@HoppyUK Thank you for the suggestion :}
You're welcome Ash. To get you started, here's a quick guide.
Polarising filters can either have little or no effect, or can be quite dramatic. It depends on how much polarised light there is about. Light from a clear blue sky is strongly polarised and when you get the angle right, a polariser can make it go very dark indeed, while clouds remain white. But if it's overcast, you'll get zip.
Light reflected from non-metal surfaces is also polarised so, again if you get the angles right, you can see through water or glass, or reduce or eliminate reflections from foliage, grass, leaves etc. This is why landscapers love them - makes things look richer, and with trees for example, there are always a few leaves that just happen to be at the right angle
For blue skies, the optimum angle is 90 degrees to the sun. Make a 'gun' with your finger and thumb at right angles. Point your finger at the sun, and as you rotate your finger, your thumb will scribe an arc in the sky marking the zone of maximum polarisation.
From this you will understand that polarisers are not much use with a sunset, because the arc of polarisation will be above or behind you. But if the sun is high, directly above, the arc will run 360 degrees around the horizon. Think about it
Most of the time, if the sky is blue, you will get something worthwhile. Try it, and rotate the filter to see the effect in the viewfinder. Some people say you can't use a polariser with a very wide-angle lens but that's rubbish. Of course you can, but if the sun is low (not usually a problem if the sun is high) because wide angles take in a large amount of sky, the polarised zone can appear as a dark patch. If you get that, sometimes it doesn't matter, sometimes the effect is made less visible by clouds, or you can zoom longer to make it less prominent, or rotate the filter to reduce the effect (you can also shift it around a little with rotation) or if all else fails, just take it off.
The angle for reflections is 30-40 degrees to the surface. Polarisers don't work on metal because light is part of the electro-magnetic spectrum, but painted metail is fine, eg cars.
Try this. Find a dark shiny car and stand at 30-40 degs to the side. As you rotate the filter, the reflections will come and go from the doors, and do the same off the roof, windscreen and bonnet, at 90 degrees to eachother. You can't have both at the same time.
If you're shooting water, the rotation of the filter is usually about the same to both darken the sky and kill the surface reflections, which is handy. Same for motorsport - you can get a blue sky and reduce windscreen reflections at the same time, if you're lucky.
Use a polariser with care on people. It can take the shine off skin - sometimes effective, eg shiny bald heads, sometimes makes them look a bit like putty. The trick with polarisers is to know when they're likely to work, then give it a try and rotate for best effect. For landscapes especially, chances are you'll like it
