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Thread: Focus by wire means when you rotate the focus ring,

  1. #1

    Question Focus by wire means when you rotate the focus ring,

    some electrical signals detect the rotation and move the lens units, am I right?

    As a result, some latency is expected comparing to DSLR lens.


  2. #2

    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by dRebelXT View Post
    some electrical signals detect the rotation and move the lens units, am I right?

    As a result, some latency is expected comparing to DSLR lens.

    Yeah it is correct. Some DSLR lenses also use focus by wire. An example is the 85 f1.2L.

  3. #3
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    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by sweat100 View Post
    Yeah it is correct. Some DSLR lenses also use focus by wire. An example is the 85 f1.2L.
    Which brand?

    Regards,
    Arto.

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    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by dRebelXT View Post
    some electrical signals detect the rotation and move the lens units, am I right?

    As a result, some latency is expected comparing to DSLR lens.

    The manufacturer replace focusing ring into something like switch (or variable resistor) to detect turn left or right (and also how much you turn it, for slow focusing or fast focusing). Then the signal will go to the auto-focus motor to set the lens focus distance.

    Some may feel "loose the touch" when using focus by wire.

    Regards,
    Arto.

  5. #5

    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by Artosoft View Post
    Which brand?

    Regards,
    Arto.
    The canon 85mm f1.2L.

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    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by Artosoft View Post
    Which brand?

    Regards,
    Arto.
    I think only Canon labels 'L' to their lenses..
    “How fortunate for leaders that men do not think.” - Adolf Hitler

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    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by Artosoft View Post
    The manufacturer replace focusing ring into something like switch (or variable resistor) to detect turn left or right (and also how much you turn it, for slow focusing or fast focusing). Then the signal will go to the auto-focus motor to set the lens focus distance.

    Some may feel "loose the touch" when using focus by wire.

    Regards,
    Arto.
    usually it's done neither by switch nor variable sensor. Optical systems are preferred.
    “How fortunate for leaders that men do not think.” - Adolf Hitler

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    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by yanyewkay View Post
    usually it's done neither by switch nor variable sensor. Optical systems are preferred.
    "Something like switch" can mean anything that behave like that .

    Regards,
    Arto.

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    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by sweat100 View Post
    The canon 85mm f1.2L.
    Thanks!

    I though only olympus with e system do focus by wire... Learn new thing today .

    Regards,
    Arto.

  10. #10

    Default Re: Focus by wire means when you rotate the focus ring,

    Quote Originally Posted by yanyewkay View Post
    usually it's done neither by switch nor variable sensor. Optical systems are preferred.
    paiseh, althou i use Oly E sys, i still dun know how this focus by wire works.

    my impression is its working principle is something like that of power steering in cars. kind of using electro magnetic sensing.

    if i'm not mistaken video cams & some P&S (sony F505 F707 F818?) also use this focus by wire technique to focus.

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    Default Re: Focus by wire means when you rotate the focus ring,

    The Canon super-telephotos at f/2.8 and f/4 are using it too. Eg. 300/2.8, 400/2.8, 500/4 and 600/4. Not sure about 1200/5.6 though.

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