Differentiate between Camera weave and Telecine weave

[petersant]

Hi All,

I'm about to start a S16mm production shooting on Arri SR2 and done steady tests for each mag (x2). both have come back from the lab. The tests were shot double exposed, offsetting the steady test chart slightly between. 

Both tests have a slight weave where the steady test chart grid is stable in the frame, however, the entire frame and its contents are weaving slightly. 

My question is how do you differentiate between camera weave and telecine weave? 

Any help greatly appreciated.

[Dom Jaeger]

When you view a double exposure steady test, the only thing you want to look at is whether the two grids from each exposure are locked together. If there is any camera unsteadiness, the grids will move relative to each other. Don’t pay any attention to whether the entire frame is moving, only look at the two grids and whether there is any movement between them.

If the grids seem locked together, the camera registration is steady and you’re good to go.

[petersant]

Thanks Dom

[Dimitrios Koukas]

It has been a long time since I did this... But you re saying that you have slightly offset the grid in second exposure run? Or it is my bad English maybe.

[David Sekanina]

Instead of a grid, you could shoot a fine dot pattern once, rewind, rotate it slightly a shoot it a second time. the result will be a moire pattern, and the moire will move if the camera is not steady, and can be distinguished better from the scanner's gate weave. I have never tested this though - but will give it a try one of these days.

[Robino Jones]

Ask for an overscan so you can see the film perforations, if the perfs move with the grid then it's the telecine / scanner and if they are super steady then it's your camera.

[Robino Jones]

Here's a hand processed reg test I did with my CP16 with old expired plus-X film.

pass: cp16

 

[petersant]

10 hours ago, Robino Jones said:

Ask for an overscan so you can see the film perforations, if the perfs move with the grid then it's the telecine / scanner and if they are super steady then it's your camera.

Perfect. Makes sense. Thanks Robino

[Robert Houllahan]

I always do an overscan for registration tests and on the Scan Station or Xena which have machine vision optical perf registration so the scan will be rock solid locked to the perfs.

Best practice IMO.

[Carl Looper]

In terms of weave, 16mm film is edge aligned in the camera. Not perf aligned. So any scanners that align 16mm film, using the perfs for registration, will exhibit weave, due to a certain amount of weave in the film stock perfs (relative to the edge of the film). 

Carl