Biggin Hill 2009

[StevenWilliams]

Originally Posted by Simon

Talking of polarizing filters, there are several types but the one you'll be wanting is circular polarizer. Circular is because not only does it polarize the incoming light into the lens but after it's passed thru the first polarizer another filter 'twists' (if that's the right term?) some of the light through 90 degrees. This is so the autofocus of your camera has something to focus onto as polarized light sometimes stops the AF working properly (or so I am led to believe).

The circular polarizers work by having a fixed element and a rotating element. The rotating element you turn by hand whilst looking through the view finder. You can see the changes in your finder as you turn it. Getting the right amount of polarization takes a little practice as sometimes you can make the sky look too blue at the expense of perhaps washing out something you'd rather not. They can be a bit of a pain for 'quick' shots such as the aircraft as you often wont have time to set up the 'perfect' polarization for the shot. Best you can do is stand so the sun is in a fixed place (either behind or to your left/right) and point the lens at a mid-way point in the sky then adjust for that. You'll then have a fairly good success rate for the shots you then take. If you move or the sun moves significantly (if you're there all day, for example) then adjust the polarizer accordingly.

You'll also loose a couple of stops of light with the polarizer so expect that when the light levels start fading you'll either have to have longer exposures (steady hands!) or remove the polarizer to maintain a good light level.

Hope that gives you something to at least ponder

Incidentally, B+W (a German company) do one of the best circular polarizers on the marked in my opinion (which is the one I use). They ought to fit all modern SLR-type lenses so there's bound to be one that'll fit yours.

Thanks

I already have a CPL filter. I bought it for zoo visits where you have to take photos through glass. it removed the reflections. I never thought of using it for sky shots.