QuestionFirst polariser for autumn walks - which one, and why does my sky go patchy?

Morning all. I've got an RP with the 24-105 STM and I'm planning lots of autumn walks round the Mendips and the Cotswolds this year. Borrowed a friend's cheap polariser last weekend and loved what it did to the leaves and the water, but at the wide end the sky went a bit blotchy, darker on one side than the other. Was that the filter being rubbish or something I did? And if I buy my own, is it worth spending proper money? It's a 67mm thread. I don't want a whole filter system, just one thing that lives on the lens.

G

That's not the filter, that's physics. A polariser darkens the sky most at 90 degrees from the sun, so at 24mm you've got enough sky in the frame that one side is at maximum effect and the other isn't. Zoom in a touch or turn the ring back so it's less strong. A decent slim one from Hoya or B+W is plenty, no need for a system... and I say that as somebody with far too many filters. Cheers

darkslide said:

A polariser darkens the sky most at 90 degrees from the sun

Oh that makes so much sense! So it was me, not the filter. Glad I found out before I blamed it in front of my friend.

G

I have used the same B+W circular polariser on my 24-70 for the better part of fifteen years, and it has outlasted two cameras. Buy a good one once. Cheap ones are often slightly coloured, which you will notice as a faint blue or warm cast in every photograph you take with it, and they tend to be thick enough to darken the corners at the wide end.

May I add one point that is rarely made. In autumn the polariser earns its keep not on the sky but on the foliage. Wet leaves reflect the white sky, and that glare is what makes autumn colour look washed out in photographs. Turn the filter while looking at a wet beech or a maple and you will see the colour come back quite dramatically. The same applies to water in streams, of course, though do leave a little reflection in or it can look rather dead.

The Mendips should be lovely in a month or so. I hope you have better luck with the weather than we usually do in Harrogate.

Kind regards

Echo all of the above, and remember to take it off when the light goes! Lost a whole blue hour once because I'd forgotten it was still on and couldn't work out why everything was so dark...

Also small thing, a polariser costs around 1.5 stops of light, so in the forest your shutter speed will drop. With the IS in that lens it's fine, but check it. And in the mountains, at altitude the sky is already very dark blue, so with polariser it can look almost black. I turn it less up there.

Bought a slim Hoya in the end and took it up Crook Peak yesterday. Turned it down at the wide end like you said and the sky looked normal, and the wet bracken was every colour going. Took Harrogate's advice on the leaves too, it really does make the colour come back. Thanks everyone!

G