Interesting focus problem on a Canon 400/2.8

jheftijhefti Registered Users Posts: 734 Major grins
edited November 9, 2011 in Cameras
OK, here's a quiz: For the last few shoots I have noticed that my Canon 400/2.8 was sporadically giving me soft images--sometimes really OOF! The last shoot the problem was really weird in that the focal plane did not appear to be parallel to the sensor, as if I were tilt-shifting! A player running towards me might have the knees in perfect focus but the face out of focus. I got this effect on all of my bodies (5D2, 1D4, etc...) A couple of days ago I finally solved the mystery, and it took me about one minute to fix it.

Any guesses? I had never seen this problem before!
http://johnhefti.com/

Comments

  • ziggy53ziggy53 Super Moderators Posts: 24,119 moderator
    edited November 9, 2011
    I would guess a loose front or rear element/group?
    ziggy53
    Moderator of the Cameras and Accessories forums
  • jheftijhefti Registered Users Posts: 734 Major grins
    edited November 9, 2011
    ziggy53 wrote: »
    I would guess a loose front or rear element/group?

    Nope--even simpler than that!
    http://johnhefti.com/
  • QarikQarik Registered Users Posts: 4,959 Major grins
    edited November 9, 2011
    front filter was loose somehow?
    D700, D600
    14-24 24-70 70-200mm (vr2)
    85 and 50 1.4
    45 PC and sb910 x2
    http://www.danielkimphotography.com
  • QarikQarik Registered Users Posts: 4,959 Major grins
    edited November 9, 2011
    there was something obstructing the mounting between the lens and camera body casuing your lens to tile off axis somehow
    D700, D600
    14-24 24-70 70-200mm (vr2)
    85 and 50 1.4
    45 PC and sb910 x2
    http://www.danielkimphotography.com
  • ThatCanonGuyThatCanonGuy Registered Users Posts: 1,778 Major grins
    edited November 9, 2011
    The drop-in filter was loose?
  • jheftijhefti Registered Users Posts: 734 Major grins
    edited November 9, 2011
    Qarik wrote: »
    there was something obstructing the mounting between the lens and camera body casuing your lens to tile off axis somehow

    Ooooo, getting close!!
    http://johnhefti.com/
  • ziggy53ziggy53 Super Moderators Posts: 24,119 moderator
    edited November 9, 2011
    jhefti wrote: »
    Ooooo, getting close!!

    Aha, the screws holding the camera side lens mount were loose.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • jheftijhefti Registered Users Posts: 734 Major grins
    edited November 9, 2011
    ziggy53 wrote: »
    Aha, the screws holding the camera side lens mount were loose.

    ...and we have a winner!!!!!!!!!!!!!

    I was getting so frustrated that I almost sent the lens off to Canon. I would have felt really stupid had I done so! One screw was completely out, and several others were loose. Can't believe I didn't notice this until I couldn't even attach a body to it!
    http://johnhefti.com/
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