What is Medium: Definition and 389 Discussions

Medium format has traditionally referred to a film format in still photography and the related cameras and equipment that use film. Nowadays, the term applies to film and digital cameras that record images on media larger than 24 mm × 36 mm (0.94 in × 1.42 in) (full-frame) (used in 35 mm (1.4 in) photography), (though not including 127 sizes), but smaller than 4 in × 5 in (100 mm × 130 mm) (which is considered to be large format photography). In digital photography, medium format refers either to cameras adapted from medium-format film photography uses or to cameras making use of sensors larger than that of a 35mm film frame. Often, medium-format film cameras can be retrofitted with digital camera backs, converting them to digital cameras, but some of these digital backs, especially early models, use sensors smaller than a 35mm film frame. In the film world, medium format has moved from being the most widely used film size (the 1900s through 1950s) to a niche used by professionals and some amateur enthusiasts, but one which is still substantially more popular than large format. While at one time a variety of medium-format film sizes were produced, today the vast majority of the medium-format film is produced in the 120/220 film sizes. Other sizes are mainly produced for use in antique cameras, and many people assume 120/220 film is being referred to when the term medium format is used. The general rule with consumer cameras—as opposed to specialized industrial, scientific, and military equipment—is the more cameras sold, the more sophisticated the automation features available. Medium-format cameras made since the 1950s are generally less automated than smaller cameras made at the same time, having high image quality as their primary advantage. For example, autofocus became available in consumer 35mm cameras in 1977, but did not reach medium format until the late 1990s, and has never been available in a consumer large format camera.

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  1. tworitdash

    I Why different cutoff frequencies for TE and TM in a medium?

    Today in my electro-magnetics class, we were told that the cut-off frequencies of TE and TM waves on a co-axial cable are different. As far as I understand, it says that if there is an electric field with one frequency projected on it and if we know that the problem can be simplified if we see...
  2. AwesomeTrains

    Effective refractive index of a stratified medium

    Hello PF, I'm reading a paper for a project. In the paper they derive an equation for the effective refractive index ##n=\sqrt{\epsilon^{e} \mu^{e}}## of two stacked layers ##(n_1^2 = \epsilon_1 \mu_1, a)## and ##(n_2^2 = \epsilon_2 \mu_2, b)## where ##a,b## are the lengths and in my case...
  3. jk22

    Is classical Snell's law with a moving medium solvable?

    Considering classically a light ray in a medium with lightspeed ##c_1## and entering a medium with lightspeed ##c_2## moving with speed ##v## along let say ##y## in the plane of the interface, is it correct to obtain a very complicated formula, having even 3rd power of trigonometric functions of...
  4. Krushnaraj Pandya

    Solving the Standard Potential of NO in Alkaline Medium

    Homework Statement in acid medium the standard reduction potential of NO converted to N2O is 1.59V .its standard potential in alkaline meduim at 298k would be? Homework Equations a)2NO+2H ---> N2O +H20 E=1.59 b)2NO + H2O ---->N2O + 2OH- E=x c)2H2O---->2H+ + 2OH- E=0.826 (calculated...
  5. R

    Oscillations of Spring with Viscous Medium

    Homework Statement A spring with K=12N/m and an attached bob oscillates in a viscous medium.Amplitude is 6cm from equilibrium position at 1.5 s and Next amplitude of 5.6 cm occurs at 2.5s. what is its displacement at 3s and 4.5s and t=0s Homework Equations x(t)=Xme^-bt/2m The Attempt at a...
  6. K

    I Consequences of light moving in a medium

    I'm reading Special Relativity by TM Helliwell and in it he describes the second postulate and the fact that moving with respect to air changes the speed of sound, and that because light doesn't need a medium it's speed is constant. I remember my physics teacher saying that light itself(EM...
  7. E

    Why the Frequency of Light Does Not Change Through a Medium

    My question is about why the frequency of light or another EM wave does not change while passing through a medium. We know their Speed decrease and wavelenght change but think about this analogy for ex i am 4 meters high and drop 5 balls in 5 seconds and my friend waits at ground he will receive...
  8. M

    Can a photon travel slow enough to be seen by the naked eye

    Please see my attachment of a recent observation of light traveling through a medium. There is no source, just my observation The packets of light appear to be visible, distinct , moving at different speeds, and display the various colours for each wavelength. Is this normal / possible in a...
  9. P

    An Electromagnetic wave goes from air into a medium....

    Homework Statement An EM wave from air enters a medium. The electric fields are --> ^ E1 = E01 cos(2πv(z/c-t) x --> ^ E2 =E02cos(k(2z-ct)x in a medium ,where the wave number k and frequency v refer to their value in air.the medium...
  10. W

    Multiphase flow through a porous medium

    I am simulating flow through porous medium with VOF method and species transport. For phase change i have Lee Model, and i have no idea about the evaporation frequency and condensation frequency Second I am using the evaporation frequency as 30. The liquid is n-heptane while for vapour phase i...
  11. P

    Is the index of refraction constant for a given medium?

    If we have a medium (say, glass) with an index of refraction, n=1.33, the speed of light in it will be c/1.33. However, blue light travels slower in glass than does red light. Since c is constant and the speed of light is changing, doesn't that mean that the index of refraction will vary based...
  12. Harsha Avinash Tanti

    I The Role of magnetic field during the formation of small to medium scale stars

    Hi, I would like to raise a question about Role of magnetic field while formation of small to medium scale stars emerging from nebula ?
  13. F

    Is Plate Capacitor Gap a "Non-linear" Medium?

    Could the space (air gap) between two DC charged parallel plates be considered to be a "non-linear" medium with respect to an EMF radiated by a coil contained within that space?
  14. A

    How Do You Model Free Fall with Air Resistance in Differential Equations?

    <Moderator's note: Moved from a technical forum and thus no template.> An object with mass 96 kg is given an initial downward velocity −3m/s in a medium that exerts a resistive force with magnitude proportional to the square of the speed. The resistance is 60 N when the velocity is −2m/s. Use...
  15. G

    I How energy of light is conserved when passing through medium

    The velocity of light changes when it passes through a medium of a different refractive index. So let's suppose the light is traveling through a vacuum at a velocity c and then passes through a glass wall. Its velocity decreases while traveling through it but then speeds back up to c after...
  16. A

    Turbo-Jet Engine for Medium RC Aircraft

    Hello , I am thinking to work on a RC aircraft ( Airplane ) that can load a small supply of Medical Firstaid in small range. So I need to make it fast and stable. So I'm thinking to use a small Turbo-jet engine in it which will be home-made. Please suggest me -- (1) Is that makes any sense ...
  17. Vavi Ask

    How Is MnSO4 Oxidized to MnO4- in an Acidic Medium?

    Homework Statement In the laboratory how is MnSO4 oxidised to MnO4- in an acidic medium? a. NO3- b. O2 c. Cr2O72- d. S2O82- (NB: If I've posted this question in a wrong thread please tell me exactly the right place to post it rather than just deleting it and saying to post it in the right...
  18. P

    Motion of a particle in a magnetic field and viscous medium

    Homework Statement In a homogeneous, non-magnetic, highly insulating and viscous medium, a moving particle experiences a viscous drag given by the law f→=−bv→. Here b is a positive constant. A particle having charge q is projected with an unknown velocity from a point in the medium. It almost...
  19. redtree

    I Can Dispersive Media Be Modeled Effectively as Fields?

    I am studying phase and group velocity in non-dispersive and dispersive media. My question is the following: Is there any reason why a dispersive medium simply cannot be modeled as a type of field?
  20. T

    Max current densities in a conducting medium

    Hi, I am looking for some information regarding maximum current density in conducting mediums, such as a conducting fluid. Say that we have a setup like the figure that I have attached. We are looking down on a conducting medium with a uniform magnetic field coming out of the page and the...
  21. H

    Light in a medium: do phonons store light energy?

    When light travels through a transparent medium and is absorbed then re-emitted, do the phonons just move to a higher energy state after absorption? Is it the same as absorption and re-emission of light by electrons, aside from having a continuous range of available energies?
  22. Killtech

    I What is the General Form of a Wave Equation in a Medium?

    Hi, i am looking for a general form of a wave equation in a medium. i am not looking for a concrete physical equation but rather a generalized form (preferably in n dimension) of such under the simplest assumptions (it's of course a little equivocal what 'simplest' means but, well). so for a...
  23. FallenApple

    I Are QFT fields the medium for light?

    It is said that light needs no medium. But light is just an excitation of the electromagnetic field in QFT. This excitation presumably propagates within that field at the speed c and once that excitation has left a point in space, the field has settled down to 0 energy again, analogous to pond...
  24. hilbert2

    I New possible explanation for Hubble redshift

    I just saw this news article on the home page of the university I'm working in: http://www.aalto.fi/en/current/news/2017-06-30/ It seems to be about a study that can potentially explain the redshift of distant stars with a mechanism that's related to the interaction of photons with the...
  25. R

    Partition function for ideal gas for "medium" temperature

    Looking for the heat capacity of ideal gas due to rotational degrees of freedom. If the temperature of the gas is much higher than the temperature corresponding to the energy differential between states,the partition function can be written as the integral over the density of states. If the...
  26. T

    Gain of active semiconductor gain medium

    Homework Statement Homework Equations γ=α+(1/2L)ln(1/Γ1Γ2) where gamma is gain, alpha is absorption constant, and Γ are reflection coefficients. The Attempt at a Solution I'm a little stuck on how to start. If there was no semiconductor gain medium in the cavity then I could just use the...
  27. M

    Concepts at play with polarization?

    Homework Statement Homework Equations Brewster's angle The Attempt at a Solution I understand why A is true, but I have no idea what concepts are at play with B, C, and D. Any suggestions?
  28. E

    I Dispersion: expansion of wavenumber as function of omega

    Hi! Dealing about wave propagation in a medium and dispersion, wavenumber k can be considered as a function of \omega (as done in Optics) or vice-versa (as maybe done more often in Quantum Mechanics). In the first case, k (\omega) \simeq k(\omega_0) + (\omega - \omega_0) \displaystyle \left...
  29. F

    Optical system with a medium different from air

    Hi all! I have an optical system made up like this: Circular led source -> smaller circular diaphragm -> circular even smaller lens -> cmos sensor at the posterior focal plane This is the in scale model: The image is optically after the focal plane, but practically it will lie on it due to...
  30. pallab

    A 300 MHz plane wave propagating through a non-conducting medium

    Homework Statement A 300 MHz plane wave propagating through a non-conducting medium having relative permeability= 1, relative permittivity= 78.What is the velocity of light in this medium? Homework EquationsThe Attempt at a Solution n=√(78) v=c/n =3*108/√78[/B]
  31. Dr Wu

    Traveling through the Interstellar Medium

    I understand that the interstellar medium (ISM) consists mostly of neutral hydrogen gas, plus a smaller fraction of helium gas. Furthermore, I gather that between 0.1 and 1.0 atoms per cm3 correspond to the average density values pertaining in our "Local Bubble". The above, however, refers...
  32. A

    Can photons act as medium for sound?

    can light collectively or individual photons act as a medium for propagation of sound waves?
  33. John Doe

    I Amplitude of particles in the medium of a longitudinal wave

    I was thaught you can create a sinusoidal wave by making a source oscillate with simple harmonic motion in a medium, such as moving one end of a rope up and down to create a periodic transverse wave. For transverse waves, it is easy to see that every particle in the rope moves up and down with...
  34. Theudius

    Does Frequency Change in a Medium?

    Hi I was told by physics lecturer that both the wave speed and wave length of light changes when it enters a medium, however I questioned this stating that if both wave speed and wave length changed then frequency must also according to the formula c = fλ. He stated that "frequency is energy...
  35. V

    I Derivation of phase change parameter in dispersive medium

    Hi, I'm trying to evaluate the derivates of first, second and third order of the phase change parameter in a dispersive medium. In such medium the refractive index is a function of the wavelength. In my case it depends on the wavelength in vacuum. \begin{equation*} n(\lambda_0 )\end{equation*}...
  36. C

    Path of light in a medium with increasing refractive index

    Homework Statement A medium has a refractive index, ##n(y)=n_0 \sqrt{1+y/a}## which increases along y. Assume ##n_0## and ##a## are constants and always positive. If a light beam enters horizontally along y, through (0,0), find the curve the path of the light ray takes. Homework Equations ##F...
  37. I

    Why does light move slower in a more dense medium?

    As I understand it light is refracted when entering a different medium (like from air to glass to air) because it moves slower through the glass, so it will go through the glass in as least time possible , so it bends toward the normal so it can traverse the glass quickly (if that's right word...
  38. G

    I What is the Role of Space in this Apparatus?

    Here is the picture of my apparatus.
  39. G

    I Is the fabric of space a "medium" for light?

    For this question, I don't want to explore what "space" is (quantum chaos or otherwise), or whether it has mass, etc. Instead, I just want to explore if it qualifies as a medium, like air or water. I have a line of reasoning I want to explore, but as it is based on "space" being considered a...
  40. L

    Optical detector sensitivity at low and medium flux

    Dear all, This is my first post and I'm not sure if it's the right place to ask so don't hesitate to advise if necessary. I would like to know if it's possible that an optical detector (the complete system including sensor and front-end electronics) has a better sensitivity at medium flux than...
  41. Surya97

    Why is there a set speed of sound in a certain medium?

    Why does sound always move at the local speed of sound in a medium (in other words, why is there a set speed of sound for certain medium)? I understand that sound is a compression wave, but shouldn't a louder sound (i.e. one with a higher amplitude) move faster? What about a higher pitch noise...
  42. Dee Flont

    B Is the smooth dark matter deBroglie's subquantic medium?

    https://www.inverse.com/article/24863-dark-matter-might-be-smoother-than-we-thought Scientists have yet to actually observe dark matter in the flesh, but most research up to now posits it’s the kind of stuff that clumps up and aggregates into unwieldy masses around the universe. New research...
  43. A

    How to find the speed of light practically?

    Currently, I'm doing the CREST award for physics, and my topic is about different methods of finding out the refractive index of a medium. I have already tested out few ways, and now i am thinking about a method where a formula n=c/v will be used(n-refractive index, c-speed of light in vacuum...
  44. T

    Fields of Rotating Dielectric Sphere in Dielelectric Medium

    Homework Statement A dielectric sphere with the electric and magnetic susceptibilities ε1 and µ1 is rotating with angular frequency ω in a constant electric field E~ in a medium, characterized by the parameters ε2 and µ2. The angle between the rotation axis and the direction of E~ is α. Find...
  45. M

    Use of solid materials as medium for data transfer

    Really odd question for you guys but I'm curious about your input, and apologies if it's a foolish question to ask anyway(I'm a CS student and this came up in a discussion with a classmate of mine). So I know this is a fairly odd thought and not likely practical in any real world scenario, but...
  46. A

    What medium does light move in?

    Waves on water require water to move, sound waves require a medium of the like. My question is what do light waves move in. Empty space contains not much more then low density hydrogen, what medium could light possibly be moving in.
  47. P

    Permittivity of a Lossy Medium using Antennas

    First of all I will being with I'm not an electric engineer so I might be out of my wits, but I will give it a try. So I have an instrument which reads relative permittivity using a transmitter and two receiver placed at different distances. The instrument is calibrated to read either in a...
  48. L

    Relationship between speed and density of a medium

    So my question is, is there a relationship between the density of a medium you are traveling through and the maximum speed achieved for an object of constant mass and shape traveling with constant thrust in both mediums? for example if i knew that an object traveled 8 times faster in 1 medium...
  49. G

    I How Does Gravity Propagate Through Different Mediums and Energy Fields?

    It is clear that gravity propagates at the speed of light in the vacuum. But what happens to gravitational waves as they propagate through material mediums? Presumably they get slowed down but, is it known precisely how much and by which factors, density of the medium or any other properties...
  50. T

    Optimizing sound energy transfer through plastic medium

    Hi everyone, I am looking to improve the transmission of sound from a small 1/2" electro-mechanical transducer through a plastic medium (about 1/4" thick). I understand plastic is not a great medium for this but I do not have the ability to change this. The defacto setup doesn't work too...
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