Zoom Question

Discussion in 'Beyond the Basics' started by Stranger, Dec 8, 2007.

  1. Stranger

    Stranger TPF Noob!

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    On a digital body (lets say 1.5 crop factor). What is the translation to P&S optical zoom and at what mm is the hhuman eye?

    I get these questions so often at work and never have an answer.
     
  2. Alex_B

    Alex_B No longer a newbie, moving up!

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    first of all:
    when you read something lie 3x optical zoom, that only refers to the ratio between shortest and longest focal lengths. it has no relation to absolute numbers


    a 3x optical could be 1mm - 3mm or 12mm - 35mm or 100mm-300mm

    The human eye ... or better what we would consider a natural perspective is close to 50mm on 35mm medium (1.0 crop). on a smaller medium it would be a shorter focal length (35mm-ish on a 1.6 crop) and on a p&s i would be way shorter since their sensor is way smaller (exact numbers depend on the p&s camera here)
     
  3. Sideburns

    Sideburns TPF Noob!

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    people asking "how many X zoom is it?" don't know what's goin on...cause a camera could have 5X zoom and be able to bring things closer/bigger than a 12X zoom...it all depends on what the widest angle is.

    Also, a standard lens on a 35mm is 50mm...so the camera should say "50mm equivalent" or something...(or be inside the range that is given)...
     
  4. Stranger

    Stranger TPF Noob!

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    Good stuff, i never knew that about the zooms... on majority of the tests ive ran they seemed to start at about the same spot so i thought they were direct numbers.

    Thanks a lot.
     
  5. Conan

    Conan TPF Noob!

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    Not to go against what's being said here but more for reference:
    On my Nikon FM2 (35mm film) the 'natural perspective' as it had been stated previously is 55mm. Of course that's just to my eye and as close as I could tell. Kyle
     
  6. Alex_B

    Alex_B No longer a newbie, moving up!

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    as far as i know this is not sharply defined anyway ... in the end it also depends on the print size, and the distance you are looking at the print
     
  7. Sideburns

    Sideburns TPF Noob!

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    Does it not have more to do with the angle of view than anything else?
     
  8. avcabob

    avcabob TPF Noob!

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    I always thought 50mm was "normal" because if you look through the camera (at 50mm) with one eye and leave the other eye open, what's seen with both eye's are about the same.
     
  9. Alex_B

    Alex_B No longer a newbie, moving up!

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    the actual angle of view in terms of what you see in colour and sharp is extremely shallow. human vision builds up the image in your brain by wandering around in the scene. depending on how concentrated on the subject you are, your effective "angle of view" can vary alot! so just comparing this number makes no sense strictly speaking.


    I will try to illustrate this with an example: take a large ultra-wide angle print. say 2m x 2m. if you look at it from 2m distance, than it appears rather wide angle. if however you stand very close and look at it from 50 cm or less, then it will not appear like a wide angle shot.


    hence my comment on printing size and viewing distance.

    of course we have a certain habit of choosing the distance according to the print size in always the same manner. However, if we are forced into a certain distance (by the way an image is displayed), then things are different.
     
  10. Sideburns

    Sideburns TPF Noob!

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    makes sense to me.
     

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