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Old 20th Dec 2011, 11:34 am   #1
brenellic2000
Octode
 
Join Date: Aug 2006
Location: Rye, East Sussex, UK.
Posts: 1,647
Default Cine film synch - 5ips Motek

Standard tape speeds (7-1/2ips, 3-3/4ips) don't directly correspond with cine film speeds (18 frames/sec for silent, 24 fps for sound-track stock).

Clearly, depending on frame size (8mm is 80 frames per foot = 6.6 frames/inch; Super 8 is 72 frames/ft = 6 frames/inch), simple maths (in theory) tells us that at 24fps (sound) the direct tape speed should be 3.6ips for 8mm and 4ips for Super 8; or at 18ips (silent) 2.72ips or 3ips.

Motek used phase shift/change to get a 'slow' 5ips from their 'fast' 7-1/2ips using a standard Collaro motor (some sources say 4-1/2ips) to better help cine users who tended to use 3-3/4ips (the closest to cine speed - unless they had a Cinecorder with proper synchronisation).

So, how helpful was Motek's 5ips (or indeed 3-3/4 ips) to cine film users? Is it possible to get an exact speed by phase change and, if so, why would Motek chose 5ips rather than 4ips...

... or have I been at the Christmas cider a tad too early and missed something?

Barry
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