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Thread: What are the protocols used by Canon in lens mount?

  1. #1

    Default What are the protocols used by Canon in lens mount?

    The ways camera communicates with the lens, what are the protocols?
    Is it feasible/economical to make adaptors which can connect Canon lens to
    Nikon, KM, Pentax, etc? I make a living in electronics.

  2. #2
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    Default Re: What are the protocols used by Canon in lens mount?

    Quote Originally Posted by dRebelXT
    The ways camera communicates with the lens, what are the protocols?
    Is it feasible/economical to make adaptors which can connect Canon lens to
    Nikon, KM, Pentax, etc? I make a living in electronics.
    if they let u know, it wouldn't be proprietary... if hack it, it would be infringement of copyright...
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  3. #3

    Default Re: What are the protocols used by Canon in lens mount?

    Quote Originally Posted by Del_CtrlnoAlt
    if they let u know, it wouldn't be proprietary... if hack it, it would be infringement of copyright...
    OIC, they are proprietary no wonder.

  4. #4

    Default Re: What are the protocols used by Canon in lens mount?

    Quote Originally Posted by dRebelXT
    The ways camera communicates with the lens, what are the protocols?
    Is it feasible/economical to make adaptors which can connect Canon lens to
    Nikon, KM, Pentax, etc? I make a living in electronics.
    It will not be that difficult to find out the communication protocol, you will probably just need a logic analyser and an oscilloscope as some of the contacts may be carrying analog signals. But even if you can interface the electronics, it may not be that feasible to interface the mechanical and optical aspects.

    1) The electronic contacts sits on the lens mount itself and if you would like to put in a non invasive adaptor, then you will need some space and that would mess up the optics unless you put in a piece of optics to correct the additional distance. eg, M42 adapters.

    2) Some lenses are electronically driven while some are a combination. For example, Canon's EOS lenses have an electronic aperture control and the AF motor is in the lens. For Nikon, the aperture is mechanically controlled. With the exception of the AF-S lenses which uses linear ultrasonic motor, the AF motor is built into the body and is coupled by a mechanical shaft to turn the focusing in the lens.

    What is more feasible would be the interface for electronic flashes.

  5. #5

    Default Re: What are the protocols used by Canon in lens mount?

    Quote Originally Posted by Del_CtrlnoAlt
    if they let u know, it wouldn't be proprietary... if hack it, it would be infringement of copyright...
    Well, if you want to use it you can always licence from the original manufacturer.

  6. #6
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    Default Re: What are the protocols used by Canon in lens mount?

    Quote Originally Posted by lsisaxon
    Well, if you want to use it you can always licence from the original manufacturer.
    actually i know who have, just dunno which 1 of them... maybe can try calling sigma, tokina or tamron...
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  7. #7
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    Default Re: What are the protocols used by Canon in lens mount?

    actually, i think this will soon become free information as it was patented sometime back in the 80s when the EF mount first came out. Assuming a patent of 20yrs, which is the norm, it should be out in the public domain soon.

  8. #8

    Default Re: What are the protocols used by Canon in lens mount?

    Found a website which may be useful.. I haven't browse through it yet.
    http://www.birger.com/Merchant2/merc...een=ef232_home

    This site http://vsd.pennnet.com/Articles/Arti...ICLE_ID=236708 mentions that those 3rd party lens makers like Sigma, Tokina and Tamron all reverse engineered the EF lens interface because Canon refused to license.
    Last edited by lsisaxon; 17th January 2006 at 05:48 PM.

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