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Thread: 85mm round up

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  1. #15
    Join Date
    Feb 2006
    Des Plaines, IL

    APS-C sensor issues

    Whatever the focal length says on the lens, with an APS-C sensor camera, you have to multiply it by 1.5x (for SONY) to get the effective frame size of what your would see on a Full Frame camera.

    Basically, the 17-50mm f/2.8 lens on an APS-C camera turns out about the same images as the 28-75mm f/2.8 lens on the Full Frame.

    In a nutshell, here is the image circle from the back of the lens and how it relates to the two different sensors.

    Because the APS-C only sees a smaller part of the image circle, it looks like you have effectively zoomed in on the subject. Remember, this applies only to using the same lens on both cameras. The 17-50mm f/2.8 (APS-c only lens) was developed to counter this issue on APS-C sensors. It offers "equivalent" images that you would see with operating a 28-75mm f/2.8 on the Full Frame or 35mm-film body.

    Hope that makes some sense. OMG ... it this horse dead, yet? We are so far off my topic ...
    Last edited by DonSchap; 05-08-2011 at 09:41 PM.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

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