i have the osmo+.  It is not the X5 camera.
I never go above iso 400 but even at iso 400 the noise is incredible dog crap.
see for example the following video (please forgive the colour, lighting and exposure etc as it was for testing purposes only)
settings were shutter 50, 25fps 4k iso 400
extremely noisy.


ideas why so noisy and if this is acceptable?

What are you talking about? it doesn't look too bad. the osmo+ has a really small sensor so thats how it looks @ ISO 400. Did you do it in D-Log?

I agree, the video looks great, could you please upload original video to Dropbox or Google Driver so that we can download for further analysis? Thanks.

Like Osmo Lover said, the sensor on the Osmo or Osmo+ is way too small to get something decent. Anyway, I agree the noise is visible WAY too visible, but that's, unfortunately, the reality of these products.

You have two solutions here if you want to keep on Shooting with this product.

1. Invest in a good denoiser: Neat video is just INSANELY GOOD. https://www.neatvideo.com/. I am using it on every footage that needs noise reduction and by default, I am using this app as well on all my MavicPro footage to fix the Noise flickering (even in daylight). Great, but be warm, this will take a lot of time to edit and export, be ready.

2. If you do not want to buy Neat and/or be ready to wait in front your PC/Mac to get your video rendered and exported with Neat. The quick and dirty way is to shoot in 4K and export in HD. Your noise will be then 4 times smaller and less visible.

Good luck.