Good Evening,
I thank you ahead of time for your patience, pictures will follow later for this post. This weekend has been busy, I still have to go through pictures from my 5 year old's birthday party.
Today I am going to talk about equipment starting with filters. Let me start off with saying we want good filters. Anything we put in front of the lens alters the quality of the light hitting the sensor. Poorly made filters will potentially degrade the image quality and/or have color casts. Most filter effects can be done in the camera or in post processing. The ones that can't without difficulty are CPL and Neutral Density aka ND, normal ones and graduated ones too.
We are going to talk about CPL filters which have some useful effects today. They can increase the contrast of the scene which can be very useful in landscapes and images with some clouds in the sky or both, limit reflections on water and non metallic surfaces, reduce glare, make flat screen images disappear, and make plants look more vibrant. I have also read that they make rainbows more prominent in photos, I have never had a chance to test it.
Here is the difference it makes in the sky with clouds, darker greens can be noticed on the tree too.
Some out there may be thinking that all of these things are great let's get one and leave it on the lens all the time, there are some drawbacks. A good one is usually expensive, so I recommend getting a good quality one that fits your largest lens then step rings for the smaller lenses. They decrease the amount of light hitting the sensor by a stop or so. The effect isn't as great on an ultra wide lens.
I have used Hoya, BW, and Tiffen with good effect. Get one if you are so inclined and go out and shoot.
~Scott