Should 4/3 lenses be half the size of full frame lenses?

Discussion in 'Digital Cameras' started by bob, Jun 13, 2011.

  1. Huh?
    - A dust speck of the same size will cover 2x more pixels on the 12 MPix
    - Choosing the same framing, image details will cover 2x more pixels per
    same-sized detail on the 12 MPix sensor.

    Thus at 100% pixel view, details and dust on the 6 MPix sensor
    will be smaller.
    At least to my understanding.

    Maybe I'm just misreading you ...
    Sorry, I don't get it.

    Wolfgang Weisselberg, Jun 22, 2011
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  2. I disagree. If one is evaluating several options by some
    measurements/standards/weighting, then two options are equivalent when
    the measurements/standards/weighting returns the same result.

    This does not imply they are identical, because if they were
    identical, they would be more than just equivalent --- and wouldn't
    be two separate options.

    Example: Time needed to get to work.
    If using public transport and using the car (including searching
    for parking space and walking from there to work) take the same
    time, they are equivalent in their time need. That doesn't imply
    they are identical, cost the same, have the same ecological
    footprint, are like in their susceptibility to strikes and/or
    traffic jams and/or bad weather, etc.
    They don't produce *identical* images, but unless the noise *does*
    have a *relevant* (as in visible and noticeable) impact on the
    final product, they are very much equivalent.

    See also Merriam-Webster's reliable book:

    Definition of EQUIVALENT
    1 : equal in force, amount, or value; also : equal in area or
    volume but not superposable <a square equivalent to a triangle>
    2 a : like in signification or import
    b : having logical equivalence <equivalent statements>
    3 : corresponding or virtually identical especially in effect
    or function
    4 : obsolete : equal in might or authority
    5 : having the same chemical combining capacity <equivalent
    quantities of two elements>
    6 a : having the same solution set <equivalent equations>
    b : capable of being placed in one-to-one correspondence
    <equivalent sets>
    c : related by an equivalence relation

    Note 1 --- NOT SUPERPOSABLE --- not identical.
    Note 5 --- different elements --- not identical.
    Note 6a --- same solution set --- doesn't mean identical equations,
    for example.

    Definition of IDENTICAL
    1 : being the same : selfsame <the identical place we stopped before>
    2 : having such close resemblance as to be essentially the same <identical
    hats> —often used with to or with
    3 a : having the same cause or origin <identical infections>
    b : monozygotic

    Wolfgang Weisselberg, Jun 22, 2011
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  3. Nope.

    Take an 8 MPix 1.6x crop sensor and a 21 MPix 35mm sensor ---
    and crop the 21 MPix sensor to 1.6x somewhere between sensor
    exposure and final output.

    They're not only equivalent, they're *identical*.
    And a triangle can be equivalent in size to a square. Too.

    Wolfgang Weisselberg, Jun 22, 2011
  4. Wolfgang Weisselberg, Jun 22, 2011
  5. bob

    tony cooper Guest

    tony cooper, Jun 22, 2011
  6. bob

    Paul Furman Guest

    It wouldn't make sense for photographic purposes, just a demonstration
    of the idea that there are always tradeoffs. Larger sensors can do great
    low noise and achieve more resolution but they have less DOF and so
    require longer exposures to balance that out. Bump the ISO and you've
    got the exposure short again but may lose resolution to diffraction and
    introduced more noise.

    You could design a compact sensor with super-low ISO and super fast
    lenses but it wouldn't make sense. Cheaper to use a larger format for
    that particular need. But not for every need, otherwise all
    photographers would still use large format view cameras. The do still,
    when it makes sense like for extra-large prints of static landscapes.
    Paul Furman, Jun 23, 2011
  7. bob

    Paul Furman Guest

    Yes a bright image have less noise. You can use soft studio lighting
    which doesn't have harsh highlights to blow out (or grainy dark shadows)
    and get great quality with a smaller sensor. That lets you overexpose
    and dial it down in post to get effectively a lower ISO.

    Or you can take a hundred short frames and stack them to avoid blowout
    and get all the photons you need, as in astro shooting.
    Paul Furman, Jun 23, 2011
  8. bob

    Paul Furman Guest

    You would gain selective focus and evade diffraction, allowing higher
    resolution (in theory... or when comparing stopped down operation).
    Paul Furman, Jun 23, 2011
  9. bob

    Paul Furman Guest

    Equivalent DOF and equivalent total photon count for the scene, and back
    to the OP's question; equivalent lens size, actually larger because
    you'd have to add the converter.
    Paul Furman, Jun 23, 2011
  10. It'll cover the same physical size, and when I display the image
    on my screen at any given physical size, will be equally big.

    All of which is a side issue, as I think we've agreed.
    David Dyer-Bennet, Jun 23, 2011
  11. Yes, probably. But still gain nothing in the number of photons for a given
    Neil Harrington, Jun 23, 2011
  12. bob

    Paul Furman Guest

    Meaning the same enlargement where the smaller sensor makes a smaller
    image on your screen?
    Paul Furman, Jun 23, 2011
  13. bob

    John Turco Guest

    And, >you're< proving (for the millionth time) that you're a liar,

    I >did< claim to have kill-filed David Taylor, right?
    Yeah, maybe David should make the trek from Scotlamd to England,
    and visit your cozy camera shop. Then, you could use your "hard
    sell" tactics on him, and unload lots of "professional" gear.

    Oh, hold on...does Fisher-Price even make DSLR equipment?
    John Turco, Jun 30, 2011
  14. bob

    John Turco Guest

    You'd meant Roger N. Clark, I'm sure.
    John Turco, Jun 30, 2011
  15. bob

    John Turco Guest

    Hey, "dj_nme" -- why does every one of your sentences, always begin on a
    new line?

    (On the other hand, "nospam" never uses uppercase letters.)
    John Turco, Jun 30, 2011
  16. bob

    John Turco Guest

    <edited for brevity>

    Nor brain science.
    John Turco, Jun 30, 2011
  17. bob

    John Turco Guest

    "Don't Raise the Bridge, Lower the River" (1968) is a Jerry Lewis movie
    John Turco, Jun 30, 2011
  18. Yes, of course!

    Somehow the "clark" and "vision" became combined to form the new


    Thanks, John.
    David J Taylor, Jun 30, 2011
  19. You mean

    And you didn't visit the historic city centre *right outside the
    hotel*, didn't visit the cathedral *half a stone throw away*[1],
    didn't walk down to the Rhine (3 minutes walk, at most), didn't
    go to one of the many pubs there on the banks of the Rhine,
    didn't visit a brewpub and had 'typical Cologne' food (in the
    old town), ... tons of chances to see the Kölschstangen in use.
    Even the English wikipedia knows them:

    And you might have observed the Köbesse ...öbes

    Must have been a very interesting room if you just stayed in.


    [1] just across the Bahnhofsvorplatz and up the (then much wider)
    Wolfgang Weisselberg, Jul 1, 2011
  20. Did you mean "12MP sensor" here? That would explain everything ...
    We do. Just trying to understand where what you meant and what
    I understood diverged from each other ... or if I am just plain
    wrong on a point in my mental model of sensors and enlargements.

    Wolfgang Weisselberg, Jul 3, 2011
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