by Jeffrey Klug
I have gone to a new system of filters, it is the Lee filter system. I use these filters for increasing my exposure to get the long exposures of 5 seconds to 1 minute or more. They are glass square filters that fit into a filter holder. This is great because you only need to buy one set of filters and then get the different adapter rings to fit each of your lens. The filters I use are a polarizing filter (105mm round filter) and two different neutral density filters, one is a 6 stop filter, that they call the Little Stopper, and one that is a 10 stop filter, called the Big Stopper.
I like using these filters because they cut the light from 6 to 10 stops. When doing this it is hard to see through the viewfinder, with the square filters, you can slide them out of the way very easily, instead of the round screw-in filters which you have to unscrew which takes a lot more time to due. After doing that a couple of times in an hour, you tire of it pretty quickly. With the slide in filters, you just slide them out of the way, then when you are ready slide them back in place.
The filters work great for making water flow and turning it silky looking, or smoothing out the waves from the ocean, any place where using a long exposure will make the image look different and sometime more like what we see, the water is not frozen in time, it is moving. The filters allow you to get those long exposure times.
The polarizing filter is good for seeing into reflections and intensifying the color in the scene. You can see into the water, or deepen the blue sky or the green grass. Having one filter that is 105mm in size lets you use just this one filter with all of your lens, from the 16mm wide angle to the 200mm telephoto.
The lens are made of glass, so you do have to be careful with them. They are also very expensive. The filters are The Big Stopper $140, The Little Stopper $150, the Polarizing filter is $270 plus $65 for an adapter ring to hold it to the holder, and the holder is $90 and $65 for each adapter ring. If you compare this to buying individual filters, you will have a saving depending on the quality of the filter.
You can find more information on Lee Filters at www.leefilters.com. You can purchase them at Adorama (http://www.adorama.com) or B & H Photo (http://www.bhphotovideo.com), or I usually get them at Unique Photo (https://www.uniquephoto.com). They all have them for the same price.
You can purchase the Lee filters through the below links.