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The crop factor is a linear factor. Your shots illustrate it well.
Almost always the reference is with respect to the "full-frame" 36 x 24 mm film ("35mm" film) or sensor.
So the first one, the 5DII, has a 36 x 24 mm sensor and a crop factor of 1.0. The second one is has a crop factor of 1.3 and the third of 1.6. That means that 36 and 24 divided by 1.6 yields 22.5 x 15 mm approximately.
You have to multiply the crop factor by itself to get the effect on MegaPixels, because they cover an area. So if you have a 20 MPx crop factor camera, you'd have to have 1.6 x 1.6 x 20 MPx in full-frame to crop out the same number of MPx. That would be 2.56 x 20 = 51 MPx.
You can also compute the other way: if you crop a 20 MPx full-frame sensor to match the 1.6x crop, you have to divide by 1.6 squared = 2.56. So 20 / 2.56 = 7.8 MPx or not much resolution.
To approximate the crop, you can multiply or divide the focal length by the crop factor. So to equal the composition of the 500mm on the crop factor, you have to have a 500 x 1.6 = 800mm lens. Or to get the same angle of view on the crop factor as the 500mm on the full-frame, you have to mount a 500 / 1.6 = 312 or 300mm lens onto the crop factor.
You can't shift your position to compensate for the crop factor because that would change the perspective (making a different composition and therefore different photograph) or it would scare the cat.
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