I'm mainly filming videos on this trip, and I've noticed that Sony's custom white balance keeps changing. Does anyone know why?（I've already customized the white balance using my white fins.）

A6700+1650ii+WWLC，ISO Auto。

I uploaded a video, and there's a very noticeable change in color between the 6th and 8th seconds.

Maybe the auto iso shifting which can affect color balance as the camera angle changed and let more warm sunlight in the shot.

I am finding fixed iso, shutter, aperture and white balance, to work best. Only thing in auto is focus.

Edited October 10Oct 10 by Ronscuba

I had to take screenshots to see it, but I think I see it now. You're referring to the magenta spike in the water column, right?

I'm on the A7SIII and did quite a lot of manual (custom) white balance tests recently. The camera sets a Kelvin value and usually a magenta adjustment, say M2 or M4.

But this is strongly related to light intensity. A change in angle or clouds overhead will affect this, as will changes in exposure.

Like Ron wrote, auto-ISO is the strongest culprit here, since you're not changing angles.

My theory is that as the manta hides some sunlight, auto-ISO adjusts exposure, but this affects the overall light, and your custom WB's magenta correction gives you a magenta spike in the water column. It could also be compounded a slight change in angle as you tilt upwards.

Manually setting ISO could probably help.

Edited October 11Oct 11 by bghazzal

4 hours ago, bghazzal said:

Have you encountered a similar issue with the A7SIII in natural light? Next time, I'll try using a fixed ISO to see if that resolves the problem. I'd also like to know if this issue is specific to certain Sony models.

I've noticed that this issue occurs almost exclusively in videos with a blue water background.

1 minute ago, boduoguo said:

Have you encountered a similar issue with the A7SIII in natural light? Next time, I'll try using a fixed ISO to see if that resolves the problem. I'd also like to know if this issue is specific to certain Sony models.

I've noticed that this issue occurs almost exclusively in videos with a blue water background.

Not really, but I haven't shot a lot of wide angle ambient light with it. The A7SIII initially had a very specific MWB colour shift issue ( see https://www.youtube.com/watch?v=NMsrDxw0FZ8 ), but this was resolved through firmware updates
what I did find was that setting MWB gave quite different results at depth, even if environmental changes were small.

What picture profile are you shooting in? I started in HLG3 but this caused custom white balance issues - I'm in picture profile off now, since I don't want to deal with S-log3 and ETTR for what I do, which is mostly artificial light dominant or mixed lighting macro

43 minutes ago, bghazzal said:

I'm using PP off

Maybe it has something to do with ISO; I'll try setting a fixed ISO next time.