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2
votes
1answer
31 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 ...
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
31 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 ...
1
vote
1answer
51 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
46 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 ...
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 ...
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 ...
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
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
43 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 ...
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 ...
1
vote
0answers
13 views

What is the maximum concentration ratio achieved for CPV (concentrated photovoltaic)? [closed]

CPV uses ratios in the range of 100-1000. On what lens parameters does it depend.
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.
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 ...
2
votes
2answers
114 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
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 ...
-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 ...
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
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
28 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
187 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?
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 ...
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
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
64 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
2answers
81 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
70 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 ...
-1
votes
1answer
65 views

Designing a lens

What factors would I have to take into account when designing a lens. For instance, I want to design a lens that has a focal length of approximately 20 cm, and it is intended to be used for ...
0
votes
2answers
60 views

Image formation by a convex lens without a screen

The real image of an object placed between f and 2f from a convex lens can be seen on a screen placed at the image location. If the screen is removed, would the image be still perceived? Is the image ...
1
vote
1answer
60 views

How can the active area of a photodiode increased?

I use photo-diode VTB8440BH. To increase its active area I was thinking to put a lens in front the diode would enlarge its active area. What kind of lens would be beneficial one? I was thinking of a ...
2
votes
1answer
59 views

How to transmit light ideally through not parallel tiny holes within a metal case?

I currently try to transmit light through a tiny hole of one side of a metal case in order to receive the light on the other side of the case. The tiny holes are not parallel (see image 2). Using ...
0
votes
1answer
124 views

How to calculate the diameter of a thin lense?

A photo produced with a single thin lense is provided. Only based on the photo I should calculate the diameter of the lense. The photo shows a ruler in the foreground and a point source of light in ...
1
vote
1answer
74 views

How does light focused through a lens create bokeh (blurry background)?

This question is relevant, though I don't think it quite answers the question. From a photography perspective, when you open the aperture wide (with a small f-number) you get a very shallow depth of ...
1
vote
1answer
91 views

Spherical and chromatic aberration correction

I have some spherical lenses which are 5mm, 1mm and 0,5 mm in diameter, having 100x, 350x and 1000x magnification respectively. While looking at blood samples, I'm having big problems with spherical ...
0
votes
0answers
31 views

Singular isothermal density distribution

Does anyone know where the Singular isothermal density distribution $$ \rho(r)=\frac{\sigma_{V}^{2}}{2\pi\,G\,r^{2}} $$ or how it was derived. Are there any good references on how this equation was ...
1
vote
2answers
129 views

Is it possible to calculate the dimensions of ANY object in a picture having at some known distance an object on know dimensions?

Is it possible to calculate the dimensions of ANY object in a picture having at some known distance an object on know dimensions? I'm thinking about the scenario where someone is holding a smartphone ...
0
votes
0answers
33 views

Why do acoustic lenses need air channels?

In every design of an acoustic lens I have seen so far, be it Fresnel lens or GRIN lens, there are always air channels included in the design. I don't see why this is needed. Couldn't a lens be built ...