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2
votes
1answer
33 views

Why don't eye lenses alter depth perception?

What it is going to do is bend the rays so that light from infinity "appears" as though it is coinciding with a person's far point. In doing so, it allows the person to see a clear image, without ...
0
votes
0answers
39 views

Determining focal length and positions of principal planes [on hold]

I have been stuck on this problem for a few days now, and I am still not confident which approach to take with this question. I am consider using the Gullstrand Equation, but I hear some of my ...
0
votes
0answers
31 views

Sign convention in geometrical optics

This is slight misconception that has bugged me. While deriving the mirror formula: $$\frac{1}{u}+\frac{1}{v}=\frac{1}{f},$$ people (as per my reference book) tend to apply the sign convention to ...
0
votes
1answer
168 views

Rule sign for concave and convex lens?

I am just totally confused about the rule sign of convex and concave lenses. The general formula: $1/v-1/u=1/f$ Is okay but when solving problem sums sometimes $v$ becomes negative sometimes $u$ and ...
0
votes
2answers
344 views

How to use a magnifying glas or any lens to enhance small light power?

I am currently trying to amplify a tiny amount of light so that a photodiode will recognize it. In order to amplify the light I thought about using a magnifying glass since I got to know that such ...
4
votes
2answers
3k 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 ...
1
vote
2answers
362 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 ...
2
votes
2answers
2k views

Radius of curvature and focal length

Is the radius of curvature of a convex or concave lens longer than the focal length of the lens? Does the center or curvature affect the focal point in a lens?
1
vote
1answer
43 views

When is a negative focal length used in optics?

I'm getting confused with conventions. I was wondering if this logic is correct: If an image appears on the same side of an object, then we use a negative focal length for determining information ...
1
vote
0answers
19 views

influence of soft iron in magnetic lenses

I'm currently working as an intern in a research group which is specialized in transmission electron microscopes. I'm reading a book from David B. Williams and C. Barry Carter : Transmission electron ...
0
votes
2answers
61 views

Can light be rotated using lenses or prisms?

I was wondering if it was possible, by using only lenses, mirrors, or prisms, to rotate a ray of light coming from a certain direction. For example, if I have two lasers beams side by side, is it ...
2
votes
1answer
32 views

Why does this illumination pattern of an LED light going through a small pinhole not emulate the point spread function?

I have an optical setup where a component LED passes through a 50 um pinhole, and creates an illumination pattern on an image sensor approximately 5 cm away that looks like the following: Now, I'm ...
41
votes
6answers
5k views

Do people wearing glasses have different field of view than those who don't?

There is one thing I sometimes wonder about ever since I was a child. Do people who wear eye glasses see objects in different size than those who don't?(Technically different size means different ...
1
vote
1answer
52 views

How to determine the radius of curvature of a convex lens?

Suppose there is an equi-convex lens made of glass which has a focal length ($f$) of 30cm. Then, can we not say that the radius of curvature, $R$ of the lens is twice the focal length, i.e. $R = ...
1
vote
1answer
47 views

Stacking lenses for higher magnification (a DIY microscope)

Recently, I have made a DIY microscope stand for my phone according to these specifications. I am using a lens that I found in home, the closest match that I could find is here. I got some great ...
1
vote
1answer
152 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
426 views

On solving a two lens system

A common method to solve for the image formed due to a two lens system consisting of two thin-lenses separated by a distance is: Locate the (intermediate) image formed by the first lens, ignoring ...
0
votes
0answers
22 views

The sign of a focal length

We know that for converging lens, $f>0$ , for diverging lens, $f<0$. But for many materials I have read so far, it says that: "the focal length of a concave lens is 8 cm." I thought that the ...
0
votes
0answers
13 views

The image of an object through a curved surface

We have a curved surface, separating two different medium, with refractive index n1 and n2. We know the radius R of the curve,then how can we find the position v of the image? I read that the ...
1
vote
0answers
29 views

Given a focal length and an aperture of the telescope, what is its field of view?

While I know FOV of scope is equal to FOV of eyepiece divided by magnification. How can one find FOV given only the focal length and aperture of the telescope?
0
votes
1answer
44 views

The confusion of fractional error calculation

I need to find the focal length of a lens by using equation 1/u + 1/v=1/f I have: u= 50+-3 mm v= 200+-5 mm I calculate the value of f as 40mm. Now i need to find the uncertainty in this value. ...
0
votes
0answers
44 views

Lens formula and Lens maker's formula

When we derive the formula for lens and lens maker's formula using the formula for refraction at spherical interface $$\mu_2/v - \mu_1/u = (\mu_2-\mu_1)/R$$ we put $u$ to be $-u$ as it is on the left ...
1
vote
0answers
29 views

What happens when there is object exactly in the focus of converging lens? [closed]

I was learning some optics and then I wondered what would happen if some object was exactly in the focus of converging lens, more accurately, what would I see if looking from the other side? EDIT: so ...
0
votes
1answer
54 views

Lens combination

Suppose there are two lenses touching each other as shown in the diagram below. the focal length of the lenses are $f_1$ and $f_2$ respectively. Now by using the formula for lens combination I ...
-3
votes
1answer
68 views

Combination of mirror and lenses [closed]

I am a keen learner of physics, but I am unable to solve problems involving lenses and mirrors together. please can anybody tell me the method to solve these problems? for instance let us take a ...
1
vote
2answers
71 views

Can lens designs be brute-force computed to create optically precise equipment? [closed]

It seems lens design hasn't changed much over the last 50 years or so with many older manual lenses still very much being used today. Can the order, distance between and type of lens elements be brute ...
2
votes
2answers
115 views

Experiment to find the circle of least confusion (optics)

I want to conduct an experiment where the circle of least confusion (wiki ref) occurs for a lens. Suppose that I shine white light onto the lens and I know the lens EFL is lets say 100 mm, in order to ...
0
votes
1answer
13 views

What parameters decide the maximum concentration achieved by a fresnel lens?

Fresnel lens can be used for concentrating sunlight for Photovoltaic. What parameters of the lens decide the maximum concentration that can be achieved using the lens.
1
vote
0answers
13 views
0
votes
1answer
40 views

Does 'focal length' mean something different with lenses and pinhole cameras?

Sometimes different but related things have the same name by some tradition or accident, causing a lot of headache to newcomers to a field. I would like to come to clear terms with this: does the ...
0
votes
0answers
31 views

Balance lens tilt aberration

Given a doublet (singlet in reference figure), if the rays enter at an angle with respect to the origin axis, we would see a shift of focal length for blue and red. A known optical jitter How could ...
0
votes
1answer
24 views

Is there any limit to distance between two waves when used in Huygens principle?

when I used Huygens principle to determine the spherical wavuefront of radius $R/2$ created by reflection from a spherical concave lens of radius $R$, I got amazingly different results for different ...
1
vote
1answer
135 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 ...
1
vote
0answers
30 views

Right lens for my laser [closed]

I want to know if there is a way to find out size of lens(radius, it has to be sphere), when i know focal distance(120cm) and refractive index(1.7), for 2cm(diameter) laser ligting on it?
0
votes
1answer
56 views

Confused regarding sign convention of silvered plano convex lens

I'm totally confused while finding the sign convention of a silvered plano convex lens. I know that equivalent power of such a system can be found by adding the power of the mirror and twice the power ...
1
vote
0answers
29 views

I want to make convex lens of focal length 40mm [closed]

i have set of negative meniscus lenses power ranging from -0.5 to -15D made from material whose refractive index is 1.586 please tell how to make a biconvex lens of focal length 40mm
0
votes
0answers
23 views

Effect of introducing lens on Fringe width

Suppose I have a light source of wavelength 400 nm. The slits are placed at a distance 1 mm apart. The distance between the slit plane and the screen is 50 cm. So that makes the fringe width, $\beta ...
1
vote
1answer
54 views

Calculating lens parameters

I have a very bright LED light and I'd like to make this light focus so it forms around 5mm thick strong line (height can be arbitrary) on on an object about 150 mm away. I used a cylindrical lens ...
0
votes
1answer
42 views

Combined function magnet

I am searching how a combined function magnet for accelerator physics works, but on the books that i have and on the web i can find only patents for this thing, that suppose to know already how this ...
1
vote
1answer
190 views

Difference between convexo-concave and concavo-convex lenses?

What is the difference between concavo-convex and convexo-concave lenses? We dont say convexo-plane for plano-convex. Does that mean concavo-convex and convexo-concave are essentially the same?
1
vote
3answers
168 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 ...
3
votes
1answer
49 views

Easy method to measure the NA of a lens system?

I have a lens system made up of some components of the Leica Z16 APO zoom system. This includes a built-in iris diaphragm to adjust the Numerical Aperture (NA) and therefore the depth-of-field (DOF). ...
0
votes
1answer
46 views

Optics - how a lens distorts the image

If we consider a small object of length $b$ that is placed flat along the axis of a concave mirror, how will the image produced be different from the object? I know that a lens will magnify or ...
1
vote
5answers
706 views

Sign convention in optics

Why is the sign convention used in the derivation of the lens formula and yet used again when it is applied in numerical problems? Won't the whole idea of sign convention be eliminated if it is used ...
0
votes
2answers
63 views

Is it possible for two strong lenses to cancel each other effects?

Is it possible for a lens system for 2 strong lenses to cancel each other, so it looks almost the same as a common glass, while at the same time making an object in between them appear big and ...
0
votes
0answers
18 views

Shaving down length of a GRIN lens to a desired wavelength

I have a GRIN lens that collimates light from a point source at 670nm. I want to shave the thickness of the lens down to use for 530 nm. I can't find anything useful for equations online. None seem to ...
0
votes
2answers
65 views

Which one is better 40'' parabolic mirror or 34''x44'' fresnel lens?

I want to make solar concentrator which can reach 2000F or above temperature at focussed spot, so I came across parabolic mirror and fresnel lens but I can't decide which one is better. Also I will be ...
2
votes
3answers
4k views

Change in focal length of lens inside water

I read it on Yahoo Answers (link below) that the power of lens changes when the lens is placed inside water. But then, if we consider the formula f=c/2 , the radius if curvature of the lens still ...
2
votes
2answers
84 views

Cause of Spherical Aberrations

What is the cause of spherical aberrations in lenses? I know that it's due to the differing width of the lens, but I don't understand/know the physics of why the lens width affects the focal distance ...
0
votes
0answers
71 views

Why Double Fresnel Lenses on HMD

I'm creating my own HMD (head-mounted-display), and I saw that nowadays, Double Fresnel Lenses are used for the "Wearality" (HMD, see link below) with a lot of success (I read somewhere that the HMD ...