views

Image formation (lenses) [closed]

I have a question regarding image formation by lenses. It is the following: A lense with a focal length of $-48.0cm$ forms an image $17.0cm$ to the right of the lense. Where is the object positioned? ...
0
votes
1answer
147 views

An optical system with image from a convex lens forming behind a concave lens

I am having a problem drawing optical ray lines for optical systems. Namely, one which have a formation of image of the first lens beyond the second lens. Take the picture below as an example: In ...
1
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1answer
241 views

Creating large aspheric lens profile for CNC cutting out of Acrylic plastic for huge Camera Obscura

I plan to use a CNC mill to cut a plano-convex aspheric lens from a large (300mm dia) thick(30mm) block of Acrylic (PMMA/Plexiglass). I need a focal length on the order of 800-2000mm The purpose of ...
3
votes
2answers
184 views

Interference at the focus of a convex lens or a concave mirror

Now consider parallel rays travelling towards the convex lens. After emerging they get converged at the focus. Won't this lead to interference between light rays? Practically it should but I would ...
4
votes
1answer
823 views

Sign convention for mirror and lens formulas

I have just started learning optics at school and my teacher derived the lens and mirror formulas. While doing so, she applied the sign convention for $u$, $v$ and $f$ and arrived at the final ...
0
votes
1answer
105 views

New focal point of converging light through a concave lens

Suppose I pass rays of already converging light through a concave lens. The rays are equally centered on the lens such that the original focal point is through the lens and centered on the lens axis. ...
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1answer
62 views

How should we put two lens?

How should we put two converging lens in order for parallel rays passing between both lens to remain parallel?
3
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1answer
113 views

Help calculating field of view for ball lens I just bought

I have a 5 mm (diameter) solid ball lens that I intend to place in front of a 36mm X 24mm camera sensor (I have already made preparations for the image to be focused and for the sensor to not be ...
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3answers
2k views

What happens to the index of refraction of a lens if placed in water?

What happens to the index of refraction and focal length of a lens that is initially in air that is then placed in water?
3
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2answers
100 views

Plano-convex lenses

When the spherical side of a planoconvex lens is towards the source we will see reduced aberrations normally we use it for the beam collimation. When we use two planoconvex lenses configuration why we ...