flickering in sharply focused, high-detail scenes

[Joho]

If you're getting recording failures only in scenes with dense, high-contrast edge details, you may want to try using a mild diffusion filter in front of the lens. I suspect these high-bitrate lockups are provoked not by the actual details in the image, but by sharp-edged aliasing artifacts generated by the sensor. Aliasing can artificially enhance the apparent sharpness of an image and it's often difficult to distinguish from genuine image details.

Make a test video of a slow pan across a sharply-focused, high-detail background and examine it at precisely 100% magnification. Any flickering you may see in the scrolling background details is likely due to aliasing artifacts. The aliasing creates spurious details that move slightly in the opposite direction to the panning motion between frames. If you pause the video on any single frame, it will look fine - the flicker is caused by minute discrepancies between frames.

With a diffusion filter, you can mute most of the extreme details that generate aliases before they reach the image sensor. You can't do this filtering in post-processing the video without blunting the genuine details as well. I've gotten good results with a Tiffen Black Diffusion FX3 filter in daylight, and a Tiffen Soft FX3 filter in incandescent light, though I suspect an FX2 or even FX1 may be nearly as effective. In general, I've found that any motion in a video looks smoother and more natural when shot with a deliberate reduction in sharpness.

Hi lpowell,

I hope it is ok that I copied this posting of yours from another thread. I don't want to highjack the other thread and this posting of yours might be extremely helpful also for other forum members.

I experienced exactly what you are describing here. I am using your peak performance patch with a GH13 that I got only four weeks ago. The hack with your patch is absolutely amazing. I have noted, however, an enormous flickering in high contrast - high detail scenes (branches of trees against the sky, old brick walls, etc.) whenever I move the camera very slightly. I am not talking about fast pans - they actually look ok again - because of the motion blur. I mean very slow pans. It is basically unbearable in 1080 50i and 60i - somewhat reduced in 720 50p and largely absent in 720 60p. I was already thinking that I have a faulty body and considered to send it in for repair - but then I would probably loose the possibility to hack, if they update the firmware during service.

Your posting opened my eyes and I will certainly order a diffusion filter. But you also mentioned that the flickering can be reduced in post. I tried different settings in After Effects, Premiere Pro and Sony Vegas - in particular adding motion blur or soften the image and although this reduced the flickering I was unable to get rid of that. So any advice and suggestions how to get rid of the flickering in post would be very much appreciated.