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7
votes
5answers
248 views

What causes blurriness in an optical system?

The way I understand the purpose of a typical optical system is that it creates a one to one mapping between each possible incident ray and a point on a sensor plane. This is like a mathematical ...
2
votes
2answers
108 views

How to produce a loss-free combination of two “identical” beams?

This is for anyone with experience in optics/imaging/photography as well as anyone who likes to puzzle over tricky physics problems. As the title suggests, this is about combining two (for all ...
3
votes
2answers
207 views

Diffraction by a lens

The fraunhoffer treatment of circular apertures yields a diffraction pattern of circles, with the first minimum (dark ring) at an angular radius of $\theta$ where $\sin(\theta)=1.22\lambda/b$, where ...
0
votes
2answers
112 views

Designing a Handheld Optical Communication Device

I'm in a group trying to design an underwater optical communication system for a capstone project. For this system we are planning on using multiple high powered LEDs passing through a lens system, ...
0
votes
1answer
201 views

Image formed in a compound light microscope

I am trying to understand whether the image formed in a compound light microscope is at infinity or not. I get conflicting answers everywhere I look.
1
vote
1answer
476 views

how does the mirror equation works and what lead to using of sign convention?

EVERYTHING HERE IS FOR CONCAVE MIRROR Everywhere I see the derivation of the mirror equation is given by placing an object before the focus and then proving similarity of the triangles to get to the ...
0
votes
1answer
87 views

virtual boxes mirror reflection

The problem statement Find the lightpath with a given starting and ending points via one or more mirrors. In those kind of problems you try image someone pointing a laser with a very narrow beam ...
1
vote
0answers
224 views

How would you make 360 degree vision glasses? [closed]

Animals that have an eye on each side of their head have 360 degree vision so just like with the inverted vision glasses you can buy I'm wondering how you make 360 degre e glasses? I'm thinking of a ...
5
votes
8answers
544 views

Is there a lens that would invert my vision?

Would I be able to invert my vision by mounting a particular lens in front of each eye? I am currently able to achieve this by mounting a right-angled triangular prism across both eyes. The specific ...
4
votes
4answers
225 views

Thin lens formula

Can someone help me or guide me how the thin lens formula: $$\frac{1}{s_1}+\frac{1}{s_0}=\frac{1}{f}$$ can be proven? I was trying to prove it on my own using similar triangles, only to fail.
2
votes
2answers
946 views

Why does aperture size affect depth of field in photography?

Why do small and big holes (the aperture) in a lens change the depth of field in the image? (if you have big hole you have smaller depth of field). I wondered if I should ask this on ...
0
votes
1answer
76 views

Creating small polarised scientific lenses?

How would I go about creating small polarised scientific lenses? Thinking 5mm by 5mm, with a light-source behind it for the purposes of reducing (polarised) surface reflection (assisted with a ...
1
vote
0answers
145 views

Lenses and Magnification [closed]

A $2.05\text{ cm}$ tall object is placed $30.0 \text{ cm}$ to the left of a converging lens with a focal length $f_1 = 21.0\text{ cm}$ . A diverging lens, with a focal length $f_2 = -42.5\text{ cm}$ , ...
5
votes
5answers
525 views

do lenses with curved focal planes exist

I know about spherical, aspherical, cylindrical lenses, but are there lenses that could have a curved focal plane? for example, the retina of the eye is curved, and still we see sharp images of ...
12
votes
6answers
7k views

Are Fresnel lenses widely used for solar electricity? If not, why not?

I was just wondering why Fresnel Lenses are not widely used in the production of solar electricity. Their use there would mean that you could produce heat within a fraction of a second, up to a few ...
1
vote
2answers
140 views

Good explanation of a real image?

Okay well I've started to study phys chem in school recently and I honestly can't get my head around what a real image actually is I've asked my teacher to demonstrated it but she's quite lazy, and ...
0
votes
0answers
212 views

Cylindrical lens aberration fixed by roll

I have two cylindrical lenses essentially forming a beam expander. The problem that I am having is that I am seeing a very strange aberration. The image becomes "squashed". Cylindrical lenses only ...
2
votes
2answers
1k views

Why do powers of lenses get added?

In our physics class, we were told that a power of a lens is defined as the reciprocal of its focal length. Also, the powers of multiple lenses get added up. But I didn't understand why this is. I ...
1
vote
1answer
840 views

Magnifying factors of multiple lenses (closely packed)

Well the following question I really struggle to find an answer A thin lens creates an image of an object with magnification -3. A second identical lens is positioned very close to the first ...
25
votes
4answers
4k views

Why does wet skin sunburn faster?

There is a popular belief that wet skin burns or tans faster. However, I've never heard a believable explanation of why this happens. The best explanation I've heard is that the water droplets on the ...
16
votes
5answers
3k views

Why do nearsighted people see better with their glasses *rotated*?

If you are nearsighted (like me), you may have noticed that if you tilt your glasses, you can see distant objects more clear than with normally-positioned glasses. If you already see completely clear, ...
1
vote
0answers
102 views

Range Finder Question - Optical Filter For An Apd [closed]

I am working in a range finder project. I have encountered a problem with an Avalanche Photodiode. I am trying to use a pulsed laser on 980 nm(infrared) but I receive a lot of noise from the APD. I ...
-1
votes
1answer
51 views

Magnification, and it's application [closed]

I'm having a problem with a very trivial thing- magnification makes things bigger. But if it doubles or triples the size AND distance away, why does it even help? I think I'm just ignoring something ...
3
votes
1answer
874 views

Calculating minimum object distance for a lens

I am trying to figure out the Minimum Object Distance based on a simulation available here. In case you can't open it (it's a Java applet...) I'll describe it briefly. It shows an object emitting ...
1
vote
2answers
114 views

Simulating an Optical Lens

An optical lens focuses the light according to a rule (due to its special shape) and we know that rule. Now, instead of making bigger and bigger lenses, can we use an array of optical sensors and the ...
1
vote
1answer
201 views

Effect of slits and a lens

We have a screen with two slits (Young style) separated by a distance $d$, one of them receives a planar wave of $600nm$, the other receives a planar wave of $400nm$. Behind the slits there's a screen ...
1
vote
0answers
70 views

Hows lensmaker formula works? if Radius is zero?

I am doing my revision and there's such a question. However, when I tried to plug the values into the lensmaker formula, I find that one of the R is equal to zero, as it is not curved. $(n_2 ...
2
votes
2answers
110 views

What is “field size” when referring to perspective?

I'm trying to get my head around perspective. If you look at the animation in Wikipedia : You can see that the cube looks very distorted, then the edges go more parallel. From my understanding, ...
3
votes
2answers
1k views

How to draw a ray diagram from focal length, object and image heights?

Q. An object of height 8 cm is placed in front of a lens. It's inverted image of height 4.8 cm is formed on the screen. If the focal length of the lens is 12 cm then by drawing at scale calculate the ...
1
vote
1answer
1k views

Calculate the distance between two points from iPhone Camera

I want to calculate the distance between two objects using an iPhone camera. Suppose I'm standing with my iPhone 10 feet away from the objects. Now, I want to calculate the distance between those ...
1
vote
2answers
193 views

Convergence of Light on the Retina

So, I've learned about lens ray diagrams-but the problem I'm having is that when ray diagrams are drawn for a point of an image, they converge to another point, but there are two problems that I see ...
4
votes
1answer
134 views

Optics, lenses and our eyes

When we view an image, is the focal point of our eye on our retina? Shouldn't that hurt? Also, if that is how our eye works, then why don't lenses put the focal point their equivalent retina? I was ...
0
votes
3answers
775 views

Paraxial rays and marginal rays question

Paraxial rays are found to focus far away the lens whereas marginal rays focus near to the lens, why? I didn't find satisfactory answer in my academic book..
3
votes
1answer
1k views

Why do focal lengths affect magnification?

For compound lenses, the image formed by first lens acts as the imaginaryobject for the second lens. In telescopes, the objective lens projects an image on its focal point which works as the object ...
2
votes
1answer
278 views

How to calculate beam spread of a non-point light source via an aspheric lens

I need to determine the angle, or rate of divergence of light from a single aspheric lens when I place a non-point light source (e.g. LED array) at a given distance from the lens which is less than ...
1
vote
2answers
492 views

How does the eye perceive a real image?

Okay, so I'm trying to grasp how the human eye will perceive the real image created for example by a convex lens. Take the upper image in this picture for example. If you were to place a screen at ...
0
votes
1answer
4k views

Magnifying Glass-How does it work? [duplicate]

How does a magnifying glass work? I know it creates a virtual image of the observed object but how is it possible that humans can see the virtual image?
3
votes
2answers
179 views

Proof that a spherical lens is stigmatic

In geometric optics, we generally allow that, for example in the case of a convex lens, rays coming from a particular point get refracted towards another particular point on the opposite side of the ...
0
votes
0answers
1k views

Why a person with a further near point experience a larger magnification with a magnifier

Two people, Micah and Lyra, with different near points are equally close to an object. Both inspect the object through the same magnifier by holding the lens close to the eye. Micah's near ...
1
vote
1answer
326 views

What determines the sign of an image distance?

A lens placed at the origin with its axis pointing along the x axis produces a real inverted image at $x = - 24 cm$ that is twice as tall as the object. What is the image distance? Why ...
5
votes
2answers
155 views

Smaller Airy disk with another lens?

Is it possible to reduce the airy disk size produced by one lens with another lens placed after the previous one? For example, parallel ray incident on first lens L1 (without aberration), then there ...
0
votes
1answer
617 views

calculating focal length of meniscus lens

As I read about telescope, distance between objective lens and eyepiece must be equal to addition of their focal lengths. D = F1 + F2 I used one of the eyepiece ...
4
votes
1answer
194 views

On the optics of high-resolution surveillance drones

In this youtube video (which is an except from a documentation I believe) a DARPA development for a high-resolution surveillance camera is presented. This question is regarding the optics that are ...
9
votes
3answers
500 views

Put a sensor at the focal length, behind, or in front?

My intuition tell me that at the focal length a convex lens all the light converges to a point. Following that logic, it would make sense to me that a camera chip would either need to go slightly in ...
1
vote
2answers
203 views

Ideal distance of eye from a lens

I observed that when I keep constant distance between object and lens but I move my eye, I get different magnification. When I am closer to lens I can see large image of the object. But if I go away ...
1
vote
2answers
287 views

Is it possible to enlarge the output angle of a projector with outside lens?

I have a very small projector, with a small output angle (30 degree). In my current demand I want a bigger output angle(90 degree), so that I can get a bigger image within a given distance. Is it ...
3
votes
2answers
386 views

Effect of gas or liquid within a compound lens system

Hi my question is if a compound lens system if filled with gas or a liquid how does it affect the system when compared to the lens system being separated by air alone. Does this affect the focal power ...
0
votes
1answer
173 views

Image Formation (Convex-Convex lenses)

I'm given with these data: Lens 1 and lens 2 are convex lenses with different focal lengths Distance of object from lens 1: 50 mm Distance between lens 1 and lens 2: 100 mm Distance of final image ...
1
vote
0answers
86 views

How does a lens affect the field of view in a mirror?

If one looks into a mirror, he can see a certain field of view. If he places a convex lens that magnifies (or a concave lens that does the opposite) in front of the mirror, but so that he can still ...
5
votes
1answer
188 views

Optics Paradox?

Imagine we have two lens, one convex and one concave, spaced in such a way that the convex lens is before the concave lens. Now each lens has its own focus length and both are spaced such that the ...