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  • 2.88x

    (36^2 + 24^2)^0.5 / (12.48^2 + 7.02^2)^0.5 = 3.022

    Where did the 2.88x number come from? Or, alternately, where did the 12.48mm x 7.02mm number come from? Only one or the other is correct.

  • #2
    where are you talking 24x36 from? S35 is 24.9x18.66.

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    • #3
      The "crop factor" is expressed relative to FF35 (36x24), not S35.

      S35 to PCC would be 2.173x.
      Last edited by Lee Saxon; 08-21-2013, 01:17 PM.

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      • #4
        Ooops, I just figured out the answer to my own question. 2.88x is the horizontal, not diagonal, crop factor. 36 / 12.48 = 2.885

        Diagonal is more commonly used, though typically in comparing formats that have a similar aspect ratio, like FF35 and APS-C. With the much wider format of the PCC, using horizontal does arguably make more sense.

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        • #5
          in general "crop factor" is a stupid term, because there is no crop of the sensor. It might make sense with RED 2 and 4K, where in 2K only a part of the sensor is scanned, but this is not the case with Pocket Cinema. And of course FOV on S16 size sensor is going to be different from S35 or MFT size with the same focal length of the lens. But there is no cropping or change in focal length.

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          • #6
            When "crop factor" is used talking in reference to a larger sensor format it makes perfect sense. Sensor A has 2.885 crop factor of Sensor B, It has become such common nomenclature that we all assume the reference is understood without explaining it.
            Nick Colombini
            Cinematographer|Editor|Filmmaker
            http://www.nickcolombini.com

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            • #7
              I don't think the Red example is really all that different. Whether you're putting a lens on a smaller format camera or setting your camera to record in a smaller-than-usual format, you're opting to use only part the image your lens is projecting.

              I do think Nick is exaggerating somewhat the extent to which the term is generally understood, especially with new photographers. It causes a lot of confusion. A lot of people think there's some sort of optical conversion involved, that smaller-sensor ("crop sensor" they sometimes call them, a far more problematic term than "crop factor") cameras somehow function like the SpeedBooster. Tons of threads out there explaining that away.

              That said, going back to my first paragraph, I can't really think of anything better :/

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              • #8
                We assume it is understood. Are we perpetuating the confusion!? http://en.wikipedia.org/wiki/Crop_factor
                Nick Colombini
                Cinematographer|Editor|Filmmaker
                http://www.nickcolombini.com

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