What is Cameras: Definition and 46 Discussions

A camera is an optical instrument that captures a visual image. At their most basic, cameras are sealed boxes (the camera body) with a small hole (the aperture) that allows light in to capture an image on a light-sensitive surface (usually photographic film or a digital sensor). Cameras have various mechanisms to control how the light falls onto the light-sensitive surface. Lenses focus the light entering the camera, the size of the aperture can be widened or narrowed to let more or less light into the camera, and a shutter mechanism determines the amount of time the photo-sensitive surface is exposed to the light.
The still image camera is the main instrument in the art of photography and captured images may be reproduced later as a part of the process of photography, digital imaging, photographic printing. The similar artistic fields in the moving image camera domain are film, videography, and cinematography.
The word camera comes from camera obscura, which means "dark chamber" and is the Latin name of the original device for projecting an image of external reality onto a flat surface. The modern photographic camera evolved from the camera obscura. The functioning of the camera is very similar to the functioning of the human eye. The first permanent photograph was made in 1825 by Joseph Nicéphore Niépce.

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  1. E

    Engineering Minimum number of pixels of the image sensor to identify an object?

    ##d/2F = U/2D## ##d'/2F = 0.01U/2D## d' - the size of the object's reflection on the image sensor ##pixels size = d/N ## since we want N to be minimal, the pixel size should be maximal: pixels size = d' hence : ## N = d/(pixels size) = d/d' = 100 ## My final answer does not depend on U...
  2. AmericaPacific42

    Algorithms for quadcopters to use back-EMF to detect obstacles close?

    Would it help to study Verilog (VHDL) or Field-Programmable-Gate-Arrays (FPGA) if self-crafted x64/aarch64-assembly would take too much power/be too slow?
  3. anorlunda

    Surveillance Cameras for Pilots

    Most of us have cars with backup cameras. They are inexpensive, simple, lightweight, and reliable. Teslas have as many as 7 cameras looking in all directions. I think that cameras showing views of wings, stabilizers, rudder, engines, landing gear, cabin, cargo hold, would be of great use to...
  4. L

    B Infrared Cameras -- Do they use a Lens to Focus?

    Can infrared cameras focus IR radiation as a visible light camera focuses visible light? I think IR doesn't pass through glass well? What are these germanium lens about? I don't think my Flir IR camera has a lens.
  5. rudransh verma

    Analog to digital signal converter in digital cameras

    I am reading How computers work and I don’t grasp it. So how is light ultimately get transformed into a beautiful picture on screen in a digital camera? I have got D5200 Nikon. It’s a nice begineers camera.
  6. berkeman

    Gyroscopic stabilization and the cameras used in MotoGP on-bike video feeds

    For many years, the on-bike cameras in Sportbike/Superbike/MotoGP racing showed the leaned images tied to the bike that the cameras were mounted on. Great stuff, but the new camera video from some of the MotoGP bike camera feeds for the last few years have included gyroscopic horizon...
  7. hagopbul

    B Viewing IR radiation with cell phone cameras

    Hello All: i saw some youtube videos on testing IR controllers on normal with no add ons Cell phone camera and the cell phone screen is showing signal emitted by the IR LED of the remote controller , how the cell phone camera sensor are able to register a signal from an IR LED , the pixle in...
  8. prashantakerkar

    Recording plays with CCTV cameras in an Auditorium

    Is it feasible to install CCTV cameras for recording Plays and Dramas in Auditorium? The CCTV cameras should be positioned properly to get complete 360 degree view of the location where the play or drama is running in the auditorium. Thanks & Regards, Prashant S Akerkar
  9. José Ricardo

    B Human Eyes vs Cameras: Exploring the Limits of Perception

    When the camera can oversee the human eyes?
  10. F

    Infrared Cameras Spectral Range and Derived Temperature

    Hello Forum, I am wondering why infrared cameras can only detect radiation between 1micron to 15micron. This clearly depends on the sensor's material. Based on Wien's law, this corresponds to temperatures from -79C to 89C. Are infrared cameras only detecting within this spectral range because...
  11. K

    Motion involving speed cameras

    Homework Statement Homework Equations [/B] Equations of motion: v = u + at s = 1/2 (u + v) t s = ut + 1/2at^2 v^2 = u^2 + 2as 3. The Attempt at a Solution Hello, on a i used the 2nd equation: 30m = 1/2 (3*10^8m/s+3*10^8m/s) t so -> t = 1*10^-7s but to get the correct solution i...
  12. chastiell

    Is perspective distortion mathematically modeled?

    Hi guys ! I'm trying to understand the perspective distortion that can be observed in our vision and cameras, so many pages on the web that talks about photography says that the perspective distortion can be controlled using different focal lengths lenses, meanwhile a reduced group of pages...
  13. DaTario

    Cameras detecting Infrared and making it visible

    Hi All, It is known that ordinary cameras can make infrared radiation which comes from remote controls visible at their own display. My question is about the explanation of this fact. Is the electronic process simple to describe? It seems that the infrared can produce photocurrents which are...
  14. Clever Penguin

    Do speed cameras use interferometers, and how do they work?

    If they work like I assume they do, by comparing the wavelength emitted with the wavelength reflected back, they might use an interferometer. If so, how does it work?
  15. Andy Resnick

    Insights Digital Camera Buyer's Guide: Real Cameras - Comments

    Andy Resnick submitted a new PF Insights post Digital Camera Buyer's Guide: Real Cameras Continue reading the Original PF Insights Post.
  16. T

    Distance measurements with two cameras

    Hello, I would like to know if there are simple ways (using trigonometric functions) to calculate distances between an object and two cameras. I am using two CMUcam5 (pixy), closely placed (the distance between the two cameras is known). And I would like to calculate the distance between the...
  17. G

    How do cameras focus on reflected images?

    I can remember from my distant school physics days that the image in a mirror lies beyond the mirror. But how does a modern camera sensor "know" this. If I face a mirror with my canon camera which has a cmos sensor and usm lens, it autofocuses correctly on the part of the reflection I select...
  18. A

    Do multiple lens cameras refract light differently to a single lens ones?

    Why do high end camera modules have so many glass lenses, apart from the necessary lenses for focus and zoom why is it that in cameras like DSLR cameras there are so many low power lenses where a few high power ones would work do the same job, do the lenses diffract light differently when...
  19. F

    Infrared cameras and IR sensors

    Hello Forum, Why are infrared (thermal) cameras, those that produce interesting thermographs of objects, mapping their surface temperature, so expensive? IR sensors are ubiquitous and very inexpensive...What is the difference? thanks, fog37
  20. J

    Is there a wavelength shift in the way digital cameras represent color

    After going on a ghost tour over Halloween, several people were able to take photos of ghosts seen through an old hotel window, a few stories above our position. This got me to wonder if this was a trick that relied on the way that the digital cameras may be able to detect non-visible...
  21. B

    Sensors and Cameras for Local Space Analysis

    I've been looking all over and it appears like I may be using the wrong words to really get a solid answer. I figured I would ask here and maybe someone could either give me a few better terms to help my search or would know the answer already. Thanks in advance! I'm working with a team...
  22. nsaspook

    Red Light Cameras being abused again in FLA.

    http://www.wtsp.com/news/local/story.aspx?storyid=316418 Cutting yellow light times increases revenue but decreases safety. http://saferstreetsla.org/590/data-safety-benefits-longer-yellow-signal-times/
  23. M

    Cameras inside Dounreay Reactor

    Hi All... Just popped up in my news feed: - http://www.bbc.co.uk/news/uk-scotland-highlands-islands-22292053 Could be interesting although there's only one image of the inside on the BBC news item. And - to dismantle it: -...
  24. N

    Latest high frame rate consumer priced video cameras?

    I'd like to get images at a frequency of at least 100 frames/sec to measure servo arm speeds (including acceleration from rest) under various torque loads. This is for personal research associated with RC helicopter accessories, but as a high school physics teacher it seems it would be good for...
  25. F

    Solving LAG Issues in IP Cameras - Hello Forum

    Hello Forum, I have an IP camera that has some amount of LAG from when the movement occurs to when it shows up in the browser. What causes that? If I bought a more expensive camera would it the lag disappear? the camera works well with Internet Explorer (remotely). but It is terrible...
  26. J

    Mars Rover "Curiosity" Camera Specs

    what resolution are the cameras on the new Mar's rover "Curiosity"? i read somewhere that the high-res cam was only 2mp, but i am unable to find any real specs. thanks.
  27. Pengwuino

    16MP Cameras Explored - What You Need to Know!

    16MP Cameras?? I've been in the market for a new digital camera and I've noticed something odd. Back when I last even looked at digital cameras, everything was 6MP-8MP at the most. People said that sensors over 6MP were useless because the standard sensors at the time were so small that some...
  28. C

    Understanding the Science of Flash in Cameras

    Homework Statement how is flash created? The Attempt at a Solution flash makes images caught on a camera brighter and the background dark. why does this happen? what exactly is flash made up of? how do you explain the effects of flash?
  29. Aaronvan

    Understanding Spark Cameras: A Brief Overview

    I’m not sure if they are even used anymore, but back in the day engineers used spark cameras to capture very brief timescale events.
  30. P

    How Can Digital Cameras Possibly Capture Violet Light?

    First, I am curious about why CCDs need color filters in the first place. It is said that they are necessary because digital camera sensors can only sense intensity of light, but not wavelength (color), which makes sense initially... except that CCD sensors operate by utilizing the photoelectric...
  31. A

    GPS in cameras and phones creates privacy issue

    This is scarey .. http://abclocal.go.com/wabc/video?id=7621105
  32. J

    How do digital cameras capture images using the photoelectric effect?

    So they use the photoelectric effect right? Does that mean when the camera takes a picture it allows photons of light to interact with a sensor for a certain period of time? How does that create the picture? If i understand it correctly the different photons have different frequencies and their...
  33. Borg

    What are the pros and cons of using IP cameras for home security?

    There have been two break-ins in our neighborhood in the past two months which got me to thinking about security cameras. This is my first day researching security camera installations. I didn't know anything about IP cameras before today and didn't even know that they existed (I didn't realize...
  34. J

    Creating an Electrical Wire Corona: Voltage, Amps & Cameras

    Does anyone know what current voltage, amps would be required to produce a corona around an electrical wire? I gather that this would also be dependent upon the wire material and size. I have seen photos of this and would like to do reproduce the process. What type of camera may these...
  35. J

    Optics question - eyes and cameras, and the mythical 50mm lens

    Eyes and cameras - a topic that has been troubling me Hi all. This is my first post. I'm seriously thinking about applying to optometric college in the fall. I'm trying to improve my knowledge as much as possible of the area, and one question that keeps coming up (I'm a hobby photographer...)...
  36. O

    Exploring the Differences Between CMOS and CCD Cameras

    Hello, What are the important differences between CMOS and CCD? I am studying the digital cameras
  37. P


    Hi all Is it possible that a RADAR speed camera, (the type that bounces off the road and is reflected off the vehicle and then the doppler shift represents the vehicle speed) can be affected by a raise in surface temperatue on a very hot day(40 degrees C plus, poster is in Australia) I...
  38. C

    Infrared cameras for detecting people inside cars

    For an experiment we are doing, we need to be able to accurately detect people inside a car moving at high speed. Any suggestions for an IR/other camera that can help us effectively do it? The car has a hot engine, so I am concerned an IR camera may or may not work. Any thoughts. Cost not a...
  39. M

    Can the other two cameras provide a better pictuer?

    I have a camera (Camera 1) that has the specifications: 3 mega pixel resolution, 10x optical zoom, 120x digital zoom. The camera can see an object which is 100 feet away from it. Now, I have two other cameras. Can the other two cameras also see the object? Will the object be less clear? Out...
  40. E

    Can Thermal Cameras Help Reduce Epidemic Spread More Effectively Than Vaccines?

    If thermal cameras (TC) could be cheap, they could be located in many buildings and the can have huge efect on reduction of epidemics spreading. (Do you agree?) One TC cost around 10000$. What is the problem for world consensus for research for cheaper thermal cameras? It is cheaper and with...
  41. M

    Can cameras see through clothes?

    Does anyone have any experience of this kind of optics or is this just another hoax? http://www.davidsteele.com/X-ray-Vision-Camera-Lens-p/xr-l.htm
  42. P

    Optics and Cameras: Why Does a Camera Get Wider/Longer?

    Homework Statement Why does a camera get wider/longer? Homework Equations N/A The Attempt at a Solution Well, I assume that it is to produce the largest image that can possibly be on the film. But I'm a little confused on the question as a whole? Am I on the right track and...
  43. P

    How is physics involved in the application of cameras?

    So for a project I am asked to give examples of how cameras are used. Of course the obvious use is clear, but how else (hopefully physics involved ways) are cameras used? Forgot to mention, my project is on photographic not digital cameras.
  44. K

    How Do Physics Principles Influence Digital Camera Technology?

    Homework Statement What physics principles are applied to the design and use of digital cameras? 2. The attempt at a solution • Charging the battery requires electrical and magnet field use from the source it is obtaining the energy from. The battery creates electric potential...
  45. D

    Unraveling Auto Focus: Cameras and Math

    hello, i am not sure that this is the correct forum to post in, but i am confident that the moderators can swiftly correct my error if that is the case. I was wondering a little about cameras and their auto foucs. How does it work and what is the math behind it?
  46. arivero

    Do TV Cameras & Tanks Have Autofocus & Alarm Systems?

    do TV cameras have autofocus? and, do USA tanks have some alarm system telling them if they are been targeted with an IR system?