4K Flicker

MikeJorden wrote on 5/25/2015, 12:42 AM
I have a very annoying problem with flickering on dark images from 4k cameras.

I shoot High School Theatre productions. I use 3 HDR-FX100 cameras and one HDR-AX2000. The 3 FX100s are set to 4K. They are fixed in position, one either side of the stage and one at the back of the theatre giving a wide shot. I use the AX2000 to follow the action. I bring all 4 videos into Vegas Pro 12 or 13 and edit using Multi Camera. I edit at 1920x1080 for Blu-ray and then render to MPEG 2 using either the Blu-ray or DVD template in the MPEG 2 Main Concept codec.

The problem I am seeing is that if I have to adjust the brightness of the 4K images to make the videos brighter, I get a lot of flicker from the dark areas of the image. I don't see the same issue with the video from the AX2000 shooting in HD.

The flicker is more pronounced with rendering back to DVD using the Main Concept MPEG 2 DVD Architect NTSC Widescreen template (I use that a lot for DVDs).

The reason I use the AX100s is so I can zoom into the image a pan around during editing. I have to set the cameras to manual exposure to make sure the videos are not over exposed due to spot lights in an otherwise dark stage.

Does anyone have any ideas why the videos are flickering when I increase the brightness and contrast and how I can avoid it?

thanks
Mike.

Comments

balazer wrote on 5/25/2015, 1:38 PM
FX100 is not a 4k camera. Do you mean AX100?

You haven't provided enough info to know what the source of your flicker is. What is the period and the nature of the flicker? If I had to guess, it is compression noise. Make sure you are using a UHS memory card, to enable 100 Mbps recording. But mostly I would say you need to adjust your expectations about the shadow performance from this class of camera. You can't boost the shadows that much and expect them to still look good. Your goal should be to set the exposure in the camera as close as you can to the correct setting.
PeterDuke wrote on 5/26/2015, 1:42 AM
" I get a lot of flicker from the dark areas of the image."

That reminds me when I used to use the Shadow/Highlights effect in Adobe Premiere Elements (may be the same for Premiere Pro and After Effects). To get rid of the flicker I had to set the default min black to zero. Can you clamp the min black to the standard broadcast level?