Results 1 to 3 of 3
  1. Collapse Details
    Fix for sodium lights in post?
    #1
    Senior Member rzr219's Avatar
    Join Date
    Jan 2012
    Location
    Wisconsin
    Posts
    337
    Default
    Ok, so I shot a last minute Fund Raiser and during 1 number I keep seeing moving in my 7 inch monitor on the left side where a colored light was coming from behind. I looked and also noticed it in my LCD screen. I was unable to do anything because I was already in the middle of it. During intermission I asked what type of lights they had was told sodum lights. Now I am guessing I might have been able to correct before hand with shutter? I was shooting 720P at 30 at 180 degrees. So what is the frequency of sodium lights is it not 60HZ? 2nd question can I fix this in post (it was only 2 numbers not a big deal) as I have no expertness of how to? Next time I would like to just get it right in camera as I didn't know they were using these lights back stage.
    Here is a sample clip, I am open to what I need to do to correct this now and in the future. . . . (the camera shake is me trying to figure out what to do )


    Reply With Quote
     

  2. Collapse Details
    #2
    Senior Member paulears's Avatar
    Join Date
    May 2009
    Location
    Lowestoft - UK
    Posts
    1,646
    Default
    Not sodium - which is a horrible nasty nicotine colour and undimmable. There's actually a similar current live topic on this, but the drapes are lit in LED, and the problem is the fixture on that drape is too close (notice the hotspot), and the cure employed was simply to dim it to try to make the hotspot less obvious - BUT as LED uses PWM to dim - which means for practical purposes that the light is on for half as long as it's off which equates to 50%(ish). So you get a flicker based around the mains frequency. Faster shutter speeds often make the flicker worse. The only real solution is a bit of a fudge. Duplicate the clip, mask off the dodgy area with a soft edge, and slip the timeline a frame. A bit of fudging with the opacity may help - if you are lucky. The trouble is that the mains frequency is often slightly different from the very accurate camera clock, so you can still get the odd bit of flicker. It's time consuming repair work, but can usually be cured to a good degree.

    Sadly, LED products all seem to behave differently to dimming. Some, when dimmed can be seen flickering by your peripheral vision - others dim beautifully. Cheap PAR cans that cost less than thirty pounds rarely have good dimming performance at the lower end, and are often even different within a batch of supposedly identical lights!


    Reply With Quote
     

  3. Collapse Details
    #3
    Senior Member rzr219's Avatar
    Join Date
    Jan 2012
    Location
    Wisconsin
    Posts
    337
    Default
    Thanks for the insight, so if I would have shot at 48 instead of 60 it would be less noticeable? I will try to make some adjustments to my footage and see what it looks like. Next time I guess I should ask what type of lighting and watch a full run through, live and learn.


    Reply With Quote
     

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •