David G. Healy Posted July 14, 2007 Share Posted July 14, 2007 I sent Chris's study to John Costella for his opinion. He did a quick vector analysis of this and adjacent frames, and assures me that the leaning curb mark appears in other frames and is consistent with panning blur of the background. These factors make understanding Z blurs difficult: ...panning movement of camera (blurs background) ...movement car (blurs car and occupants) ...vertical jiggle of camera (makes erratic blurs) ...combinations of the above (makes complex blurs) Costella made a year-long study of Z-blurs and found that the blurs were manipulated with almost mathematical precision...WITH A FEW EXCEPTIONS which he has previously described. He reiterates his view that the background grass is from a separate film than the foreground, joined at the straight curbline. I must defer to John's superior expertise, though I still do not quite visualize how a scanning blur makes the line SLANT instead of just a horizontal blurring. Jack Jack, Thanks for sending that to John. Since John ran a vector analysis on those previous frames, I guess we could treat the CURB as a vector. Watch the shadow angle of Altgen's feet, change on the curb. With the camera movement involved between these two frames, why doesn't the CURB move in accordance? As John stated, I too believe the background and foreground are on different layers. chris Just curious Chris, exactly how do you think the curb SHOULD look based on the amount and direction of the blur? what better spot for a matte line, eh? the grass edge where it meets the curb...If the camera was focused on the limo, the curb become one with the foreground (lower portion of the image, hence same level of blur (perhaps slightly more) and blur direction as the limo.... Link to comment Share on other sites More sharing options...
Craig Lamson Posted July 14, 2007 Share Posted July 14, 2007 I sent Chris's study to John Costella for his opinion. He did a quick vector analysis of this and adjacent frames, and assures me that the leaning curb mark appears in other frames and is consistent with panning blur of the background. These factors make understanding Z blurs difficult: ...panning movement of camera (blurs background) ...movement car (blurs car and occupants) ...vertical jiggle of camera (makes erratic blurs) ...combinations of the above (makes complex blurs) Costella made a year-long study of Z-blurs and found that the blurs were manipulated with almost mathematical precision...WITH A FEW EXCEPTIONS which he has previously described. He reiterates his view that the background grass is from a separate film than the foreground, joined at the straight curbline. I must defer to John's superior expertise, though I still do not quite visualize how a scanning blur makes the line SLANT instead of just a horizontal blurring. Jack Jack, Thanks for sending that to John. Since John ran a vector analysis on those previous frames, I guess we could treat the CURB as a vector. Watch the shadow angle of Altgen's feet, change on the curb. With the camera movement involved between these two frames, why doesn't the CURB move in accordance? As John stated, I too believe the background and foreground are on different layers. chris Just curious Chris, exactly how do you think the curb SHOULD look based on the amount and direction of the blur? what better spot for a matte line, eh? the grass edge where it meets the curb...If the camera was focused on the limo, the curb become one with the foreground (lower portion of the image, hence same level of blur (perhaps slightly more) and blur direction as the limo.... Looks like a crappy spot for a matte line to me. The blur changes with almost every frame making it pretty tough to create the proper blur to match. Wishful thinking davie.... Link to comment Share on other sites More sharing options...
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