Forums
in > Search
Welcome to Pinnacle Systems - Forums Sign in | Join | Help

Need help best adjusting for backlight

Last post 06-27-2020, 18:53 by jjn. 12 replies.
Sort Posts: Previous Next
  •  06-24-2020, 19:05 801151

    Need help best adjusting for backlight

    Greetings,

    I am working on a wedding video from late last summer. I have experience with editing, but am no where near an expert.  I am struggling with a key moment, bride-father dance.  The problem is the backlight, causing them to darken throughout the clip.  From what I see it is worsened by the father wearing an all dark shirt. 

    I have 23 ultimate.  I have tried the LUTs with Auto Color adjustments, but it doesn't look good because the camera adjusting through the clip.  I found under Effect/Color/Brightness and Contrast, but I don't really know if that's a good choice. 

    I am struggling with this and figured I would post this here.  Any suggestions?  

  •  06-25-2020, 2:32 801153 in reply to 801151

    Re: Need help best adjusting for backlight

    I don't think there is a single "magic Bullet" solution to this - you probably would have found it by now.

    I assume that you have shot this in an auto exposure mode on the camera without setting a backlight adjustment? Basically. unless you were using a top range camera that shot in RAW or DLog, what's lost is nearly all lost - there is little latent image to rescue. Was this a natural/white backlight or disco lighting? If the light was disco lighting and the camera was set to auto colour balance, that's a whole additional set of issues, but I'd concentrate on repairing the exposure first.

    If you had set a backlight compensation of 2 or 3 stops, do you think this picture would be OK or at least useable? If so then begin with the Basic set of controls, switch on the videoscope and increase the Exposure setting by  a few stops. The backlight is now going to burn out, but expose correctly for the foregound. Unless the exposure error was so great that you have crushed all the detail in the dark areas, you should be able to adjust the Blacks, Shadows and Mid-range sliders to improve the details in these ranges. Now adjust the brighter parts to see if you can reduce the amout they burn out.

    An alternative would be to apply an RGB Tone Curve, but the principle is the same.

    With that as a starting point, you can then try adjusting the values dynamically using keyframes - I assume the exposure error varies depending one the framing.



  •  06-25-2020, 6:35 801156 in reply to 801153

    Re: Need help best adjusting for backlight

    If you can post a screen shot of one of the frames, that might help in trying to come up with a solution to this.

    Here is how to add a SCREENSHOT to your post. 

     

  •  06-25-2020, 18:15 801172 in reply to 801156

    Re: Need help best adjusting for backlight

    Attachment: backlight problem.jpg
    Faces blurred.  First screenshot wide shot of scene, original.
  •  06-25-2020, 18:17 801173 in reply to 801172

    Re: Need help best adjusting for backlight

    Faces blurred.  Second screenshot close up, original.
  •  06-25-2020, 18:19 801174 in reply to 801173

    Re: Need help best adjusting for backlight

    Faces blurred.  Last screenshot close up, I applied Effect/Color/Brightness and Contrast set at RGB brightness all 8, RGB contrast 90 (that was after a lot of troubleshooting, it helped but that was my novice attempt to fix it.)
  •  06-25-2020, 18:54 801176 in reply to 801153

    Re: Need help best adjusting for backlight

    JJN, 

    Yes it was shot in auto, no backlight adjustment (I'm use to nice lighting), not in RAW or DLog.  It was filmed with Sony FDR-AX53, I am not sure if it can record in RAW format (by the way what is DLog?)

    I posted some screenshots, it was natural light from a lake in the background.  It was in a tent with a incandescent chandelier for added light.

    I am not sure about the backlight compensation, looking back I sure wish I did. 

    If you don't mind, please explain steps on those adjustments in the Color/Basic set of controls.  I tried to follow, but am not sure about the terms.  I used Color/Basic turned on the scope but don't know what a good adjustment looks like.  I tried some adjustments in there, below is a screenshot of them it does lighten the picture.  

    How do you apply with RGB Tone Curve? I see where to do it but besides moving the curve around do not know the correct way to do it.

    Here is a screenshot with the Color/Basic settings tried to follow what you said. I'm not sure what about "few stops" I moved the mouse wheel twice and got 40, but I don't think that is what you meant.

     

     

     


  •  06-25-2020, 23:26 801178 in reply to 801174

    Re: Need help best adjusting for backlight

    Attachment: Grabbed Frame 2.jpg

    I was just fooling around with PS12 and this is the best I could get.

     


  •  06-26-2020, 3:10 801180 in reply to 801176

    Re: Need help best adjusting for backlight

    Attachment: expose +25.jpg

    Below is a basic starting point - I'm using the Waveform scope as it shows exposure levels (the vector scoip is for colour balance)

    All I've done is increase the exposure - this is what the shot would have looked like if you were using backlight compensation. Notice how the dark areas have become noisy, and there are no real black areas - this is a result of the grading rather that doing it in-camera. The burnt out background would have happened anyway.

    I've drawn a red circle around the bit of the waveform we are interested in - the faces. See how they have been lifted from the bottom quarter of the waveform range more into the middle.


  •  06-26-2020, 3:20 801181 in reply to 801180

    Re: Need help best adjusting for backlight

    Attachment: Tone Curve.jpg

    The next stage is to try to move the faces nearer the centre of the range, restore the true blacks and stop some of the highlights from burning out. Here I have switched to the Tone curve.

    Each time you click on the line, you ad another node, and by draging the nodes you create a shape - the left edge is black, the right edge is white and the vertical scale is the output level for a given input.

    The curve I've draw flattens the blacks, streches the mid tones and suppresses the highlights.

    Notice what is showing on the waveform.

    I'm sure you can improve on that, but notice that the same settings applied to the wideshot probably won't be appropriate, so you will need you keyframe the effect as the shot zooms in.


  •  06-26-2020, 3:55 801182 in reply to 801181

    Re: Need help best adjusting for backlight

     BTW, I should have typed Dlog-M - it's a shooting preset used by DJI drones and other devices, one of a number of shooting that attempt to preserve the dynamic range of a shot, but you have to grade them afterwards to make the pictures look good.
  •  06-27-2020, 16:47 801222 in reply to 801182

    Re: Need help best adjusting for backlight

    Thank you for the tips, it's about 5 minutes of footage. I'm working on keyframes with the Basic adjustments.  Start with Exposure then adjust BLK, Shadows, MidRange (these I found to adjust opposite the Exp), Vibrance(follows Exp). That waveform scope is quite useful. Because of the keyframes, I'm not comfortable with the ToneCurve adjustment. 

    I really appreciate the input provided.  I will definitely keep in mind the camera settings when I'm in this predicament again. 

    Take care. 

  •  06-27-2020, 18:53 801228 in reply to 801222

    Re: Need help best adjusting for backlight

    Glad you are making progress. Good luck :-)
View as RSS news feed in XML
Copyright © 2012 Corel, Inc.. Terms of Use | Privacy Policy