Jump to content




Photo

Follow Focus unit gear ratios

follow focus

  • Please log in to reply
1 reply to this topic

#1 Kevin Kelly

Kevin Kelly

    New

  • Basic Members
  • Pip
  • 3 posts
  • Other
  • Dallas

Posted 30 August 2015 - 08:58 AM

Most cinema lenses have about a 300 degree rotation from near focus to far focus.  Typically, follow focus units for these lenses are geared 2:1.  So, does a normal setup like this mean a 150 degree rotation on the follow focus wheel?

 

I've noticed that some follow focus units have a 1:1 gear ratio, to be used with dslr and still lenses.  If you have a lens with a 180 degree focus range, and use a 1:1 gear ratio follow focus, does that mean you get a 180 degree rotation on the follow focus wheel?

 

In general, if the follow focus is matched to the lens you are using, are there any advantages or disadvantages to each combo?

 

Kevin

 

 


  • 0




#2 Mark Dunn

Mark Dunn
  • Basic Members
  • PipPipPipPip
  • 2182 posts
  • Other
  • London

Posted 30 August 2015 - 10:26 AM

The FF unit can't know how many teeth the lens FF ring has.

So the ratio must be between the knob and the gear which drives the lens ring.


  • 0



Zylight

Aerial Filmworks

Willys Widgets

Ritter Battery

CineTape

CineLab

Visual Products

Tai Audio

Broadcast Solutions Inc

Pro 8mm

Metropolis Post

Paralinx LLC

Technodolly

The Slider

Glidecam

rebotnix Technologies

Rig Wheels Passport

Abel Cine

Glidecam

Rig Wheels Passport

rebotnix Technologies

Metropolis Post

Broadcast Solutions Inc

Willys Widgets

Paralinx LLC

Ritter Battery

Abel Cine

Pro 8mm

CineTape

Tai Audio

The Slider

Aerial Filmworks

CineLab

Technodolly

Visual Products

Zylight