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Thread: The science of in-body image stabilization query

  1. #1
    pwnage101's Avatar
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    The science of in-body image stabilization query

    Sony and Pentax claim that their sensor-shift image stabilization allows for the implementation of such technology even with lenses older than the technology itself. However I have been thinking about it, and do not understand how it can work with every available lens fitted to a given body with stabilization.

    A 0.05 degree camera shake will surely seem more significant on a 100mm lens than a 50mm one, so it calls for a larger sensor shift for compensation. However, what about lenses that do not transmit focal length data to the body? I am in search for a DSLR and I've been keeping an eye on the Pentax K-X. How will this body work with a Pentax-A SMC 50mm f/1.7 that "doesn't digitally transmit focal length data" ?

    Thanks.

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    Have a guess :)

    Re: The science of in-body stabilization query

    For what it's worth, Canon's stated position for avoiding in-camera stabilization is that (paraphrased) "you need different IS characteristics for different lenses" - so at least Canon agree with you

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    pwnage101's Avatar
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    Re: The science of in-body stabilization query

    http://en.wikipedia.org/wiki/Image_s..._Stabilization
    The sensor is moved to maintain the projection of the image onto the image plane, which is a function of the focal length of the lens being used; modern cameras can acquire focal length information from the lens.
    Well, there you have it. I'm right.

    I remember reading somewhere that if you attach a Pentax-A lens onto a Pentax D-SLR, it will recognize that the lens is model A; at least it's a start

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    Terry Tedor's Avatar
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    Re: The science of in-body stabilization query

    If the lens does not transmit focal length information to the body, as you mentioned in your first post, how does the body know what the focal length is?

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    pwnage101's Avatar
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    Re: The science of in-body stabilization query

    BINGO!
    To function properly the camera needs to know the focal length of the lens. If you are using a Pentax DA, D FA, FA J, FA or F lens this information is acquired automatically. For all other lens types you can enter it manually in the menu.
    You simply enter the information manually! I hope this is no different on the Pentax K-X. (k-x is newer than the k200d after all)
    Last edited by pwnage101; 9th February 2010 at 10:43 PM.

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