What is Photo: Definition and 505 Discussions

A photograph (also known as a photo) is an image created by light falling on a photosensitive surface, usually photographic film or an electronic image sensor, such as a CCD or a CMOS chip. Most photographs are created using a smartphone/camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process and practice of creating such images is called photography.

View More On Wikipedia.org
  1. S

    Classical Help with identifying the textbook

    Recently I stumbled upon this topic - https://www.physicsforums.com/threads/simple-harmonic-motion-total-energy.736484/ and want to find out what textbook is in the photo. Any help would be greatly appreciated!
  2. S

    I Which one is Antares in this photo?

    https://en.wikipedia.org/wiki/Rho_Ophiuchi_cloud_complex#/media/File:Antares_and_Rho_Ophiuchi_by_Adam_Block.jpg The caption says it's the yellow one (false color), but there are 2 such yellow stars, one that is in a clear area, and one that has a cloud around it. Whenever I look (naked-eye) at...
  3. Suppaman

    B How to calculate size of objects in digital photo

    Please move to a better forum if available. We have two friends discussing their photography efforts. "you know that your photo of people with large one-inch square buttons on their coats will not look accurate," said Moe. "Why is that," asked Curly. Moe answered, "You have the model...
  4. T

    How do I reference a photo taken from the assignment question?

    How do I reference a photo taken from the assignment question in Harvard style?
  5. anorlunda

    How Can a Digital Photo Frame Revive Old Memories and Connections?

    I discovered something really fun, that I would like to share. I bought a cheap ($30) digital photo album. It is cheap because it has no memory, just a USB port for a thumb drive. I also have more than 29 thousand pictures in my folders, some on the hard disk, some in the cloud. I even...
  6. S

    B Meteor Photographed by Accident: Spectacular Green Bolide

    https://www.goodshomedesign.com/photographer-gets-once-in-a-lifetime-shot-of-meteor-by-accident What would make a bolide be green? Copper?
  7. ezfzx

    B Photo of crosswalk lines distorted by tires action-reaction

    We've all seen these photos of the crosswalk (or other street lines) on the asphalt distorted when the driven tires of cars push back as they roll forward. (At least I'd like to think we've all seen them.) I used to have one I took myself a long time ago. But, for the life of me, I can't seem to...
  8. Greg Bernhardt

    Toonify yourself and post the photo

  9. P

    I Troubleshooting Calculator Issues: Wolfram & Equation in Photo

    I have the problem with checking solution in calculators. For example wolfram doesn't give result of this equation. Have you any idea what is going on? Maybe should I simplyfy something. The equation is placed in photo.
  10. ZapperZ

    VOTE Photo Contest - Dawn to Dusk

    {Administrative Note: This was the last PF Photo Contest that I administered. It has been a great run since I started this contest more than 10 years ago on this forum. Thank you to everyone who had participated in it. It was fun (most of the time). Special thanks to long-time participants...
  11. P

    The Attempt: Captured in a Photo

    The attempt is in the photo
  12. morrobay

    For Photos You Should Have Posted Instead, In The Photo Contests

    Should have , could have , would have. I hope I am not the only one who has had second thoughts on the photo that was posted in any particular photo contest. This for the 'You Look Rather Down'contest.That I should have posted.
  13. E

    Here is an interactive 360 degree panoramic photo of a 3D model I made

    Here is an interactive 360 degree panoramic photo of a 3D computer model I made of the RBMK-1000 nuclear reactor central hall. The refueling crane is a work-in-progress. https://www.artstation.com/artwork/A9BAJm
  14. R

    Would a longer lever require less force to hand pump water? (PHOTO)

    I think that it would take less force to pump water based on the lever principle. But I'm not so sure! Here's a drawn photo.
  15. T

    A What does the first ever photo of quantum entanglement look like?

    A photo: https://petapixel.com/assets/uploads/2019/07/quantum.jpg The popular press version (with above photo): https://petapixel.com/2019/07/13/this-is-the-first-ever-photo-of-quantum-entanglement/ The full paper in Science Magazine: https://advances.sciencemag.org/content/5/7/eaaw2563
  16. V

    MHB Identifying Celestial Pole in Photo Taken 02/21/2010

    I took this picture on 02/21/2010, and I saw a line that I called it celestial pole. But I am not sure if that is what I see in the picture I took. I looked up wiki and I found that picture that the celestial pole is on the other side of the line that I see on my picture. How do I explain it...
  17. N

    I Can you explain this photo to me?

    I took this photo, which is of the flashlight on another phone, and I was just hoping someone could explain why it looks the way it does to me. (The pink circles, the blue half halo etc.) Just in case the uploaded image doesn't load for you, here is a direct link to the image...
  18. Wrichik Basu

    Best online free photo storage option?

    I was comparing online photo storage options. I mostly use Google photos, but Google account has only 15GB of free storage. Moreover, after Picasa web albums was discontinued, embedding photos has become a problem too. Can you recommend me sites where I can store unlimited number of photos...
  19. Pushoam

    Photo of rotating scale and falling coins

    Homework Statement Homework EquationsThe Attempt at a Solution The option (a) says that the 1st coin remains at its earlier position. Due to gravitational force, the 1st coin falls down, hence option (a) is wrong. I don’t understand the difference between option (B) and (C). In my opinion...
  20. bruha

    Stargazing Stunning Telescope Photo of Vega Captured with 130mm Eyepiece - See the Beauty!

    Hello, I made some photos of Vega..just by mobile camera through telescope 130 mm eyepiece 12,5 mm. Fig. "vega_cam" is made by usb camera eyepiece adapter but I did not manage to focus it properly..
  21. bruha

    Stargazing Vega & Arcturus: Amazing Telescope Photos

    Hello, I just try to make photo (quite amateur) of Vega and Arcturus (by 76 mm scope Newtonian) If you like watch it ...
  22. Farang

    How many people can you recognise in this photo?

    I recognise Dirac and Schrodinger only. Can you name others?
  23. V

    A photo of the computer screen -- what causes vertical lines

    https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 I have question what causes vertical lines on the photo of the screen of my laptop? But I would like to find out it alone. Could someone lead me? I know...
  24. larry909

    B Is this Saturn photo real or an artist's rendition?

    It's hard to beleive, it looks so uniform and like it was drawn. https://saturn.jpl.nasa.gov/system/resources/detail_files/7547_PIA20506_full.jpg Webpage of photo: https://saturn.jpl.nasa.gov/resources/7547/?category=images
  25. Planobilly

    Photo of the new amp in the case

    Hi Guys, This was my first attempt at trying to make a case and covering it. I made a few mistakes and learned a good bit about the process. I think I learned enough to do a good job on the next one. Education is never cheap...lol The amp is basically a AB763 with a few mods. The current...
  26. Greg Bernhardt

    Funny photo caption contest (Bill Nye)

    Can you write a funny caption for this photo?

    What Is the Maximum Kinetic Energy of an Electron in the Photoelectric Effect?

    Homework Statement The photo electric effect threshold wavelength of silver is 2762A(angstrum) Homework Equations Calculate the maximum kinetic energy of electron? The Attempt at a Solution since no work function then how can I slove this? Is this be sloved by E=hv-Φ?
  28. Greg Bernhardt

    Insights Name the Science Photo - Comments

    TheAdmin submitted a new PF Insights post Name the Science Photo Continue reading the Original PF Insights Post.
  29. DiracPool

    A single photo to define your character

    Can you find a single photo to define your personality? Your experience in this existence in this universe/multiverse? This is your challenge. I will start with the photo that defines my personality/experience in this world...
  30. kiwaho

    A What is the photon direction in Z-pinch

    In high energy Z-pinch, lots of X-ray emit. Which direction is the highest density of photon radiation?
  31. Supitha

    B 2 questions about the photo electric effect

    How can explain the difference of these red dots? Red line = Green line ?. How to explain it?
  32. dlgoff

    Mini Photo Shoot: Capturing Taekwon Do Moments

    These were taken this evening at my daughter's Taekwon Do school. Not the best quality photos, but interesting.
  33. K

    Use a bubble chamber photo to find collision/decay particles

    Homework Statement Problem #13 on the attached picture (I can't retype a bubble diagram) Homework Equations I honestly have no clue. I know I'm not supposed to say this because I'm supposed to read my textbook first, but this is not covered at all in my textbook, this is a unit my teacher...
  34. A

    Photo Eye Power: Current, Voltage, & Resistance Explained

    I was reading the specs on a photo eye and it states its current consumption 65 mA at 24v 120 mA at 12v both situations end up with roughly 1.56 VA of power...how does it draw more current with less voltage applied. If V=IR, the only way i see it is the resistance of the system must lower...
  35. S

    Do X-Ray Tracks in Photo Film Suggest Quantum Entanglement?

    In Understanding Quantum Mechanics, Ch.1, Sec. 5 Roland Omnes says: ".. hard x-rays can leave straight-line tracks in photographic emulsion and this is strongly reminiscent of a particle trajectory." How can we describe this in terms of the wavefunction / interaction / measurement paradigm? Is...
  36. Andy Resnick

    Witness the Majesty of the Ring Nebula: 100% Crop & (Nearly) Full Frame

    And lo, after 40 days and 40 nights of rain, a ball of fire in the sky did appear, and after it, a shimmering black velvet curtain of night. Ring nebula: 100% crop and (nearly) full frame: Deets: 800/5.6, 10s ISO 2000 exposures (total integration time 56 minutes). This is the first time...
  37. F

    Finding lens diameter - German physics task

    Hey everybody, I'm right now trying to solve a question I found in a German physics competition 2006 concerning the diameter of a thin camera lens. I'm not able to find a solution, since there is basically nothing given. Here the task (I underlined phrases which might be important): A ruler...
  38. Imager

    Invariant mass of a photon changes - from Wiki

    I'm reading the Wiki article below to say the invariant mass of photons in an expanding volume of space will decrease. I thought invariant mass of a photon was always zero and the energy of photon changed due to the expansion of space. So where did I go wrong? Quote from Wiki General...
  39. mss90

    How Is Maximum Kinetic Energy Calculated in the Photoelectric Effect?

    Homework Statement A magnesium surface has a work.func of 3.68eV. El.mag. waves with wavelenght of 215nm strike the surface and eject electrons. Find the max Ek of the ejected electrons in eV. Homework Equations E=Ek-W <=> Ek=(hc/lambda) - W The Attempt at a Solution I convert eV to J and nm...
  40. Andy Resnick

    Can You Spot All the Galaxies in This Virgo Supercluster Photo?

    Virgo is favorably located right now (for me)- my goal for the next month or two is to stitch together a bunch of image stacks to get the entire region. Here's one 'frame' from last night, showing M84, M86, The Eyes, NGC 4388, 4402, 4461, 4458, 4477, 4459... you get the idea.
  41. Greg Bernhardt

    Earth's Beauty: Showcasing a Favorite Photo

    Post one of your favorite Earth photos
  42. Andy Resnick

    M51 Photo: 1 Hour Total Integration @ 800/5.6, ISO 2000

    And lo, after 8 days of rain, the night sky did appeareth: 1 hour total integration time@ 800/5.6, ISO 2000.
  43. M

    A constant part of a photo taken

    Homework Statement (56th Polish Olympiad in Physics, II stage) A photographer has a camera with a lens of focal ##f## with can be set to a value from the interval ##[f_{min}, f_{max}]##. The diameter of the diaphragm is ##d##. The photographer wants to make a photo of a friend so that the...
  44. Andy Resnick

    Is the Hubble Telescope Smiling at a Gravitational Lens?

    Story at: http://spaceref.com/astronomy/hubble-sees-a-smiling-gravitational-lens.html
  45. davenn

    What caused this mysterious A-Bomb sprite over the Caribbean?

    hi guys Had to share this with you ... This is amazing, have never seen anything like this before in a lightning discharge ( nor has my mate who photo'ed it) My fellow storm chaser Michael, from NE NSW State of Australia took this photo a few days or so ago now a closeup Now tell me that...
  46. B

    Sizing wires for a photo flash

    Hi all. Please pardon the amateurish question! My hobby is constructing camera traps which I use to photograph wildlife, using small "point-and-shoot" compact cameras. Currently I am working on a project that involves removing the flash unit from the camera proper and installing it...
  47. E

    Finding duplicate photos on large photo galleries?

    I was wondering if there is there any kind of program that identifies duplicate photos in large galleries saved on your computer? I've got several galleries that contain more than 1,000 photos and I'd like to delete any and all duplicates. It's extremely difficult to do this manually.
  48. Spinnor

    "Planet formation captured in photo"

    From BBC news, http://www.bbc.com/news/science-environment-29932609# "The clearest ever image of planets forming around an infant star has been taken by the Alma radio telescope. In a vast disc of dust and gas, dark rings are clearly visible: gaps in the cloud, swept clear by brand new...
  49. U

    What are Einstein's 3 postulates for Photo electric effect?

    There are certain conclusions that can be explained by quantum physics about the photoelectric effect: 1) photoelectrons only emitted if frequency>threshold frequency and hence energy of photon> work function 2)Increasing intensity increases no. of photons (and thus photoelectrons provided f>f0...