Ocean Colors @ 32mm

Craig Smith wrote:

Is there any noticeable color cast with the Hoya Fusion CPL?

Unless your cleaning these up in post, they look exceptionally good OOC.

I haven't noticed a change to the color cast by the Hoya Fusion CPL ( https://hoyafilter.com/product/fusion_cir_pl/ ) when shooting in the city using Auto WB... until I saw your comment and decided to review the pictures I took this week.  Since buying the Fusion filter with the EF-M 32mm f/1.4 lens I've had no issues shooting with Auto WB but this week I chose to set my WB to Daylight for a change.
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For the shots taken in the morning, I looked at the LCD on the camera and noticed an objectionable "slight-greenish" color when shooting with Daylight WB at the beach and so I immediately changed it to 'Auto WB'... which resolved the issue for me on the spot.  This change altered the amount of green showing up on the beach sand and shifted the hue of the sand in the scene towards magenta.  But of course, by using Auto WB the colors will shift as the camera calibrates the color differently for each shot.  A good example can be seen below where I reset the WB to AUTO...
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UNEDITED* (other than a Curves adjustment to raise brightness).  No change to the WB.
Taken seconds apart.  Color shifts from Cyan (Left) to Magenta (Right)

Note the changes to Exposure and Aperture.  WB remains on Auto.

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I think that using Auto WB was the answer because that's usually where my camera settings sit.  I'm just having fun with the camera/lens here but if I was taking an image for a magazine I'd have locked down the WB with a grey-scale card via a Manual WB setting.  The results from the City the other day were good using this WB setting. Whilst colors can usually be corrected, it's much better to get the best results immediately from the camera so there's little need to tweak the colors. With ocean shots, regardless of camera, filter or lens - I find myself adjusting color vibrancy more now than with Canon compact cameras that I've used in the past.  I used to see much more change from cheaper CPL filters with other cameras. But these days a decent quality CPL filter should be neutral in relation to White Balance. In fact there's a post on the Nikon forum from 2011 with a member stating that they prefer the Neutral ones for beaches.
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I've noticed in the distant past (with other cameras) that I could use a single CPL filter on the same lens and get different shades of blue sky from different times of the day. Shots taken with the sun lower in the sky were always much warmer.   I certainly get a lot better results closer to the equator when visiting tropical destinations.  There seems to be quite a few things that can influence the results.  But I am wondering if I should do a manual WB setting (using a white or grey card) next time I'm using a CPL filter.
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Regards,
Marco Nero.