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
  • 20073 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


Gamma Ray Digital Inc

Media Blackout - Custom Cables and AKS

The Slider

New Pro Video - New and Used Equipment

Wooden Camera

Abel Cine

Broadcast Solutions Inc

Technodolly

Glidecam

Ritter Battery

Metropolis Post

FJS International, LLC

Aerial Filmworks

Tai Audio

Rig Wheels Passport

CineLab

rebotnix Technologies

Willys Widgets

Paralinx LLC

CineTape

Visual Products

Rig Wheels Passport

Willys Widgets

Visual Products

Broadcast Solutions Inc

CineLab

Glidecam

Media Blackout - Custom Cables and AKS

Gamma Ray Digital Inc

rebotnix Technologies

Metropolis Post

Ritter Battery

Aerial Filmworks

Abel Cine

The Slider

New Pro Video - New and Used Equipment

CineTape

Paralinx LLC

Technodolly

Wooden Camera

FJS International, LLC

Tai Audio