Distance from back of lens to sensor?

Discussion in 'Digital Photography' started by Kingsly, Dec 17, 2007.

  1. Kingsly macrumors 68040


    On a Canon EF mount camera, how far is it from the back of the lens to the image sensor (or that flappy stuff they call "film" :rolleyes:)?

    I'm making a homebrew digital cine rig and need to get my measurements for the gorund glass distance right!
  2. astrostu macrumors 6502

    Feb 15, 2007
    On the top of your camera there should be an indicator of where the sensor plane is. On mine (350D), it looks like the Greek letter phi and is to the left of the built-in flash.
  3. Kingsly thread starter macrumors 68040


    Wow, my eyeballed measurments were nearly correct! 1 3/4".

    thanks! :)
  4. Big-TDI-Guy macrumors 68030


    Jan 11, 2007
    Are we talking about F-lengths here?

    Not an SLR person (yet) but that data should be readily available on the Lens and/or the camera too.
  5. ChrisBrightwell macrumors 68020


    Apr 5, 2004
    Huntsville, AL
  6. astrostu macrumors 6502

    Feb 15, 2007
    1.75" = 44.45 mm. I'm guessing Kingsly will not be able to measure to the sub-mm scale so this difference won't affect it too much.
  7. Kingsly thread starter macrumors 68040


    Thankfully there seems to be a bit of range in the back-focus. I was off by 1mm in my final product, but I can just compensate with the lens (DOF charts won't be accurate though... :()

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