Originally posted by Chaoron Will I experience the same perspective (roughly), or just the distorsion of the further/nearer objects in the scene?
Steve has it nailed, and hopefully his images will help. Perspective has *absolutely nothing* to do with focal length. You can take a picture of a person with a 35mm or 50mm or 70mm and the perspective is *exactly* the same. Cropping the 35mm image would produce an image indistinguishable from the 50 or 70 (assuming you got DOF to match).
Quote: I think my moving changes the perspective, but the 'how much' is still based on the focal length.
Again, no way can focal length be related. Take two steps forward, repeat the above experiment - again, the images will be *completely* indistinguishable once cropped. Your moving is what changed the perspective, and the degree to which it changed has *nothing* to do with focal length.
Quote: I am just asking about the difference between the APS-C and FF in the perspective (and not FOV).
There are none. The only differences are in FOV. A 28mm lens produces a narrow FOV on APS-C than on FF, but perspective is *identical*, and both of these are *identical* to the perspective you'd get with an 18mm lens, 24, 50, 70, or 135.
Now, *because* of the FOV differences between APS-C and FF, or between different focal lengths, that encourages you to change position accordingly. that is, taking a picture of a person with a 35mm lens on FF, you might try to stand real close to get them to fill the frame. Whereas with APS-C, you might take a step or two backward. that will of course alter perspective. But it's not the focal length or the size of the sensor that did it - it was your feet.