Earlier today I was trying out my g85 and I noticed that the HDMI image looks quite noisy unless you start recording. Here is a video from a few years ago where someone else noticed this as well - The signal looks noisy, but it cleans up as soon as you press record. Now I'm worried because I'm buying cameras specifically for external recording over HDMI... Lots of times when this camera and the g7 are recommended (including by this site) it's partly because of the 4:2:2 over HDMI, but if it turns out the HDMI is noisy like this, then it's not really delivering on that selling point.
Or is this normal? I've never used a gh4 or gh5, maybe HDMI always looks noisy?
Anyway, I'm bummed ever since noticing this, and I figured I'd make a post about it here since in general it seems like if there's anyone who understands this stuff, they would be here.
Potential workarounds -
- Record internally whenever recording externally. Drawback to this is an annoying workflow, exponentially so if you're running a multi-cam setup. And you would need big SD cards if you're doing a long shoot.
- Rig some sort of dummy SD card that tricks the camera into thinking it's recording.
- Set up an SD card to automatically delete files when it's full so you never need to stop recording.
- Find some menu setting or firmware adjustment to force the camera to act like it's recording.
On the other hand, could this actually be a good thing?
It's possible that what might actually be happening, is that once you press record, you stop getting a live view and it's instead playing back what is being written to the card (lagging a frame or two behind.) If that's how it works, then the image would only be less noisy because it's already gone through the h.264 codec and had a lot of the image data thrown out. In that case, it would actually be better to start off with an uncompressed noisy image.
If anyone has any advice or anything, let me know. Currently I'm trying to stomach having to spend another $300/400 per camera (I'm buying eight cameras) for gh4 (which doesn't have in-body stabilization or as good of autofocus) all to get rid of some noise on the HDMI signal.