Of course as Michelle has stated (and explained it better than I did) I may have been slightly miss-understood. Agenised a heavily overcast sky it is unlikely that there will be a noticeable difference. The case here in Scotland, probably the UK in general and anywhere with similar climate and weather conditions, there is often situations where there is sky that has breaks in the cloud as well as dark and very light patches (this maybe why there is a difference in opinion) This can be noticeably visible using a polorizer. The effect that I have noticed is that it has a tendency to add contrast to some areas of sky detail. I totally agree that a visible difference is much more noticeable with brightly lit blue sky. Michelle, it was not my intention to undermine your superior knowledge. You know that I have the greatest respect for your photography and depth of knowledge, and apologise if I have offended you.

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