I spent a few days in London, and in my camera bag I always carry a polarising filter, and the value it adds to your images are just fantastic, they are relatively inexpensive and just screw onto the front of your lens.
So, what do they do you may ask? Well, they work just like a set of polarising sunglasses, they remove the glare from the image in front of you, they make the blues go bluer, and so also the greens, and that just makes an image pop. Remember when you look into water with and without those polarising set of glasses, the effect is amazing. This is one effect that you CANNOT duplicate in photoshop, although image blending, or HDR does help.
Below are 3 pics, the 1st one(also at the top) was with a 50mm and polariser, the second with a 24mm without a polariser, and the 3rd image a blend of 3 exposure (HDR). You can see the difference between the 3 images immediately, and the 1st one of course wins hand down. (Not that the others are bad…. )
What is interesting with polarising filters is that they do not work well on wide angle lenses, as the law of physics and the optical design path start to introduce vignette’s and thats just ugly. They also rob you of light, losing sometimes up to 2 stops of light, so be carefull, you may need your tripod.
Hope you have enjoyed this post, and until next time…. good light