How big a lens to flex a plastic body?

Discussion in 'Digital SLR' started by RichA, Jul 1, 2007.

  1. RichA

    RichA Guest

    Someone came into a camera store the other day and traded in his D80
    for a D200. He said he did it because the large zoom (heavy) he was
    using was flexing the body outward slightly at the mount. I think it
    was the 80-400mm. The sales person asked if he was supporting the
    lens with his hand. He said he was but still felt that the body was
    being flexed slightly when he moved fast to shoot sports subjects. The
    D80 body appears to be about as robust as a plastic body is right
    now. Which make me wonder about the dynamics of longer heavy zooms
    used on lesser bodies than the D80. Obviously, given the speed and
    focal length of these lenses, it wouldn't take much misalignment to
    effect focus on the sensor.
     
    RichA, Jul 1, 2007
    #1
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  2. Hmmm, but the D80 has a metal chassis as well as a metal lens mount. I would
    assume (although I didn't check), that the lens mount connects directly to
    the chassis.

    jue
     
    Jürgen Exner, Jul 1, 2007
    #2
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  3. RichA

    Robert Coe Guest

    : Someone came into a camera store the other day and traded in his D80
    : for a D200. He said he did it because the large zoom (heavy) he was
    : using was flexing the body outward slightly at the mount. I think it
    : was the 80-400mm. The sales person asked if he was supporting the
    : lens with his hand. He said he was but still felt that the body was
    : being flexed slightly when he moved fast to shoot sports subjects. The
    : D80 body appears to be about as robust as a plastic body is right
    : now. Which make me wonder about the dynamics of longer heavy zooms
    : used on lesser bodies than the D80. Obviously, given the speed and
    : focal length of these lenses, it wouldn't take much misalignment to
    : effect focus on the sensor.

    I'm neither a metallurgist nor an organic chemist, but my impression is that
    modern polycarbonate plastics are at least as stiff as most metals. If you use
    a huge, heavy lens with any camera body and don't support it correctly, you
    have to expect whatever happens.

    Bob
     
    Robert Coe, Jul 1, 2007
    #3
  4. Never, ever, fly in a Boeing 787 if you are afraid of plastic. It has a
    plastic body.

    Owl
     
    Astigmatic Owl, Jul 1, 2007
    #4
  5. If it makes him feel good and he has the money, Why not. In real life
    I can't see it being a problem. However I tend to look at results and if I
    am happy with them, I don't see problems. Some people spend more time
    looking for problems than practicing their art. Maybe they don't know
    photography is more art than science?
     
    Joseph Meehan, Jul 1, 2007
    #5
  6. RichA

    G.T. Guest

    Was it your son DickA? I., mean, come on.

    Greg
     
    G.T., Jul 1, 2007
    #6

  7. Bro, the thought of a fertile Dick[A] is too horrifying to contemplate.
     
    â–€Slack, Jul 1, 2007
    #7
  8. RichA

    dwight Guest

    Oh, no! Oh me, oh my... Whatever shall I do?

    I just ordered the 100-400mm lens for a test drive on my shoddy, inferior,
    plastic Rebel XT. No doubt, the camera will be destroyed over the next two
    weeks.

    Damn. Wish I'd known about this before.

    dwight
     
    dwight, Jul 1, 2007
    #8
  9. RichA

    G.T. Guest

    Be carefull, that Rebel XT may blow up in your face as soon as you attach
    that lens. The Rebel XT is certified for only 6 oz and under plastic
    lenses.

    Greg
     
    G.T., Jul 1, 2007
    #9
  10. RichA

    Charles Guest

    RichA obsesses a lot here. Just plonk him.
     
    Charles, Jul 1, 2007
    #10
  11. RichA

    King Sardon Guest

    Don't complain. Now you can do swings and tilts.

    KS
     
    King Sardon, Jul 1, 2007
    #11
  12. RichA

    Paul Furman Guest

    LOL
    rubber-body camera-baby
    :)
     
    Paul Furman, Jul 1, 2007
    #12
  13. RichA

    Bill Funk Guest

    If the salesperson was worth his salt, he definitely sold a D200 that
    day.
    The "Someone" in this story is, though, a dolt.

    --
    THIS IS A SIG LINE; NOT TO BE TAKEN SERIOUSLY!

    The White House announced that President Bush
    will meet with Mexican President Felipe Calderon
    next month. They have to discuss the growing
    problem of illegal immigration. The two presidents
    agreed to meet in Mexico's capital city, Los Angeles.
     
    Bill Funk, Jul 2, 2007
    #13
  14. RichA

    Watcher Guest

    RichA is waiting for the Zenit B Digital. Not only is it metal, but it
    has EMP proof vacuum tubes.

    ;)
     
    Watcher, Jul 2, 2007
    #14
  15. RichA

    Guest Guest

    He can save money and not buy a Lensbaby ®

    Just flex that funky body..
     
    Guest, Jul 2, 2007
    #15
  16. RichA

    RichA Guest

    Unreinforced polycarbonate? I don't think so. In addition, like the
    tail in the Airbus monster coming online, it is heavily reinforced
    with massive carbon fibre ribs, much larger in thickness than
    traditional aluminum airframe designs. The tail in the new Airbus is
    something like 7 stories tall. I sure hope the glue holds...

    http://www.popularmechanics.com/technology/transportation/3493516.html

    BODY Composite fibers--carbon graphite, held together by epoxy--
    account for 50 percent of the overall fuselage, versus the 9 percent
    in the 777, making the 787 lighter and stronger than aluminum-body
    aircraft.
     
    RichA, Jul 2, 2007
    #16
  17. RichA

    RichA Guest

    Remember all the error 99 problems that people attributed to "dirty
    contacts?" You had people wiping off the contacts, in many instances
    no dirt was present and the camera was new. It is possible some kind
    of body flexture problem produced the contact problem. Canon vaguely
    attributed it in some cases to lens-body "mismatches" but it doesn't
    explain why it would happen with a Canon lens on a Canon body, only an
    aftermarket lens.
     
    RichA, Jul 2, 2007
    #17
  18. RichA

    frederick Guest

    There's more than a few Error 99 problems being reported with 1dIII.
    It's disgusting that Canon would use cheap plastic in a $5000 camera.
     
    frederick, Jul 2, 2007
    #18
  19. RichA

    Pete D Guest

    Maybe he was just mistaken, last time I looked most plastic bodies were just
    that and nothing more, stainless steel chassis with the plastic just there
    to cover the chassis.
     
    Pete D, Jul 2, 2007
    #19
  20. RichA

    Pete D Guest

    Similar to camera construction, nice strong inner frame, light plastic
    cover.
     
    Pete D, Jul 2, 2007
    #20
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