Author Topic: Black calibration best practices  (Read 566 times)

1022mm

  • Newbie
  • *
  • Posts: 28
    • View Profile
Black calibration best practices
« on: March 20, 2019, 10:16:10 AM »
I've been spending the past few days ironing out the kinks of my camera setup and workflow.  Everything is working great so far, with the exception of the vertical sensor banding.    I haven't been able to get consistent reduction in that using black calibration.     Is there a best practice for this?   I read on the hispeedcams.com blog that they had some success doing two black calibrations approximately 20 minutes apart, one at startup and a second after the camera had warmed up.    That hasn't worked as well for me yet.  I'm making extra sure the lens is completely blacked out when doing my calibrations.   Is there anything else I should be doing?

Has anyone had success generating a mask of the banding to correct in post?  Thanks!

Edit: I'm shooting at 1280x720 at the max framerate (1502) at default exposure settings (0db gain, etc) and saving in RAW.  Attached an example - 2 black calibrations about 5 minutes apart were performed before this was shot.
« Last Edit: March 20, 2019, 10:32:04 AM by 1022mm »

JamesB

  • Jr. Member
  • **
  • Posts: 60
    • View Profile
Re: Black calibration best practices
« Reply #1 on: April 02, 2019, 10:18:59 PM »
Thanks for reading the blog!

I personally do the following now on the Chronos:

1) Start up camera...
2) Do black calibration immediately.
3) Wait up to 15min redo black cal
4) Wait an extra 15min do a new Black cal then ready for first shoot.
5) Repeat black cal every 30min to 1hr of continued operation.

Sure it is laborious but it is really a matter of reducing this artifact as the sensor and camera heat up.  Many slow motion cameras have this problem and some of the best require a new calibration every shot or every time any setting is changed. Edgertronics dobauto calibration on every start up and on every setting change but since it only takes 2sec andchas an automatic shutter curtain it becomes easier. We still saw shadow bands and verticals on edgertronic footage as the camera warmed up or got hotter which is normal in our reviews.

Try NeatVideo noise reduction plug in, it does wonders with any residual banding.