Jump to content


Photo

Crystal Sync Vs Variable Speed


  • Please log in to reply
2 replies to this topic

#1 Kevin Desson

Kevin Desson
  • Basic Members
  • PipPip
  • 17 posts
  • Other
  • Toronto, Ontario, Canada

Posted 01 November 2005 - 10:15 PM

Can someone please give me a difinitive description of the difference between Crystal Sync and Variable Speed.

i.e. if a camera shoots 24, 29.97fps Crystal and 1-50fps Variable
  • 0

#2 Charles Haine

Charles Haine
  • Basic Members
  • PipPipPip
  • 127 posts
  • Colorist
  • New York

Posted 02 November 2005 - 02:31 AM

"crystal synch" refers to a motor that keeps a perfect 24fps, which is necessary for synching with sound, as otherwise the sound and picture drift from each other. Called "crystal synch" because, much like a crystal controlled watch, it uses the way crystals react to electricity to time out the 24fps (maybe only the older ones did this and the name stuck, I bet newer camera's are computer controlled).

Now, on lower-end cameras (Arri S, IIC, Bolex), you usually have to choose, do you want a crystal motor or a variable motor? Crystal motor can be used for synch, but no slo-mo. Sometimes, you get stuck with a governor motor, which can't do slo-mo, and doesn't keep synch. However, on a modern movie camera, a range of 1-50fps is pretty normal, and when you shoot at 24fps, it is crystal 24, and synchable with sound in post.

That's the short run-down.

chuck haine
  • 0

#3 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19759 posts
  • Cinematographer
  • Los Angeles

Posted 02 November 2005 - 03:05 AM

You can have a camera that runs crystal sync at speeds other than 24/35, while other cameras run "wild" or just fairly constant at other speeds but crystal at 24/25, and some don't run crystal at any speed.

Crystal sync just means that the speed is extremely precise and constant, not an approximation.

For example, if a camera ran at 30 or 60 fps crystal-sync, you wouldn't have flicker problems shooting under standard 60hz gas discharge lamps / ordinary fluorescents, but if it's just a variable speed motor running at 60 fps, you'd probably get flicker from those 60 hz lamps.
  • 0


Ritter Battery

Abel Cine

FJS International, LLC

CineTape

The Slider

CineLab

Media Blackout - Custom Cables and AKS

Visual Products

Broadcast Solutions Inc

Opal

Rig Wheels Passport

Glidecam

Gamma Ray Digital Inc

rebotnix Technologies

Paralinx LLC

Willys Widgets

Metropolis Post

Tai Audio

Wooden Camera

Aerial Filmworks

Technodolly

Broadcast Solutions Inc

Visual Products

Abel Cine

Wooden Camera

Gamma Ray Digital Inc

rebotnix Technologies

Tai Audio

The Slider

Media Blackout - Custom Cables and AKS

Technodolly

Paralinx LLC

CineTape

Willys Widgets

Aerial Filmworks

Metropolis Post

Rig Wheels Passport

CineLab

Ritter Battery

Glidecam

Opal

FJS International, LLC