Perspective: It's where you stand and not the focal length!

Discussion in 'Casual Photo Conversations' started by beegeedee, Oct 1, 2017.

  1. Are you aware that if you stand in the same spot, shoot with different focal lengths and then crop, that the perspective is always the same? (Peace Camera - Raleigh, North Carolina
    [​IMG]picture_44 by BG Day, on Flickr
     
    I_Kelly and KenPapai like this.
  2. James G. Dainis

    James G. Dainis Moderator

    I think most people who have been into photography for a while have been told that. If one says, "Use a telephoto lens for a more compressed look" someone else is sure to come in with, "The telephoto doesn't compress anything; the perspective stays the same when shooting from the same spot." Of course it is easier to use a telephoto lens taking a shot of a city street from a block away to make the pedestrians all look crowded together than to use a normal lens and then crop out about 1/8th of the film or sensor. And, how would you do that if you were shooting video and waned to make the pedestrians look crowded together? You would have to use telephoto to get that compressed look.
     
    I_Kelly and beegeedee like this.
  3. William Michael

    William Michael Moderator Staff Member

    Yes, I knew that.

    Cricket Oval made with various Focal Length Lenses Camera does not change position: 16, 20, 35, 70, 100, 135, 200, 300 and 400 -
    UNCROPPED:
    [​IMG]

    ***

    CROPPED:
    [​IMG]

    The topic specifically or related comes up regularly in forums and often contains a form of words which are assumed facts, (often re-spread around the internet) which only exacerbates misunderstanding: for example - in the Beginner Forum [HERE LINK], note the OP states “we know that long lenses compress the elements in the picture; wide angle lenses separates them.”

    The topic also sometimes leads to strong opinions as here [LINK]

    WW
     
    KenPapai and beegeedee like this.
  4. Are you aware that what people (and you?) think/feel they are seeing in a picture is much more important to you when making a picture, than what you can "prove" that they will "be seeing" in that picture? (And how would you prove that, anyway? It's in their mind ... )
     
  5. Very true, and well demonstrated. Surprisingly, there are some cinematographers who mistakenly believe that focal length compresses distance (although this misunderstanding does not affect their skill, so I'm not trying to knock people down just because they made a theoretical mistake). The point is that some myths are very stubborn.

    In fact some scientists make surprising mistakes quite often. And statisticians do, as well. For example, you are not necessarily supposed to multiply probabilities - it depends on the nature of the problem. You may have heard about the case in the UK where a mother was sent to jail for having two kids die of SIDS, one after the other. The chances of one child dying of SIDS is about 1 in 8,000, IIRC. The chance of a second child dying of SIDS is also 1 in 8,000 - not, as you might think, 1 in 64M. The prosecution made the error of multiplying the probabilities, and the defence was too ignorant to know that they had been hoodwinked.

    I'll also mention the Monty Hall problem which not only confused the living daylights out of me when I first heard it, but it also confused some mathematicians.

    Now, if I may offer a nitpick, it's my understanding that perspective does not involve focal length, but it involves the camera position. Move the camera (or rather, the optical axis to a different point in 3D space) and you change perspective. ;-) Of course the common usage of perspective is more inclusive than that, though I don't like it.
     
    KenPapai likes this.
  6. KenPapai and beegeedee like this.
  7. Perception can change dramatically, without changing perspective an iota.

    Words of art only matter to those that practice the art.
     
  8. Good one!
     
    dcstep likes this.
  9. James G. Dainis

    James G. Dainis Moderator

    Karim, that was a timely mention of the Monte Hall problem. Monte Hall passed away three days ago but his legacy will be the problem named after him which confuses people to no end.

    Monty Hall problem - Wikipedia
     
    KenPapai and dcstep like this.
  10. Thanks for the Monty Hall Wiki link.
     
    dcstep likes this.
  11. Here's yet another illustration of the point from the Life Library of Photography volume The Camera. I've edited it slightly to fit the format here:
    Perspective-(Camera-TL)-small.jpg
     
  12. It's true that perspective is all in where you stand.

    At the same time, if you like wide angles it's hard to get around the fact that you can't stand close enough AND get everything you want in the photo to get the desired perspective. That's why I'm now trying to figure out what organ I can sell that will buy a Nikon 14-24mm 2.8 :)

    Also, if you want the classic "portrait" perspective you'd better have your technique down perfectly, have enough resolution/a fine enough grain film, and be using a good lens if you want something that's not a traditional "portrait length" lens.

    BTW, this discussion is also fun to have with regard to depth of field. Many folks relate depth of field to focal length and distance from the subject, but truthfully that simplifies quite nicely to magnification ratio. All else being equal, DOF doesn't change if the magnification ratio is kept constant(of course aperture along with intended print size are the other parts of that equation). It's possible to take a series of photos with different focal lengths where the subject is kept the same size in the frame(thus the same magnification ratio) and with the same aperture the DOF will remain the same although, of course, the perspective will change.
     
    beegeedee likes this.
  13. All we need is one superb 180 degree angle of view non-distorting lens and a camera with very high resolution and we need never use more than one lens to obtain any of the 100s of potential pictures contained within each image.
     
  14. I'll stick to running through water gushing from open fire hydrants on a swelteringly hot New York City summer day for my fun, thanks, lol. :rolleyes:
     

Share This Page