Canon 10-22mm and CPL filter

[hashcake]

I'm planning on using my 10-22mm in combination with a Hoya Pro1 77mm CPL on our holiday.
However, another member (tdodd) has raised an interesting point and also has posted a photo he took where it showed that one side of the sky is slightly darker than the other when using a super wide angle lens and a CPL.
This will be my first major outing with my 10-22mm and I was wondering if there is any way of avoiding this issue?
There will be plenty of opportunities for photos of mountains across water and lovely skies so the last thing I want to do is avoid using the CPL so I don't end up losing the reflects and get blown skies.
Would it be a case of being careful of the maximum focal length I use or is there anything else I can do to avoid the issue?

 

[Mangelwurzel]

I found the same thing out when i did a little research about the Sigma 10-20mm.
On ultra wides the best advice was to use GND filters instead of a CPL.
I remember reading that you could get away with it at focal lengths above 17mm but have not tried it myself.

 

[coldpenguin]

Don't know what angle the 10mm end equates to, but surely this effect would be reduced (or at least balanced at each end) if you used a linear polariser. This might affect focusing on some items (assuming you are doing landscape I doubt this will be a problem), and will allow you to effectively choose the amount of reflection you get.

Here are two boring shots taken same time, but just changing the position of the linear polariser. I will try and dig out a more landscape version later.
1
2

 

[jerry12953]

There's nothing much you can do about it, really.

The area of max. polarisation might be slightly less noticeable if it was in the middle of the frame, or if the sky was partly cloudy. Otherwise you could reduce the polarisation, or avoid the shortest focal lengths.

At 28mm (on full frame) it will still be noticeable unless you're careful.

I don't think it makes any difference if you use linear or circular.

It might be better to use ND grads in some situations, but you can't really replicate the effect of a polariser.

 

[coldpenguin]

Depending on what you want, you could try taking some pics with, then turn around slightly (polarising effect of the earths atmosphere on the sunlight might be different at different angles) and blend the two photos.
tried to take some linear shots earlier, but light wasn't good enough to really show the difference.