Jump to content


Photo

Sensor to Flange distance of URSA Mini PL


  • Please log in to reply
3 replies to this topic

#1 Tom Visser

Tom Visser
  • Basic Members
  • PipPip
  • 18 posts
  • Sound Department
  • Hawaii

Posted 08 February 2018 - 03:41 AM

Can anyone tell me what the flange distance is for the URSA Mini PL (not the Mini PRO - unless they happen to have the same distance - highly probably I guess)?  Specifically, the distance from the sensor to the face when you remove the PL mount.  Why?  I'm trying to fabricate a custom adapter that happens to use the B4 adapter, but I suspect that with the optics in there, its not simply the standard 48mm of the typical B4 flange distance.

 

blackmagic_design_cinecamursamtb4_b4_lens_mount_for_1496078415000_1186264.jpg


  • 0

#2 Phil Rhodes

Phil Rhodes
  • Sustaining Members
  • 12134 posts
  • Other

Posted 08 February 2018 - 05:08 AM

For that you'd need to get hold of a camera and measure it. There isn't, as far as I know, any standard involved in a bit of custom design like that.


  • 0

#3 Dom Jaeger

Dom Jaeger
  • Basic Members
  • PipPipPipPip
  • 1691 posts
  • Other
  • Melbourne, Australia

Posted 08 February 2018 - 05:54 AM

You'd want to measure the PL mount from flange to seat and subtract that figure from 52.00mm to get the optical depth from seat to sensor. It's very hard to measure to the actual sensor since it will have a protective cover glass. (But no OLPF with Ursa Mini I think?)

Given that flange depth tolerances are around 0.01mm, the final shimming is best done with a test lens that is accurately collimated.
  • 0

#4 Tom Visser

Tom Visser
  • Basic Members
  • PipPip
  • 18 posts
  • Sound Department
  • Hawaii

Posted 08 February 2018 - 06:14 AM

You'd want to measure the PL mount from flange to seat and subtract that figure from 52.00mm to get the optical depth from seat to sensor. It's very hard to measure to the actual sensor since it will have a protective cover glass. (But no OLPF with Ursa Mini I think?)

Given that flange depth tolerances are around 0.01mm, the final shimming is best done with a test lens that is accurately collimated.

 

That's more or less the plan, get close as possible (hopefully undercutting a bit) with the first machined part - assemble the front and rear mounts, then shim until it tests spot on with the lens, then machine the final part maybe 0.5mm undercut so I can have 1 shim in place in case I need room to adjust either way in the future.


  • 0


Wooden Camera

Media Blackout - Custom Cables and AKS

Aerial Filmworks

FJS International, LLC

CineTape

Willys Widgets

Glidecam

Ritter Battery

The Slider

Rig Wheels Passport

Tai Audio

Broadcast Solutions Inc

CineLab

rebotnix Technologies

Technodolly

Paralinx LLC

Abel Cine

Visual Products

Metropolis Post

Gamma Ray Digital Inc

Rig Wheels Passport

Willys Widgets

Broadcast Solutions Inc

Tai Audio

Paralinx LLC

CineTape

Aerial Filmworks

The Slider

Glidecam

Gamma Ray Digital Inc

Visual Products

Wooden Camera

Technodolly

FJS International, LLC

CineLab

Metropolis Post

Abel Cine

rebotnix Technologies

Media Blackout - Custom Cables and AKS

Ritter Battery