DVL-Digest 569 - Postings: Index Canon Frame Movie Mode verses Canon Frame Movie Mode verses - "Perry" I don't know any specifics about Canon cameras, but there is a general misconception about Progressive Scan. Nearly all current CCD cameras use progressive scan sensors; ALL the CCD pixels get scanned for every field. What is different between cameras is what you then do with the signal. Usually cameras add adjacent pairs of lines to form each output field, naturally moving the pairs by one line between odd and even fields. This improves sensitivity, reduces noise, and reduces excessive vertical resolution which would produce 'twitter'. This is caused by information that is only on one field and not the other, and therefore flickers at 30(25) Hz. If you wanted a 'raw' progressive scan then it wouldn't look too good! Several Sony cameras have a 'Progressive Scan' mode for print purposes, limited to slow shutter speeds. I assume they add equivalent lines in successive fields in order to restore the sensitivity and noise. The easiest way to achieve a 'film mode' where there is no interlaced movement on the tape, is to throw away every other line and interpolate the missing information from the remaining field. This is what many consumer cameras actually do. The Canon situation is more complicated because they offset the Green against the Red/Blue chips to gain extra resolution. Perry Mitchell Video Facilities http://www.perrybits.co.uk/ (diese posts stammen von der DV-L Mailingliste - THX to Adam Wilt and Perry Mitchell :-) [up] |
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